Population estimates and monitoring of Laysan Teal

Transcription

Technical Report HCSU-021
POPULATION ESTIMATES AND MONITORING
GUIDELINES FOR ENDANGERED LAYSAN TEAL,
ANAS LAYSANENSIS, AT MIDWAY ATOLL:
PILOT STUDY RESULTS 2008–2010
Michelle H. Reynolds¹, Kevin W. Brinck², and Leona Laniawe¹
¹U.S. Geological Survey, Pacific Island Ecosystems Research Center,
Kilauea Field Station, Hawaii National Park, HI 96718
²Hawai‘i Cooperative Studies Unit, University of Hawai‘i at Hilo,
Pacific Aquaculture and Coastal Resources Center, P.O. Box 44, Hawai‘i National Park, HI 96718
Hawai‘i Cooperative Studies Unit
University of Hawai‘i at Hilo
Pacific Aquaculture and Coastal Resources Center (PACRC)
200 W. Kawili St.
Hilo, HI 96720
(808) 933-0706
January 2011
The views and conclusions contained in this document are those of the authors and
should not be interpreted as representing the opinions or policies of the U.S.
Government. Mention of trade names or commercial products does not constitute their
endorsement by the U.S. Government.
Technical Report HCSU-021
POPULATION ESTIMATES AND MONITORING GUIDELINES FOR
ENDANGERED LAYSAN TEAL, ANAS LAYSANENSIS, AT MIDWAY ATOLL:
PILOT STUDY RESULTS 2008–2010
Michelle H. Reynolds¹, Kevin W. Brinck², and Leona Laniawe¹
¹U.S. Geological Survey, Pacific Island Ecosystems Research Center, Kīlauea Field Station,
Hawai'i National Park, HI 96718
² Hawai'i Cooperative Studies Unit, University of Hawai'i at Hilo, Pacific Aquaculture and
Coastal Resources Center, P.O. Box 44, Hawai‗i National Park, HI 96718
KEY WORDS
mark-resight population estimators, Laysan Duck, Midway Atoll, closed populations, LincolnPetersen, detection probability, monitoring protocols
CITATION
Reynolds, M.H., Brinck, K.W., and Laniawe, L. 2011. Population estimates and monitoring
guidelines for endangered Laysan Teal, Anas Laysanensis, at Midway Atoll: Pilot study results
2008-2010. Hawai'i Cooperative Studies Unit Technical Report HCSU-021. University of
Hawai'i at Hilo. 67 pp., incl. 4 figures, 5 tables, & 3 appendices.
Hawaiì Cooperative Studies Unit
University of Hawaiì at Hilo
Pacific Aquaculture and Coastal Resources Center (PACRC)
200 W. Kawili St.
Hilo, Hawaiì 96720
808-933-0706
January 2011
This product was prepared under Cooperative Agreement CA03WRAG0036
for the Pacific Island Ecosystems Research Center of the U.S. Geological Survey
ii
Reynolds, Brinck, and Laniawe
Population monitoring of Laysan Teal at Midway Atoll
2
EXECUTIVE SUMMARY .........................................................................................................................................4
ACKNOWLEDGEMENTS ........................................................................................................................................5
INTRODUCTION .......................................................................................................................................................6
METHODS ...................................................................................................................................................................7
STUDY SITE ............................................................................................................................................................... 7
FIELD METHODS ........................................................................................................................................................7
Population monitoring .........................................................................................................................................7
Capture and marking ...........................................................................................................................................9
STATISTICAL ANALYSES ............................................................................................................................................9
Lincoln-Petersen style abundance estimates ........................................................................................................9
Simple count index of population ....................................................................................................................... 10
Power to detect a decline ................................................................................................................................... 11
Intrinsic growth rate .......................................................................................................................................... 11
RESULTS ................................................................................................................................................................... 11
Lincoln-Petersen style abundance estimates ...................................................................................................... 11
Summary of resight statistics ............................................................................................................................. 14
Simple count index of population ....................................................................................................................... 16
Power to detect a decline ................................................................................................................................... 17
Intrinsic growth rate and carrying capacity ...................................................................................................... 17
DISCUSSION ............................................................................................................................................................. 17
MANAGEMENT GOALS ............................................................................................................................................. 17
BEST ESTIMATES ...................................................................................................................................................... 18
Power analysis ................................................................................................................................................... 18
Mark-recapture likelihood models ..................................................................................................................... 19
Simple index tracking ......................................................................................................................................... 19
Hybrid methods .................................................................................................................................................. 19
Mark-recapture model data collection ............................................................................................................... 20
Lincoln-Petersen style estimates ........................................................................................................................ 20
Indices ................................................................................................................................................................ 21
MONITORING STANDARDS ....................................................................................................................................... 21
Power ................................................................................................................................................................. 21
Continuous resights............................................................................................................................................ 21
All-wetland counts and incidental resights ........................................................................................................ 22
SUGGESTIONS FOR MONITORING .............................................................................................................................. 22
REFERENCES .......................................................................................................................................................... 24
3
APPENDIX 1. ASSUMPTIONS OF LINCOLN-PETERSEN MODELS AND THEIR VIOLATIONS IN
SURVEYS OF LAYSAN TEAL ON MIDWAY ATOLL ...................................................................................... 26
APPENDIX 2. ESTIMATING THE NUMBER OF MARKED LAYSAN TEAL AVAILABLE TO BE
COUNTED: MARKS ESTIMATED ALIVE (MEA) ............................................................................................. 28
APPENDIX 3. MIDWAY ATOLL LAYSAN TEAL RESIGHT SURVEY PROTOCOL................................. 30
INCIDENTAL RESIGHTS ............................................................................................................................................ 30
Possible Band Numbers, Letters, and Symbols .................................................................................................. 31
Permanent Bands ............................................................................................................................................... 31
Temporary Bands ............................................................................................................................................... 32
Aluminum Only .................................................................................................................................................. 32
Band Discrepancy .............................................................................................................................................. 32
PROCEDURE FOR STANDARDIZED RESIGHT SURVEY OF ALL WETLANDS ................................................................ 34
Materials Needed: .............................................................................................................................................. 34
Procedure ......................................................................................................................................................... .34
Double Counts.................................................................................................................................................... 37
Temporary Bands ............................................................................................................................................... 38
Resight Survey Data Entry ................................................................................................................................. 38
PROCEDURE FOR PILOT ATOLL-WIDE ALL-WETLANDS COUNT .............................................................................. 43
Atoll-wide All-Wetlands Count Data Entry ........................................................................................................ 44
ATTACHMENT 1. REVISED DATA SHEETS: ............................................................................................................... 47
Resight data sheet .............................................................................................................................................. 48
ATTACHMENT 2. MIDWAY ATOLL LAYSAN TEAL SURVEY START LOCATIONS AND DIRECTION OF TRAVEL TABLES
................................................................................................................................................................................ 52
ATTACHMENT 3. MAPS ILLUSTRATING SAND ISLAND AND EASTERN ISLAND SURVEYS ............................... 53
ATTACHMENT 4. MIDWAY ATOLL LAYSAN TEAL RESIGHT REFERENCE,
MIDWAY_RESIGHT_REFERENCE_20AUG2010.XLS .............................................................................................. 56
4
EXECUTIVE SUMMARY
Accurate estimates of population size are often crucial to determining status and planning
recovery of endangered species. The ability to detect trends in survival and population size over
time enables conservation managers to make effective decisions for species and refuge
management. During 2004–2007, the translocated population of endangered Laysan Teal (Anas
laysanensis; also Laysan Duck) was fitted with radio transmitters providing known (―gold
standard‖) measures of survival and reproduction. However, as the population grew, statistically
rigorous monitoring protocols were needed that were less labor intensive than radio telemetry. A
population die-off and alarmingly high number of carcasses (181) were recorded during a
botulism epizootic in August–October 2008, which further reinforced the need for effective
monitoring protocols since this endangered species is vulnerable to catastrophic population
declines. In fall 2008, we initiated a pilot study using standardized surveys with uniquely
marked birds to monitor abundance and estimate the population growth rate of the reintroduced
Laysan Teal. Since few birds carried marks (leg bands) after the 2008 botulism die-off (only
about 15% of the population), and standardized surveys were not yet implemented, the
magnitude of the die-off on the population size was unknown.
To learn more about this endangered species' status and develop monitoring protocols
useful to refuge managers and recovery planners in the U.S. Fish and Wildlife Service (USFWS),
we marked (banded) 252 new Laysan Teal for this pilot project. With skilled refuge staff and
trained volunteers, we conducted counts of marked, unmarked, and unknown birds during bimonthly surveys from Oct 2008 to Jan 2010. We recorded the identities of marked birds
observed, recovered carcasses, and then used the last date a bird was detected alive and the
median resight frequency to conclude if a bird was likely to be alive on a given survey date.
Using mark-resight data and individual resight frequencies, we produced a series of abundance
estimates from surveys that met accuracy criteria and approached ―closed population‖
assumptions. Since only one year of standardized, atoll-wide surveys were conducted, we
analyzed data selected from multiple surveys using Lincoln-Petersen (LP) estimates instead of
multi-year likelihood estimators. We adjusted surveys to account for unknown birds (e.g.,
swimming birds), temporary band loss, and described the frequency of double counting. Double
counting is an important consideration in the population estimate because we found a maximum
of 13% of marked birds were counted multiple times during a survey.
These survey protocols allowed us to estimate the species' post-fledging population
(combined adults and juveniles), and the methods are comparable to those used on Laysan
Island. The Laysan Teal population increased 91% from 247 (95% CI, 233–260) in 2007 to
439–508 in early 2010. There was no change from 2009 to 2010 indicating that there was no
population growth, however, our 2010 estimate should be considered preliminary since only one
month of 2010 resight data was used. We compared a series of direct counts to their
corresponding population estimates during 2008–2009 to evaluate if counts could serve as an
unbiased ―index‖ of population abundance. There was a moderate correlation between
abundance estimates and total birds counted (r2 = 0.51) during resight surveys but a low
correlation with all-wetland counts (r2 = 0.02). This indicated that using direct all-wetland
counts to predict abundance would result in confidence intervals on the order of ± 200 birds,
which is equal to 50% of the estimate. With such large confidence intervals, it would be unlikely
to detect annual changes in abundance or determine the magnitude of a catastrophic decline.
5
To improve the Laysan Teal population estimates, we recommend changes to the
monitoring protocol. Additional years of data are needed to quantify inter-annual seasonal
detection probabilities, which may allow the use of standardized direct counts as an unbiased
index of population size. Survey protocols should be enhanced through frequent resights, regular
survey intervals, and determining reliable standards to detect catastrophic declines and annual
changes in adult abundance. In late 2009 to early 2010, 68% of the population was marked with
unique color band combinations. This allowed for potentially accurate adult population
estimates and survival estimates without the need to mark new birds in 2010, 2011, and possibly
2012. However, efforts should be made to replace worn or illegible bands so birds can be
identified in future surveys. It would be valuable to develop more sophisticated population size
and survival models using Program MARK, a state-of-the-art software package which uses
likelihood models to analyze mark-recapture data. This would allow for more reliable adult
population and survival estimates to compare with the ―source‖ Laysan Teal population on
Laysan Island. These models will require additional years of resight data (> 1 year) and, in some
cases, an intensive annual effort of marking and recapture. Because data indicate standardized
all-wetland counts are a poor index of abundance, monitoring efforts could be improved by
expanding resight surveys to include all wetlands, discontinuing the all-wetland counts, and reallocating some of the wetland count effort to collect additional opportunistic resights.
Approximately two years of additional bimonthly surveys are needed to validate the direct count
as an appropriate index of population abundance. Additional years of individual resight data will
allow estimates of adult population size, as specified in recovery criteria, and to track species
population dynamics at Midway Atoll.
Key words: mark-resight population estimators, Laysan Duck, Midway Atoll, closed populations,
Lincoln-Petersen, detection probability, monitoring protocols
ACKNOWLEDGEMENTS
We thank E. Dominio, J. Shore, G. Shuman, M. Vekasy, and field biologists for
assistance. Matt Brown (USFWS Midway Atoll NWR Manager), Marilet Zablan (USFWS,
Assistant Field Supervisor for Endangered Species), Gordon Tribble (USGS Pacific Island
Ecosystems Research Center, Director), Holly Freifeld (USFWS, Vertebrate Recovery
Coordinator), John Klavitter (USFWS Midway Atoll NWR Biologist/Assistant Refuge
Manager), and Loyal Mehrhoff (USFWS Pacific Islands Fish and Wildlife Office Field
Supervisor) made this study possible. We thank reviewers R. Camp, J. Hatfield, and A.
McClung for comments and feedback which improved this document. Sarah Nash edited and
formatted this report. This study was funded by U.S. Fish and Wildlife Service‘s Ecological
Service‘s Pacific Islands Ecoregion, Midway Atoll NWR, and U.S. Geological Survey, Pacific
Island Ecosystems Research Center. Any use of trade, product, or firm names in this publication
does not imply endorsement by the U.S. Government.
6
INTRODUCTION
Accurate estimates of population size are often critical to understanding population
dynamics, planning conservation actions, and evaluating responses to management (e.g., Johnson
et al. 2006, King et al. 2006, McCartney et al. 2006). The Laysan Teal (Anas laysanensis) is an
endangered species restricted to approximately 10 km2 on Midway Atoll and Laysan Island, and
is one of the most difficult bird species to monitor effectively in the Papahānaumokuākea Marine
National Monument (Sincock & Kridler 1977). This difficulty is due to the Laysan Teal‘s
tendency to hide in dense vegetation, reluctance to flush, and seasonal changes in observability
(Marshall 1992, Reynolds 2002). Mark-recapture is a useful method for estimating population
abundance for animals such as the Laysan Teal, which are difficult to find, but which can be
individually marked (banded) and resighted in the future.
The U.S. Fish and Wildlife Service (USFWS) Recovery Branch requested marked
population studies in 2008 to determine how best to monitor the species‘ abundance and
population status at Midway Atoll National Wildlife Refuge (hereafter the Refuge). USFWS
Recovery Criteria specified abundance benchmarks and population trends to downlist the species
from endangered to threatened. Monitoring standards required that each population of breeding
adults must be stable or increasing, and monitoring data should demonstrate an average intrinsic
growth rate (λ) not less than 1.0 over a period of ≥ 10 consecutive years to account for
population fluctuations (U.S. Fish and Wildlife Service 2009). Two approaches to calculating λ
are to conduct counts of the population at regular intervals to estimate average annual change or
to quantify demographic parameters such as survival and fecundity. Additionally, the Recovery
Criteria specified that only adult populations be used. Fledglings and juveniles are excluded
because adding these groups tends to overestimate the number and size of breeding populations,
thereby underestimating the risk of extinction (U.S. Fish and Wildlife Service 2009).
Before the marked population studies could begin in 2008, botulism (Clostridium
botulinum) type C caused an unusual mortality event for Laysan Teal at Midway (Work et al.
2010). The magnitude of the population decline and the risk to the species was unknown since
no population estimate was determined prior to the die-off. As a result, the Refuge was
interested in detecting emerging catastrophic declines plus annual increases and decreases in
abundance of Laysan Teal (J. Klavitter and M. Brown, USFWS, pers. comm.). The Refuge was
also interested in detecting population responses to management actions, but did not have
specific monitoring standards or adaptive management goals for population responses (Stankey
et al. 2005).
Standards for detecting changes in population abundance should incorporate the
magnitude of change, a time frame for detecting that change, and a measure of statistical
significance (Skalski et al. 2005). An example monitoring standard is "to be 90% likely to detect
a decline that would halve the population in five years." Detecting a change in population
abundance requires the ability to separate a real change in abundance from the uncertainty
inherent in the estimation technique. Collecting data in ways that minimize the sampling error
maximizes the ability to detect a real change in the population abundance (Zar 1996, Seavy &
Reynolds 2009).
7
The unique behavior of Laysan Teal makes surveying the population on Midway Atoll
challenging. The Laysan Teal exhibits nocturnal and crepuscular activity and secretive nesting.
Simple counts would likely underestimate abundance, because the proportion of the total
population observed during any count is unknown and would vary from survey to survey.
Although mark-resight surveys are more complex than simple counts, they are a more
appropriate technique for monitoring this species. Mark-resight methods allow for estimates of
abundance, survival, population growth rate, and other demographic parameters. Likelihood
population models require three years of mark-resight data, but we were able to use this single
year of data from the pilot study to estimate abundance and assess monitoring protocols for the
population at Midway Atoll. We also summarized USGS translocation post-release population
data (Reynolds et al. 2008) for this report to analyze the six year population trend at Midway
Atoll.
METHODS
STUDY SITE
Midway Atoll (28 12‘N and 177 22‘W) is located 1,930 km from Honolulu, Hawaii,
comprised of three islands (Sand, 452 ha; Eastern, 136 ha; and Spit, 6 ha), and protected as a
National Wildlife Refuge (NWR) within the Papahānaumokuākea Marine National Monument.
There are 14 small diverse wetlands on the Refuge totaling about two hectares. In addition to
supporting the re-introduced population of Laysan Teal, Midway Atoll provides breeding habitat
for approximately three million Pacific seabirds.
FIELD METHODS
Population monitoring
From November 2008–November 2009, monitoring consisted of weekly atoll-wide
counts of Laysan Teal using two survey methodologies. The first survey methodology was used
to estimate population abundances (resight survey), and the second provided an index count
(called all-wetland counts; Fig. 1a, b) to be validated using marked population methods. Skilled
observers searched wetlands using 10x binoculars or a spotting scope (40-60x) to detect or read
coded leg-bands of all Laysan Teal visible between, on, and around the wetlands (Appendix 3).
Surveys were initiated approximately two hours before sunset or at sunrise—times when the
greatest number of Laysan Teal are concentrated at interior wetlands. The starting location and
direction of surveys were randomly varied to reduce spatial-temporal bias. This protocol was
similar to methods used on Laysan Island as described in Marshall (1992) and Reynolds and
Citta (2007).
8
a)
Monument
Sunset
Rolando
b)
Figure 1a, b. Survey routes on Sand (a) and Eastern (b) islands. (Full-page versions of these maps are provided in
the Appendix, Attachment 3.)
9
Prior to this study, the U.S. Geological Survey also assisted the Refuge with post-release
monitoring of translocated birds using radio telemetry, and conducted opportunistic pilot surveys
of Sand Island‘s wetlands in January, February, May, and July–September in 2007. A morning
or evening resight survey was conducted on both Sand and Eastern islands in October and
November in 2007. Simultaneous atoll-wide resight surveys were conducted 1–2 times per
month in January and March 2008. We used these early data and data from this pilot study to
construct a time series of abundance estimates and evaluate the sampling to improve survey
methods. For detailed field methodology refer to the survey protocols (Appendix 3). Survey
protocols were updated based on pilot study results, and may be updated in the future based on
future results.
Capture and marking
Laysan Teal were trapped at wetlands, in a variety of terrestrial habitats, and on roads
around Midway Atoll in November 2008, March–May 2009, and September–October 2009.
Most birds were caught at night using a flexible handheld net and headlamps or at crepuscular
periods using noose carpets. A numbered aluminum band was placed on one leg and a plastic
color band with alpha or numeric codes on the other leg of each bird. Nasal or wing marks,
commonly used in waterfowl marking, were inappropriate for this endangered species due to a
high risk of entanglement. All birds were released near their capture site. Prior to this study, all
individuals were marked through 2006, 56 juveniles were marked with permanent bands in 2007,
and 33 birds (6 juveniles, 27 adults) had temporary bands replaced in 2008–2009. The marked
population ranged from 20 birds in 2004 to 300–345 birds by 2009.
STATISTICAL ANALYSES
Lincoln-Petersen style abundance estimates
We used a Lincoln-Petersen (LP) framework (Seber 1982) in which a known number of
birds are marked and released to mix freely in the population, so that during a later survey the
known number of marked birds and the ratio of marked to unmarked birds can be used to
estimate the total population abundance. The LP estimators tend to overestimate population
sizes, especially if few birds are seen or less than 20% of the population is marked (Robson &
Regier 1964; as of January 2010, 50–60% of the Laysan Teal at Midway were marked). We
chose this method because there was only one year of pilot study data, the estimator was simple
to calculate, and the same method had also been used on Laysan Island, permitting comparisons
of population abundance (Marshall 1992, Reynolds & Citta 2007, USFWS 2009).
The accuracy and precision of LP estimates depends upon six assumptions about the
animal population and the efficiency of data collection (Skalski et al. 2005):
1. The number of marks in the population is known
2. The population is geographically and demographically closed (no births, deaths,
immigration or emigration)
3. All animals have the same probability of being caught or sighted
4. Marking does not affect future detection
5. Animals do not lose their marks
6. All marks are correctly reported
It is important to note that the methods used to estimate the Laysan Teal population from
this pilot survey violate these assumptions in important ways, but we have devised methods to
10
compensate for violations. Appendices 1 and 2 provide details. Where there was important
uncertainty (i.e., assumption #1), we presented a range of estimates that can be refined with
additional resight data.
Chapman‘s (1951) bias-corrected hypergeometric modification to the LP estimator is:
Nˆ t
(M t
1)(nt
mt
1)
1
where N̂ t is the population estimate, Mt is the total marked population, nt is the number of
animals counted, and mt is the number of marked animals counted (i.e., resighted), all at a given
time t. A nearly unbiased variance estimator (Seber 1982) is
( M t 1)(nt 1)( M t mt )(nt M t )
Var( Nˆ t )
.
(mt 1) 2 (mt 2)
To explore the quality of the data, we determined the total count and marked population
needed for a LP point estimate with 10% or 25% accuracy (assuming a population of 200–500
birds, the approximate range of our estimates)
Number marked Mt
using standards by Robson and Regier (1964;
Figure 2). Again, mt is the number of birds
resighted during a survey, and Mt is the number of
birds marked in the population (marked estimated
alive, MEA) at the time of the survey, as
estimated from banding and resight data
(Appendix 2). All calculations were carried out
in a Microsoft Excel workbook (Microsoft Corp.
2003; available upon request).
Simple count index of population
We assessed the validity of using the total
number of birds observed in the resight surveys
and the all-wetland counts as an index of a more
detailed LP-style population estimate (Appendix
2) with a simple regression model. An index is a
population assessment technique that uses a
relative difference in abundance (e.g., from an
incomplete direct count) to describe changes in a
population (Lancia et al. 1996). Ideally, an index
is a constant ratio that can be calibrated with the
population estimate. Indices are different from
abundance estimators due to their inability to be
converted to absolute animal abundance, typically
because the necessary auxiliary data to make the
conversion are not collected (Skalski et al. 2005).
We describe the uncertainty in using a count
index to predict total Laysan Teal abundance in
more detail later in this paper. Because the
individual surveys varied in meeting accuracy and
Figure 2. Numbers of birds that need to be
marked and examined for marks on
subsequent surveys to estimate population
size within 10% (bold numbers) or 25%
(regular font) accuracy. This figure is
modified from Robson and Regier (1964).
The bold line represents combinations of
numbers of birds marked and numbers of
birds examined for marks that produce
population estimates accurate within 10% of
a population of 500 (line used in this study).
For example, if the population size (N) is
thought to be about 500, then you would
need to mark ~400 birds if your surveys
detected only 50–60 total birds. If your
surveys typically detected ~100 birds, 300
would need to be marked for estimates to be
accurate within 10%.
11
precision standards, we used only the higher-quality LP estimates, where accuracy guidelines
(total marks plus birds observed > N̂ ) and precision guidelines (coefficient of variation of N̂ <
0.05) were met.
Using the estimated number of marked birds in the population and the actual number of
marks counted during resight surveys, we estimated the monthly probability of detecting an
individual and derived Horvitz-Thompson estimators based on detection probability (Thompson
1992), both for each month and also for morning vs. evening surveys. We compared those
estimators to LP-style abundance estimators using linear regression to test the strength of the
relationship between the two methods.
Power to detect a decline
There are two major sources of variation in the annual estimate of the Laysan Teal on
Midway: actual fluctuation in bird abundance (process variation) and sampling error resulting
from random noise and inaccuracies in field data collection. In order to detect changes in
abundance over time, we would like to calculate a threshold outside which we are confident that
an observed trajectory represents a real trend in the population, beyond the fluctuations
introduced by sampling error.
Intrinsic growth rate
We used abundance estimates from post-release radio telemetry and LP estimates from
resight surveys for a non-linear regression using program R (R Development Team 2009) to
estimate the intrinsic growth rate (λ) and model the potential carrying capacity on Midway Atoll.
Using a logistic growth model of the form
dN
dt
r 1
N
K
N
where N is the abundance and dN
is the rate of population growth over time (the derivative of
dt
abundance with respect to time), r is the natural logarithm of the growth rate (λ), adjusted for
density dependent growth, and K is the carrying capacity, or maximum population the
environment can support. Carrying capacity is likely confounded by events such as the botulism
epizootics in 2008 and 2009, and thus carrying capacity estimates are considered preliminary.
RESULTS
Lincoln-Petersen style abundance estimates
There were 38 atoll-wide resight surveys between October 2007 and January 2010.
Seventeen of these resight surveys were considered high quality surveys and had enough total
resight observations to produce potentially precise (small uncertainty) and accurate (little or no
bias) estimates (Table 1), including one (23 October 2007) with enough information on known
age birds to produce a separate estimate for the number of juveniles. However, three of these
high-quality surveys (5, 12, and 19 November 2008) were made during the botulism outbreak,
when the mortality rate was high, thus violating the closed population assumption of the
Chapman estimator (i.e., marked birds classified as available to be counted may have been dead)
leading to biased estimates. All surveys in December 2009 did not use the standardized survey
12
protocols, although the observer collected useful resight data for detecting individuals and
calculating median resight intervals (observer on different islands on different days). Estimates
that come closest to meeting LP model assumptions, meet accuracy and precision standards, and
were collected by experienced observers using standardized protocol are highlighted and
considered ―best estimates.‖
Table 1. Mark-resight Lincoln-Petersen estimates of Laysan Teal abundance, meeting the Robson and Regier (1964) standards for accuracy and precision and a
coefficient of variation < 0.05. We also show the results of the 23 October 2007 survey, the only data for 2007, and inferred pre-breeding abundance for
2008. Birds whose banding status could not be determined (e.g., swimming in turbid water) were assumed to be marked or unmarked in the same
proportions as those whose status could be determined. Best estimates—those which come closest to meeting LP model assumptions, while also meeting
accuracy and precision standards, and were collected by experienced observers using standardized protocol (two observers survey Sand and Eastern
simultaneously) —are in bold. The 2010 estimates are considered ―best preliminary estimates.‖ Surveys marked with * were conducted using different
methods, influencing the MEA (estimated marks alive). The 90% quantile vs. median detection intervals increase the time allowed to elapse before an
individual is considered missing (dead) and not available to be surveyed. Additional resights will allow for an improved MEA and LP estimate at the
median detection interval (see Appendix 2).
Survey date
23-Oct-07
5-Nov-08
12-Nov-08
19-Nov-08
19-Nov-08
26-Nov-08
17-Dec-08
24-Dec-08
31-Dec-08
5-Oct-09
6-Nov-09
17-Nov-09
1/2-Dec-09*
15/16-Dec-09*
29/30-Dec-09*
8-Jan-10
11-Jan-10
Resight survey results
Resighted
during
Marked
survey
resighted
139
60.0
453
109.6
350
107.2
357
142.5
332
121.0
285
130.3
370
143.9
334
123.8
369
150.2
211
122.2
319
148.5
274
139.3
353
185.0
276
160.7
278
165.4
207
123.2
210
136.9
2010 estimates are preliminary.
Using the 90th quantile detection interval
Using the median detection interval
Marked
birds
92
135
149
156
156
163
200
197
196
282
276
269
268
310
272
215
175
LP
estimate
212.3
557.3
485.8
390.5
427.4
356.2
513.7
530.4
481.0
486.1
592.0
528.4
360.6
268.4
95% CI
(189-236)
(518-596)
(446-526)
(376-405)
(399-456)
(336-376)
(479-548)
(486-575)
(453-509)
(444-528)
(545-639)
(486-571)
(483-539)
(495-568)
(429-484)
(334-387)
(256-281)
c.v.
estimate
0.06
0.04
0.04
0.02
0.03
0.03
0.03
0.04
0.03
0.04
0.04
0.04
0.03
0.04
0.03
0.04
0.02
Marked
birds
94
138
152
159
159
166
205
205
205
293
294
290
287
345
340
322
309
LP
estimate
217
570
495
398
436
363
526
552
503
505
631
570
540
473
95% CI
(193-241)
(528-611)
(454-537)
(382-414)
(406-465)
(342-384)
(490-563)
(504-600)
(471-535)
(461-549)
(579-682)
(522-617)
(515-579)
(549-635)
(531-610)
(493-587)
(439-508)
c.v. estimate
0.06
0.04
0.04
0.02
0.04
0.03
0.04
0.04
0.03
0.04
0.04
0.04
0.03
0.04
0.04
0.04
0.04
14
Table 1 presents two sets of abundance estimates. The more conservative MEA uses the
median interval between detections when estimating the number of marks available to be
counted. There are also preliminary estimates using the 90th percentile of the distribution, which
were used for recent survey dates (late 2009 and early 2010), where there has been little time
after banding birds and less post-survey effort to establish which birds were alive on the survey
date. Early (preliminary) estimates can be enhanced with future resights which improve
estimates of MEA. In addition, on the 23 October 2007 survey all birds were of known age,
therefore we were able to produce separate estimates of adults and juveniles: exactly 92 adults
and 155 (95% confidence interval of 141 to 168) juveniles.
Table 2 presents abundance
Table 2. Total abundance (all post-fledging) and pre-breeding
estimates from the translocation of
estimates for Laysan Teal on Midway Atoll. Before 2008
Laysan Teal to Midway through
all adult birds were given radio transmitters, so the
numbers are considered exact. From 2008–2010 the
January 2010. Total numbers should
abundance estimators are Chapman mark-recapture
be considered "pre-breeding" since a
estimators as described in this document. The 2009 and
combination of juveniles and adults
2010 estimates are of post-fledging individuals in
were used to estimate the 2010 adult
December or January, before juvenile mortality is
population.
This
number
considered to be over, so are over-estimates of the
breeding adult population. Finally, the 2010 estimate is
overestimates the number of potential
based on the number of marks estimated from the 90%
breeders in a year since juvenile
quantile of detection intervals to compensate for the
mortality is higher than adult mortality
absence of post-estimate resight effort to establish which
(Reynolds & Work 2005, Reynolds &
birds were known to be alive at the time of the survey.
Citta 2007, Reynolds et al. 2008,
Total
Work et al. 2010).
Insufficient
adults
resights were made in late 2009, and
and
only two surveys were conducted in
Year
juveniles
95% CI
Adults
2010. Missing and variable survey
2004
20
4
effort also creates a gap in the time
2005
51
24
series for 2008, however, we could
2006
104
51
provide the estimate for 2007, which
2007
247
(233-260)
92
was based upon radio-tracking data of
2008
-(189-236)
212
adults. We lack the resight data in
2009
481
(453-509)
-2008 to make adult (breeding
2010
473
(439-508)
-population) estimates for 2009 using
LP methods.
However, with
additional standardized 2010/2011 resight surveys, pre-breeding adult population size (during
January–March) can be estimated using these methods.
Summary of resight statistics
Resights of Laysan Teal were collected using three basic methods: resight surveys
(standardized resight surveys of both islands), opportunistic resights during all-wetland counts,
and incidental or opportunistic resights. All resights plus re-captures while banding were utilized
to calculate the distribution of detection intervals used to estimate the number of MEA birds in
the population available to be counted as described in Appendix 2.
Table 3 details the distribution of all resight observations where location and method
were recorded. Half of pooled resight observations were from resight surveys, and two-thirds
15
were collected on Sand (vs. Eastern) Island. Incidental sightings were important on Sand Island
and made up nearly one-third of records (Table 3).
Table 3. Distribution of Laysan Teal resights from October 2008 through 11 January 2009, by
island and type of resight effort. The effort proportions differed for each island (Chisquared test
Island.
Island
Sand
Eastern
Total
2
2 =
586.7, p < 0.0001) likely a result of few incidental resights on Eastern
All-Wetland
Counts
402 (7%)
278 (5%)
680 (12%)
Incidental
1870 (32%)
304 (5%)
2174 (38%)
Most resighted individuals (66%) were seen on
both islands, while 51 individuals (12%) were seen
only on Eastern Island (Table 4). Incidental resights
contributed to many detections—17% of birds were
never seen during the standardized resight surveys
(which did not survey all wetlands during the pilot
study). Just two percent of color-banded birds were
missed during surveys and could be recorded only
incidentally (Table 5).
Resight
Survey
1577 (27%)
1330 (23%)
2907 (50%)
Total
3849 (67%)
1912 (33%)
5761 (100%)
Table 4. Location of resights of individual
Laysan Teal from October 2008
through 11 January 2010. Two-thirds
of birds were observed on both
islands.
Sand Only
East Only
Both
# Laysan Teal
98 (23%)
51 (12%)
286 (66%)
Because birds can fly from wetland to wetland
much faster than observers can walk between them, it is possible for a Laysan Teal to be
observed more than once during a resight survey. Identifying individuals via color bands
enabled us to estimate the frequency with which this occurs. On 61% (26 of 38) of surveys
individually marked birds were seen at more than one site, including 16 (42%) surveys where
individuals were seen on multiple islands. Among 38 surveys on Eastern Island, anywhere from
zero to seven marked birds were seen at multiple sites. Marked birds double-counted on
multiple islands and multiple wetland
Table 5. Number of individual Laysan Teal re-sighted from
sites ranged in number from zero to
Oct 2008 through Jan 11, 2010, categorized by type of
nine. A maximum of 13% of marked
effort for that individual. All birds were re-sighted at least
birds were counted multiple times
once after banding. Some individuals were observed using
(range 0–13%, mean 2.4%, s.d. 2.9%).
two or more methods and a duck that was only seen on an
Laysan Teal also do not
remain stationary while a wetland is
being surveyed. On 35 of 38 (92%)
surveys birds flew into a wetland
during the survey, with a mean of 13.0
and a maximum of 53 fly-ins during a
survey. Similarly, on 32 of 38 (84%)
surveys birds left the wetland while
being counted, with a mean of 5.0 fly-
all-wetland count was also never seen on both re-sight
surveys and incidental re-sights, so percentages do not
total to 100%.
All wetland counts
Re-sight surveys
Incidental re-sights
# of individual ducks
Only seen
Never seen
5 (1%)
133 (31%)
29 (7%)
72 (17%)
9 (2%)
23 (5%)
16
outs per wetland and a maximum of 19 fly-outs per wetland during a single survey.
Simple count index of population
There was moderate correlation (r2 = 0.51) between the number of Laysan Teal counted
during a resight survey and the abundance estimate produced by the survey, and almost no
correlation (r2 = 0.02) between all-wetland counts and the abundance estimate from resight
surveys. With more high-quality resight surveys and accompanying population estimates, the
regression relationship between counts could be refined and, if validated, simple counts of
birds—without distinction between marked and unmarked birds—would be a faster and easier
method to produce an index of the population size. In its current form, however, the regression
model produces excessively wide confidence intervals (CI), e.g., a count of 200 birds predicts a
population estimate of between 138 and 560 birds. If future quality surveys continue to show the
same variability, it will require another 47 resight surveys (or two years at bi-monthly survey
frequency) to calculate abundance estimates (for a total of 65) reducing the 95% CI to a width of
± 100 Laysan Teal.
Fraction of marked ducks detected
Figure 3 shows the monthly proportion of marked birds detected during 2009, with most
individuals having fewer total detections from April–June during the birds‘ breeding season.
Most individuals were detected (with some exceptions) from November–February during postfledging flocking and adult
courtship flocking.
If the
0.6
probability of detection is
known then abundance can be
0.5
estimated any time of year by
dividing the number detected
0.4
by the probability of detections
(Thompson 1992). However,
0.3
our results show a weak
relationship
between
the
0.2
Chapman abundance estimates
and estimates based on the
0.1
monthly detection probabilities
(linear regression, p = 0.36, r2
0
Jan Feb Mar Apr May Jun
Jul
Aug Sep Oct Nov Dec
= 0.02), meaning Thompsonstyle estimators cannot be used
Figure 3. Monthly surveys in 2009 reveal the pooled proportion of marked
to estimate abundance.
birds (post-fledglings and adults) detected.
There was only a
single, atoll-wide evening survey meeting both accuracy and precision criteria, so the efficacy of
Horvitz-Thompson estimators based on morning vs. evening detection probabilities cannot be
tested. However across all atoll-wide surveys the detected proportion of marked birds was
different between morning and evening (Chi-squared test, Yates corrected = 31.8, p < 0.0001),
and examination of the residuals indicates that this is due to lower detection rates in the evening
(28.7% vs. 38.6%).
17
Power to detect a decline
All power calculations are based on statistical tests using a type I error rate of 0.10.
Based on the abundance estimates for 2009 and 2010, a one-sample t-test detecting a
catastrophic halving of the Laysan Teal population in a single year would be significant 97.5% of
the time. The same one-year change would be 90% likely to detect a 15% decrease. Detecting a
decline over a larger time span is more difficult. Based on the abundance estimates from 2007–
2010, a linear regression estimator would have 74% power to detect a 50% decline over five
years.
Intrinsic growth rate and carrying capacity
Using previously published and current abundance estimates (Tables 1, 2) we used nonlinear regression to fit a logistic growth curve. Figure 4 shows the growth curve fit to the
available abundance estimates. The parameters of the model are consistent with a maximum
intrinsic growth rate of λ = 2.1 [P(λ ≤ 1 = 0.0534)] up to a carrying capacity of 603 birds [P(K ≤
0) = 0.0278, 95% CI = 161–1045]. The model predicts that the maximum growth rate to date
occurred during 2008, but in the past few years the population may have begun to approach the
carrying capacity. Additional resight surveys in 2010 are needed to provide supporting data for
2010 pre-breeding preliminary total estimates. If the population has not reached carrying
capacity and is released from botulism mortality, then the growth rate and carrying capacity
estimates will change with further data.
DISCUSSION
MANAGEMENT GOALS
The first goal requires
effort to enumerate the Laysan
Teal population. However, as
described previously, a simple
count will not necessarily
Laysan Teal abundance on Midway .
Refuge managers at
Midway have two nonoverlapping monitoring goals
for the Laysan Teal population.
The first goal is to track the
status and annual trend of the
abundance of Laysan Teal. The
second goal is to detect and
determine the magnitude of any
potentially catastrophic die-offs
such as the Echinuria and
botulism epizootics in 1993 and
2008, respectively, on Laysan
and Midway islands (Work et
al. 2004, 2010).
700
600
500
400
300
200
100
0
2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Estimate
Logistic growth model
Figure 4. Logistic growth curve fit to the Laysan Teal post-fledging
abundance estimates reported in Table 2. The growth curve shown is
consistent with an intrinsic maximum reproduction rate (λ) of 2.1 and
a carrying capacity (K) of 603 birds. The 2007 population estimate
includes adult birds from radio-tracking data in late 2007 and marked
post-fledglings. The 2008 estimate is an estimate of adults only as
there were no resight surveys conducted to estimate the post-breeding
population size in 2008.
18
provide a valid index of the total population of Laysan Teal and has low precision that will vary
throughout the year (Figure 3). Mark-recapture methods use the observed proportions of marked
and unmarked birds to infer the total population size and provide an estimate of true abundance.
Historically, the Laysan Teal has been susceptible to catastrophic declines due to disease
or introduced mammals. The dramatic fluctuations seen in Laysan Island population estimates
(Seavy et al. 2009, USFWS 2009) demonstrate the importance of the Refuge‘s second goal of
continuous monitoring throughout the year to detect the effect of disasters such as botulism
outbreaks or environmental catastrophes such as tsunamis and hurricanes.
In addition to the two Midway Atoll refuge goals, the recovery criteria set forth by the
U.S. Fish and Wildlife Service must be met both to downlist the species designation of Laysan
Teal from endangered to threatened and also to provide benchmarks of recovery and species
status (USFWS 2009). The Revised Laysan Duck Recovery Plan monitoring criteria require
that:
 The Laysan Island population remains at roughly 500 birds over a period of at least 15
consecutive years.
 At least 1,800 potentially breeding birds exist in a stable or increasing population (for ≥
10 consecutive years) on a combination of predator-free Northwestern Hawaiian Islands
(including Laysan Island and Midway Atoll) and at least one predator-controlled site in
the Main Hawaiian Islands.
In order to remove the species from the endangered species list entirely (i.e., to delist it), Laysan
Teal must be stable or increasing (as monitored over 15 consecutive years) in five or more
populations consisting of at least 3,000 potentially breeding adults (≥ 500 per population). These
populations, existing on a combination of predator-free Northwestern Hawaiian Islands
(including Laysan Island and Midway Atoll) and at least two predator-controlled sites in the
Main Hawaiian Islands, should be self-sustaining, requiring only minimal monitoring and
management of threats (e.g., epizootics, catastrophic declines; USFWS 2009). A new population
viability analysis (PVA) may be needed to evaluate if population sizes listed in the recovery plan
are considered viable in the face of climate change (Reynolds et al., in review).
BEST ESTIMATES
Power analysis
A true power analysis requires multiple years of abundance estimates before it is possible
to detect a trend. A minimum time period is at least five years, but that will depend upon the
variation in the estimates (Elzinga et al. 1998). Beyond normal population fluctuations and
sampling variation, the amount of ‗noise‘ will depend upon whether or not the population has
stabilized or is still increasing to carrying capacity and whether or not botulism epizootics
continue to make an impact. With additional yearly estimates to establish population trends, it
will be possible to distinguish between the biological variation and sampling variability and to
calculate the survey precision (White & Burnham 1999). With the current dataset we cannot
distinguish between natural variation and sampling error, so our power calculations are limited to
simple (non-auto correlated) regression (known to under-estimate power; Elzinga et al. 1998) or
a single-point change via t-test.
19
Mark-recapture likelihood models
Abundance and survival of Laysan Teal on Midway Atoll could be estimated using an
open mark-recapture model such as the Cormack-Jolly-Seber (CJS; Seber 1965, 1982; White &
Burnham 1999; Williams et al. 2002). Sampling designs estimate births and deaths and require a
minimum of three intensive capture occasions, but there are drawbacks to this model. CJS study
designs would require skilled endangered species biologists to capture and handle the Laysan
Teal, and it might be undesirable to disturb an endangered species to the extent of attempting to
capture most individuals every year. Finally, annual capture surveys are unable to detect a
catastrophic event as it happens; a massive die-off due to a hurricane or epizootic could only be
detected after the event when the resulting abundance estimate is calculated.
Simple index tracking
The minimal effort to detect a catastrophic event such as an epizootic will require regular
efforts to survey the Laysan Teal. Such events can happen quickly, therefore some measure of
abundance is needed a short time before and after the event to pinpoint exact time and magnitude
of the population decline. A count of all wetland habitats could serve as a simple index of
abundance. We know that Laysan Teal behavior dictates that the simple count will naturally
vary throughout the day and year (Figure 4) but a sharp decline of a standardized index count
may indicate a potential die-off and trigger a more intensive survey effort (see Seavy et al. 2009).
Without calibration of an index to an abundance estimator (LP or CJS mark-resight or recapture) and a longer time series, a simple index would be unable to provide an estimate of
Laysan Teal abundance or other needed demographic parameters identified in the revised
Recovery Plan (USFWS 2009).
Hybrid methods
By using color leg bands to identify individual Laysan Teal, the detection history of each
bird can be used to estimate abundance and other demographic parameters such as intrinsic
growth rate (λ), survival, and detection probability. A CJS model (Seber 1982) uses banding and
re-capture information to estimate abundance, and a multi-state Barker model (Barker 1997) that
includes capture, recapture, resight, and carcass recovery information about marked birds is most
likely to be useful. Simpler models require fewer years of observations (with a minimum of
three years for the CJS model and four years to estimate annual survival, re-capture, and resight
statistics with a Barker model).
Effective population growth rate (λ) can be estimated with a likelihood model. Data must
be collected for at least another three years in order to fit such a model, with at least 20% marked
birds in the population and intensive resight effort—either intensively over a few months every
year or gradually throughout the year (the current protocol). Surveying throughout the year
allows managers to pinpoint population change in time. This is especially useful for tracking
breeding phenology, detecting Refuge-wide disease events, and observing and collecting
carcasses. However, if resight protocols were changed and resight data collection were
concentrated to one time period, November through February would be the best months for
surveying since 2009 surveys had higher detection probabilities and low mortality during these
months (Figure 4).
20
Mark-recapture model data collection
Mark-recapture models are dependent upon exact identification of individuals, so
increasing the accuracy and rate of detection would improve the current protocol. One way to do
this is by using experienced wildlife biologist or bird watchers familiar with the band colors and
codes used at Midway Atoll and capable of reading bands quickly and accurately, and recording
data efficiently. Strategies to improve detection will improve data quality. For example,
perching logs could be placed near or over wetlands encouraging birds to remain out of the water
where their bands can be more easily seen. Observation towers and blinds built near wetlands
provide surveyors with better angles to observe birds without spooking them into the water
where their leg bands become concealed. Improving detection probabilities in these ways may
reduce the incidental resighting effort required, improve estimates, and reduce the number of
surveys needed to validate an index count.
Lincoln-Petersen style estimates
Until enough data have been collected to fit mark-recapture likelihood models,
abundance can be estimated via simpler Lincoln-Petersen style mark-recapture estimates, as we
have done in this report. In order for these estimates to be accurate and useful, standardized
resight surveys must detect a large number of birds with known marked or unmarked status—the
greater the number of individuals re-surveyed (resighted), the greater the accuracy and precision
of the abundance estimates (Chapman 1951).
Importantly, LP estimates assume that the number of marked animals is known. As
detailed below (Appendix 1), this assumption was violated, and we have compensated by
estimating the number of marked birds estimated alive (MEA) as described in Appendix 2. An
accurate estimate of the number of marked birds depends upon frequent and regular resights of
marked birds both to confirm that they are still alive and to establish the distribution between
detections for individual birds. The effect of missing or infrequent resight data on population
size estimates can be seen in Table 1 (p. 16) for the 11 Jan 2010 estimate. As explained in
Appendix 2, using the conservative (50th percentile: 175) versus the less-conservative (90th
percentile: 268) estimate of the number of marked birds changes their corresponding abundance
estimates from 309 to 473. It is clear that less stringent standards for resight data can have an
inflationary effect on population size estimates.
LP-style estimates require that all individuals have an equal probability of detection. For
birds on Midway this is unlikely to be a problem if marked birds are as likely to be detected as
unmarked birds. However, if marked birds, because they are individually distinguishable, are
less likely to be double-counted than unmarked birds, the number of unmarked birds will be
inflated, resulting in a positive bias to the estimate. Observers must strive to count marked and
unmarked birds as carefully as possible, without double-counting either category. Since 17% of
marked individuals were missed during the standardized resight survey (Table 5), an individual‘s
detection might be improved during resight surveys if all wetlands were included in the survey
route, or if incidental resighting effort continued.
In some resight surveys, as many as 20% of birds counted were recorded as having an
unknown banding status because they were swimming with their legs concealed or flew out of
the wetland before they were identified. In this analysis, rather than ignore these birds, we
assume that unknown status birds occur in the same proportions as the known status birds (i.e.,
21
ratio of marked/unmarked individuals). We recommend that at least 90% of observed birds have
known status, so observers must do their best to determine banding status for all birds.
Experienced observers and the physical interventions described previously (duck perches or
observation towers) will aid in determining marked/unmarked status. Observer experience
improves accuracy by minimizing disturbance, since loafing birds often become swimming birds
or ―fly-outs‖ when disturbed.
A large fraction of the Laysan Teal population (40%) must remain marked (Robson &
Regier 1964) to produce accurate estimates with a Lincoln-Petersen style estimator. At least
twenty percent of the population should be marked for accurate and precise maximum likelihood
(i.e., CJS) models (Robson & Regier 1964). In 2009, 68% of the post-fledging population was
marked, meaning the population could increase by 50% before diluting the current pool of
marked birds. It is not necessary to band new birds in 2010, but it is possible that banding may
be needed by fall 2011 or 2012, to preserve the proportion of marked birds if birth and death
rates are high. However, to maintain the current marked population, birds with worn bands
should have their bands replaced as soon as possible after discovery (with the exception of hens
with ducklings whose bands should be replaced only after fledging young). If a population index
can be validated using data from the marked birds for several years, population trends may be
detected using simple counts, and marking new birds would not be needed.
Indices
A simple count of Laysan Teal does not currently serve as a useful index of abundance.
If the current relationship between index and abundance remains the same, then collecting more
data will make the linear regression model more useful. The continuously refined regression
model will allow input of a simple count and produce an interval estimate for the corresponding
LP abundance estimate (the Excel spreadsheet described in the Statistical Analyses section is
available upon request).
MONITORING STANDARDS
Power
As mentioned above, the current LP population estimates are highly likely to detect a
catastrophic reduction of half the population within a single year. A more subtle 50% decline
over ten years would be more difficult to discern, detected only 75% of the time.
As monitoring continues and annual population estimates are generated, more
sophisticated power models will account for the effects of temporal correlation, population
growth, and epizootics. These more sophisticated models will allow a calculation of minimum
effort and survey intervals to meet specific monitoring goals. Humbert et al. (2009) recommend
at least a ten-year span of data to properly fit these models.
Continuous resights
The estimate of the number of marked birds available using LP methods depends upon
regular resight surveys with a high proportion of marked birds detected and identified. Even
though detectability varies throughout the year, standardized resight effort is needed to establish
which individuals are available to be counted for LP estimates of the population. Regular resight
22
surveys will also allow regular abundance estimates to be calculated in order to detect and
estimate the magnitude of catastrophic events in the population.
All-wetland counts and incidental resights
Since the total birds counted during resight surveys is correlated with population
estimates, it follows that all-wetland counts may be discontinued or ‗merged‘ with resight
surveys, if it is possible to use resight surveys as a population index. If so, it is also important to
maintain the same number of incidental resights or include all of the wetlands in the resight
survey. If this is not possible, then at least some of the discontinued all-wetland survey effort
should be redirected to a less intensive incidental resighting effort, especially if the large
proportion (38%) of incidental resights was due to the intensive resight effort by dedicated staff
during the pilot study.
SUGGESTIONS FOR MONITORING
Continue bi-monthly standardized atoll-wide resight surveys.
Conduct standardized atoll-wide resight surveys in the morning rather than evening.
Resight surveys should be conducted by dedicated staff or trained volunteers skilled at
bird-watching and at data collection. Observers must be familiar with these monitoring
protocols, familiar with the color and banding codes used at Midway Atoll, and will
require several weeks of practice surveys with bird ID confirmation (ID data validation).
Training should be provided by a biologist experienced with endangered Laysan Teal
monitoring at Midway. Data collected by inexperienced observers should not be used to
estimate population sizes since there is a high risk of further violating model assumptions
(see Appendix 1 for violations to assumptions 3, 5, and 6). Misidentified birds also
produce inaccurate MEA estimates and unreliable population estimates.
Worn bands should be replaced and illegible bands should be identified immediately so
that MEA estimates are not biased.
If the population continues to grow or a catastrophic event kills a large number of marked
birds, band additional birds as needed to maintain a 40% marked rate in the population
and maintain the accuracy of LP-style estimates. As few as 20% marked birds is useful
for validating a population index and for precise estimates in some (open) likelihood
models. Most CJS designs require birds to be marked every year. Less than 20% marked
is not useful for accurate or precise estimates, especially for small population sizes like
those of the Laysan Teal.
If survey effort needs to be reduced due to limited skilled staff, cease the all-wetland
count but redirect some of the effort to collect more supplemental/ incidental resights and
modify the resight survey to include all of the wetlands. Incidental resights could be
collected morning or evening.
At least two additional years are needed to validate a survey index from direct counts.
There would be advantages to converting the current data entry/storage platform from the
spreadsheet-organized Microsoft Excel to a relational database, such as Microsoft
Access. In addition to consolidating all the various data (marking, resights, band
recovery, and survey results) in a single location, the relationships can be leveraged to
improve accuracy and efficiency. For example, the process of looking up a bird‘s identity
based on the observed color bands could be automated, or the data entry form could flag
23
an error if a resight is entered for a bird already listed as dead. Birds found dead should
be updated in a continuously revised resight reference for an accurate MEA.
With a new proposal or scope of work between the USFWS and the USGS, the USGS
could update the 2010 abundance estimate and/or convert Microsoft Excel data files to an
Access database.
24
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Reynolds, M.H. 2002. The foraging ecology, population dynamics and habitat use of the Laysan
teal (Anas laysanensis). PhD, Virginia Polytechnic Institute and State University,
Blacksburg, VA.
Reynolds, M.H. & Citta, J.J. 2007. Post-fledging survival of Laysan ducks. Journal of Wildlife
Management. 71:383–388.
Reynolds, M.H., McGowan, C., Converse, S.J., Mattsson, B., Hatfield, J.S., McClung, A.,
Mehrhoff, L., Walters, J.R., & Uyehara, K. in review. Trading off short-term and long-
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term risk: minimizing the threat of Laysan Duck extinction from catastrophes and sealevel rise.
Reynolds, M.H., Seavy, N.E., Vekasy, M.S., Klavitter, J.L., & Laniawe, L.P. 2008.
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Reynolds, M.H., & Work, T.M. 2005. Mortality in the endangered Laysan Teal Anas
laysanensis: conservation implications. Wildfowl 55:31–48.
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Amer. Fish. Soc. 93:215–226.
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26
APPENDIX 1. ASSUMPTIONS OF LINCOLN-PETERSEN MODELS AND THEIR
VIOLATIONS IN SURVEYS OF LAYSAN TEAL ON MIDWAY ATOLL
Assumptions of Lincoln-Petersen style estimators (Skalski et al. 2005)
Assumption
1. The number of marks in the
population is known
2. The population is closed
3. All animals have the same probability
of being caught or sighted
4. Marking does not affect future
detection
Status
Solution
Violated
Number of marks is estimated
Violated
Marks are estimated on the date of the
resight survey; survey data is used only
during periods with low mortality and
low/no births
Not violated
Not violated
5. Animals do not lose their marks
Not violated
6. All marks are correctly reported
Violated
Birds with temporary bands are considered
to be unmarked
Unknown status birds are assumed to be
marked and unmarked in the same
proportions as known birds.
Assumptions three and four are very likely to be met, but the first two assumptions of LP
style estimators are violated during Midway surveys: the number of marked birds is not known
exactly and the population is not closed between the time of marking and the time of the
secondary survey. We attempt to accommodate these violations by using the frequency of
captures and band resights (which take place during resight surveys) to determine whether or not
a bird is still available to be counted according to criteria and methods described in Appendix 2.
The adult population approaches geographic and demographic closure over the period of several
months after the breeding season and botulism outbreaks. There is no immigration or emigration,
and adult mortality was typically low when birds were radio tracked on Midway (0.08, 95% CI
0.02–0.17; Reynolds et al. 2008) and adult mortality was also typically low on Laysan Island
(0.001–0.208; Reynolds & Citta 2007). The closure assumption is less likely to be violated for
surveys taken during periods when mortality is relatively low. Figure 3 details the number of
marked carcasses recovered, by month, during the course of this study.
Assumption 5 states that birds do not lose their marks and is not violated in the Midway
surveys of Laysan Teal. One hundred five birds were originally given temporary color bands,
intended to fall off after an unknown short length of time. Many of these birds were later recaptured and given permanent bands. For purposes of the LP population estimates, birds that
have temporary bands are included in the unmarked category. If temporary bands were not
27
distinguished from permanent bands as described in survey protocols, then the assumption would
be violated.
Assumption 6 is violated in most Midway surveys because the marked/unmarked status
cannot be determined for some birds (e.g., leg bands on swimming birds). We accommodate this
violation by assuming that unknown-status birds are marked or unmarked in the same proportion
as those of known-status birds. This is an assumption; it would be best if there were no unknown
birds, and in surveys where a significant portion (> 10%) of birds are of unknown status the
results should be interpreted carefully and supported with additional surveys.
Only marked, post-fledging birds are used in the LP estimator, and for the purposes of
these survey estimates, young-of-year are included beginning in the month of December when
survival of fledglings may stabilize. Note that this consideration deviates from the usual, normal
definition of an adult, second-year (SY) bird as one that has survived an extra month into the
January following its hatch year. Because of this inability to distinguish age classes, estimates
calculated in December through January are actually of the post-fledging abundance (of the
previous year) and will overestimate the number of breeding adults. Surveys in August–
November are likely to violate closed model assumptions if botulism is ongoing, however, they
are useful for obtaining resights and for establishing a baseline for validating an index from
standardized counts.
Number of duck carcasses found
25
20
15
10
5
0
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Figure 3. Total known mortality of marked Laysan Teal, by month from
4 Dec 2004 to 14 Nov 2009. These numbers only include marked birds
whose bands were recovered from the carcasses. All carcasses recorded
in the month of August were recovered in 2008 and 2009 during
botulism epizootics. The spike in May is due to 11 carcasses recovered
due to an unusual human hazard in 2009 (problem was removed and
unlikely to reoccur); the other two May carcasses were from 2006.
December and February had very low to no mortality detected.
28
APPENDIX 2. ESTIMATING THE NUMBER OF MARKED LAYSAN TEAL
AVAILABLE TO BE COUNTED: MARKS ESTIMATED ALIVE (MEA)
Lincoln-Petersen abundance estimators were designed for studies with short intervals
between the original marking period and the later re-survey of marked and unmarked animals
and assume that the number of marked animals in the population is known (Lincoln 1930). The
population is assumed to be closed (no mortality, birth, immigration, or emigration) during that
period. Immigration and emigration do not occur on Midway, but mortality does occur so we
must estimate the number of birds still alive to be counted during a resight survey. We refer to
this as the marks estimated alive (MEA).
On Midway Atoll Laysan Teal were marked during the three years prior to this study.
Resighting of individual birds is conducted regularly, and most birds are seen frequently (median
interval eight days). However, if a carcass is not discovered, and a bird is not seen, its status
(dead or alive) is not known and must be estimated. Banding records and resights of individuals
determine the last date a bird was known to be alive. If the last known alive date is earlier than
the date of the survey being analyzed, the possibility exists that the bird has died in the interim
and is not available to be counted during a survey. If a bird is counted as not available for a
survey on date "D," it is possible that it could be resighted later. We would then know, after the
fact, that the bird was available on date D, so our estimate for the number of birds on date D
would retrospectively change very slightly (e.g., one additional marked bird would reduce the
Chapman estimate of abundance by fewer than three birds under current conditions (around 400
birds) with > 50% marked and > 200 birds resighted on each survey).
How long should we wait, after a Laysan Teal is last known to be alive, before it is
counted as missing? That amount of time will depend upon the behavior of the individual, and
we can use the previous record of detections for that bird to determine how long to wait. If a
bird is shy and seldom seen, the intervals among detections will be long, so we will wait a longer
time before declaring it missing. Likewise if an outgoing bird that is seen every day disappears
for a week, we suspect the worst. By looking at each bird‘s individual distribution of intervals
between re-detections and choosing a quantile of the distribution we can determine the maximum
time to wait before a bird is considered missing. In this report we present results using the more
conservative 50% quantile (or median) interval length and the 90% quantile, the interval length
where only ten percent of the observed intervals for that bird are longer.
Because a Laysan Teal that is still living always has a chance of being resighted while
resight effort continues, the further in the past a survey was conducted the more confidence we
have that a bird declared missing is dead, in general giving us greater confidence in population
estimates calculated for older surveys than our confidence in more recent surveys. For example,
using Table 1, the median interval on the 11 Jan 2010 survey of 488 marked birds reports that
only 60 (12%) were known to be dead and 264 (54%) were considered missing. Using the 90th
percentile of resight intervals only 127 (26%) were considered missing; this changes the
estimated abundance from 248 to 152 birds. By contrast, in the 23 Oct 2007 survey, switching
from the median to 90th percentile of detection intervals changes the number of missing only
slightly from 7 (6%) to 5 (4%) of the total number of marked adults—a negligible amount with
29
little effect on the population estimate. Additional resight surveys in 2010 will allow us to
increase our confidence in determining the survival status of birds early in the year.
There are two additional issues to be considered when determining the length of time
before a bird is declared missing. Some birds on Midway were given temporary color bands.
Intervals among resights of temporary bands were not used to establish the distribution of
intervals among detections. Because temporary bands are expected to fall off, leaving the bird
unidentifiable by casual resight, a bird might vanish from the resight records when only its bands
were gone, not the individual. This omission is consistent with the established protocol of
identifying and omitting temporary bands during surveys.
In late 2009, some Laysan Teal were marked too recently or resighted too infrequently to
establish a distribution of intervals among detections for that individual bird. For birds with
fewer than ten intervals in their detection history we used the distribution of all intervals from all
birds in the dataset as their detection history. Future resights may increase an individual's
number of detection intervals to ten or more, allowing its individual distribution to be calculated.
This change will not affect the results of historical surveys, except in the case described above
when a bird that was once declared missing is later discovered to have been alive. These cases
should be carefully confirmed with positive field identification.
30
APPENDIX 3. MIDWAY ATOLL LAYSAN TEAL RESIGHT SURVEY PROTOCOL
INCIDENTAL RESIGHTS
An Incidental Resight is any band combination identified from a Laysan Teal (this protocol also
uses ―Laysan Duck‖ or LADU interchangeably) other than during an official (timed) Resight
Survey. Incidental resight information is valuable data used to determine the identification and
number of marked birds available to be counted. Data can be transcribed into a Laysan Teal
Incidental Resight Data Book. This data book or resighting data should be accessible in the
USFWS office. Include the following data:
Date, Time
Observer
Color Band and Color Band Symbol Right Leg (RL) and Left Leg (LL)
FWS or metal band (Right Leg or Left Leg and number), if not read DNR or ―did not read.‖
Most birds can be identified by their color band, and it is not necessary to read the aluminum
(AL) band unless the color band is missing or too faded.
Age Class of bird, if known (Table 6; L—duckling, AHY—after hatch year, ASY—after
second year)
Sex of bird, if known1
Location of sighting
Comments on band condition (worn or faded), occurrence of ducklings, injuries
OPTIONAL Behavior (was it sleeping, feeding)
OPTIONAL Any associated ducks or mates and the band combination (ID) of the other
duck(s)
1
Female Laysan Teal have a paler bill, often with small ―freckles‖ at the base. The legs are dull orange, and the
plumage may be lighter brown than males. Males have a black saddle on the bill with the sides of the bill deep
green. The legs are often bright orange, and males may have an upturned curled tail feather. The plumage on the
head may be darker brown.
31
Table 6. Laysan Teal age class characteristics for Midway Atoll (Note Stage Ia–Ib ducklings are
very susceptible to mortality related to human disturbance).
Days Old
1-6
7 - 12
13 – 18
19 – 25
26 – 35
36 – 45
46 - 60
Flying 52 -63
Flying
> 63 – 73
Hatched that
year > 73
Hatched
Previous Year
Generic Adult
> 360 days
Plumage Class
Description
Bright ball of fluff; down bright and new; rounded
Ia
body; neck and tail not prominent
Ib
Fading ball of fluff; down fading
Gawky downy; down color and pattern faded; neck
Ic
and tail prominent; body long and oval
II a
First feathers; feather begins on sides of body
Mostly feathered; side view shows one half side and
II b
flank feathered; down remains on nape of neck, back
and/or rump
Last down; little down on rump, neck, or back;
II c
sheaths visible on erupted primaries, no eye ring
Feathered flightless = no down visible; flight feather
III a
out of sheath but not fully developed
III b
Flies; still with brood
Flies and more independent; small amt. white
III c
plumage over eye; no sexual dimorphism
Independent; > 73 days until Jan 1 of following year.
HY / Fledgling Small; eye ring; glossy plumage; some sexual
dimorphism evident
Glossy plumage; small eye ring; plumage often
SY
distinguishable from Jan 1 until about March
AHY
Any mature adult of unknown age
At least 50% plumage on head is white (general
ASY
guide-line for adults of unknown age)
Possible Band Numbers, Letters, and Symbols
Use the following codes to record band colors and combinations or write out the colors and the
color of symbols on the color band. Please examine the string of sample color bands in the
biology office before attempting to record band resights.
Numbers: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
Letters: A, C, E, F, H, J, K, M, N, P, R, S, T, U, W, X, Y
Letters with Numbers: C1–C9, X1–X10
Two Letters: WA-WY, XA-XY
Symbols: *, #, $, <, >, ?, \ , /, &, +, Grooves: single (e.g., R/WG) or double (e.g., GN/2WG)
Permanent Bands
Current permanent color band codes on Midway (Apr 2009):
AL = Federal aluminum
BK = Black with or without white letters, numbers or symbols (BK temporary bands without
numbers or symbols also occur)
BKY = Black with yellow numbers, letters, or symbols
BR = Brown with white numbers, letters, or symbols
32
B = Blue (royal blue) with white numbers, letters, or symbols (Light Blue (LB) bands or Dark
Blue (DB) bands without symbols are also deployed) – if unfamiliar with codes please
write out the word Blu or Blue to distinguish from Black, or Brown
BY = Blue (royal blue) with yellow numbers, letters, or symbols
GN = Green with white numbers, letters, or symbols (Dark Green (DGN) and Light Green
(LGN) temporary color bands without symbols are also deployed)
GY = Grey with black numbers, letters, or symbols—if unfamiliar with codes write out the word
of the color and do not use the code GR which is confused with green
O = Orange with or without black letters, numbers, or symbols
R = Red with or without white letters, numbers, or symbols (be aware of Purple (PU) and
Fuchsia (FU) temporary bands that can be confused with red)
W = White with or without black letters, numbers, or symbols
WM = White band with mint green letters, numbers, or symbols
Y = Yellow with black numbers, letters, or symbols (Y temporary bands without numbers or
symbols also occur)
Bands with colored grooves or stripes are recorded as the band color, and the number and color
of grooves (e.g., Yellow with 1 Black Groove is coded as Y/BKG; Green with 2 White grooves
is coded as GN/2WG).
Temporary Bands
Temporary color bands were deployed on young Laysan Teal in 2007 and rehabilitated birds
during the botulism epizootic in 2009. These typically have no symbol and no AL band. Colors
include all listed above plus: hot pink (HP), fuchsia (FU), purple (PU), light green (LGN), dark
green (DGN), light blue (LB), dark blue (DB). Many have fallen off so you may see a color
band on only one leg. It is important to try and specify temporary bands versus permanent
bands, especially those on birds that may have lost one of their temporary bands. Temporary
bands are coded using lower-case letters followed by ―-temp‖ (e.g., hot pink temporary is coded
as hp-temp; dark green temporary is coded as dgn-temp). These birds should be given
permanent bands to be included in population estimators.
Aluminum Only
There are birds that only have an AL band with no color band. Please try to identify the sex of
the birds and read the numbers on these bands for a positive ID. Use a spotting scope to reduce
disturbance to the birds, especially during duckling season. Do not approach the birds closer
than 30 m unless you are doing a resight survey or a botulism carcass search. Never approach a
hen with ducklings. Leave the area quickly if a hen with young ducklings approaches you. It is
ok for birds without ducklings to approach observers closer than 30 m especially during the nonbreeding season. Due to possible color band loss or unrecorded removals, there may be more
birds with ―AL only‖ than noted in the Resight Reference (the reference file for all bird bands
used). Always attempt to read all AL only numbers.
Band Discrepancy
If there is a band combination that has been resighted that is not in the Resight Reference (RR),
record the bird as observed, make a note of it and try to resight the bird again. Some band
combinations may be incorrect in the RR because they might have been transposed accidentally
33
during banding. After several sightings of the same combination, the RR should be corrected
(notify michelle_reynolds@usgs.gov, Leona Laniawe, or John Klavitter). List the date and
person that reported the observation from the field.
34
PROCEDURE FOR STANDARDIZED RESIGHT SURVEY OF ALL WETLANDS
The accuracy of a population estimate or population status index will depend largely on the
variation in counts (detection probabilities). Probability of detecting wetland-dependent birds
varies with time of day, diurnal patterns, weather conditions, and possibly seasonally. Thus,
pilot surveys will identify the optimal time to conduct surveys at a site to maximize detection
probability. Frequent surveys (weekly) are recommended to evaluate the proportion of the
population likely to be observed during survey efforts, and confirm the survival and the number
of marked birds in the population. In addition to the Standard Resight Survey, a timed atoll-wide
All-Wetlands Count (this survey will be discontinued beginning in 2010) will help determine the
proportion of birds we might be missing on the Standard Resight Survey. Simultaneous surveys
of both Sand and Eastern islands are needed for a population estimate and for a more complete
count and to reduce the frequency of double counting unmarked birds. The Standard Resight
Survey of all wetlands (Resight Survey, combines the Standard Resight Survey with the atollwide All-Wetlands Count into one survey), should be conducted bi-monthly only by experienced
wildlife observers with a quality zoom spotting scope and good binoculars. If volunteers
participate, volunteers should be accompanied by an experienced Midway bird/wildlife biologist,
or have bird watching experience and undergo numerous training sessions before participating in
time-dependent surveys. All sightings should be confirmed using the Midway Resight Reference
list (page 48, Fig. 7) after returning from the field.
Materials Needed:
Sample Color Bands (check these out in the office before conducting any resights)
Garmin GPS for sunrise and sunset times
Time Piece
Tally Counters for counting flock sizes, banded, and unbanded birds
Resight Data Clipboard and Data Sheets on Rite in the Rain® paper
Spotting Scope, Tripod, and 10x40 Binoculars
Pencils
Footwear that can get wet
Survey Map/Survey Route (Each survey is randomized to avoid spatial & temporal bias)
3 hours per Sand Island Resight Survey (15 minute grace period)
2 hours per Eastern Island Resight Survey (15 minute grace period)
Bike or Golf Cart (low density albatross season)
Procedure
1. Check Garmin GPS (accessories menu) for exact sunrise/sunset time before each survey.
Fill in this time on the data sheet before conducting survey. Example data sheets are
presented in Attachment 1. On Sand Island, begin morning surveys at sunrise or evening
surveys 3 hours before sunset. On Eastern Island, begin morning surveys at sunrise or
evening surveys 2 hours before sunset if camping; or 2 hours 30 minutes before sunset if
traveling by boat to allow time to return with sufficient daylight. The allotted time for
the Resight Survey is 2 hours on Eastern Island; 3 hours on Sand Island. Surveys may
not exceed the allotted time by more than 15 minutes—aim to be efficient and finish on
time.
35
2. Much of the Laysan Teal population resides on Eastern Island. Two observers are
needed to conduct a simultaneous survey with the Sand Island Survey. Simultaneous
atoll-wide surveys are needed to estimate the population size. If sea conditions are
unsuitable, reschedule the Resight Survey. If a survey has been started and cannot be
finished because unsuitable weather conditions arise, the survey must be rescheduled and
repeated in its entirety. Resights read prior to cancellation will be included as incidental
resights. Plan on conducting one weekly Resight Survey and/or atoll-wide All-Wetland
Count (or two Resight Survey and All-Wetland Counts per month). If a Resight Survey
cannot be completed in a week because of persistent unsuitable weather, attempt to
conduct the survey the following week (a count and a resight survey during the same
week). If two skilled resight observers are not available, the survey should be postponed
until a second skilled observer is available. As a last resort, if only a single observer is
available for > two weeks, a single skilled observer should survey Eastern Island on the
first morning and Sand Island the second morning.
3. Check the hard copy of the previous survey‘s Start Locations and Direction of Travel
Table (Attachment 2) and record the date of the survey‘s randomized start. For the Sand
Island Resight Survey, eight random survey numbers have been assigned to specific
starting locations and direction of travel at 13 different wetlands. An example of the
clockwise order of the Resight Survey route is: Catchment Basin → Mauka-Makai, →
Ironwood, → Aviary,→ Rusty Bucket, → Radar Hill Seeps, → Ball Field Seeps, → Fuel
Farm, → Brackish Pond, → Sunrise, → Communications, → Parade, → and R2. For the
Eastern Island Resight Survey, six random survey numbers have been assigned to the
three wetlands using different randomized orders. Refer to the map for survey travel
routes and familiarize yourself with the route in the field before attempting to conduct a
survey (Attachment 3). Follow the route outlined in the prescribed direction.
4. Aim to arrive at the start location five minutes before the official start time. Record
weather variables as soon as you arrive. Review the rain scale (Table 7) and Beaufort
wind scale (Table 8, page 46) if you are not familiar with them. If weather conditions
change, record the range of conditions during most of the survey period. Reschedule the
survey in steady heavy rain, winds ≥ 6 or storm conditions. Use the 15 minute grace
period to stop survey during squalls of short duration.
Table 7. Rain scale for data entry.
Notation
0
1
2
3
4
Description
no rain
mist (fog)
light drizzle
light rain
heavy rain
5. Record your initial arrival times at each wetland and then count all post-fledgling birds,
note independent juveniles (HY) if they are distinguishable (June–August).
6. Rapid transitions between wetlands are needed. The amount of time spent at each
wetland will depend on the number of birds using it, your efficiency in reading bands,
your travel time between wetlands, and the albatross density.
7. Approach wetlands with a low profile, slowly and quietly as birds will jump into the
water or hide in dense vegetation if alarmed; this will obscure leg bands. Be sure to
36
record all birds that emerge, fly out, fly in, or fly by. If birds fly in or out of the
wetland, they should be tallied and included in the total count at that wetland, unless you
are able to observe the birds moving between wetlands (and then you can subtract them
to prevent known double counting). Often, birds that are flying out will be of unknown
band status. Many wetlands will require that you look for birds from two different
vantage points due to vegetation obscurity at loafing sites. Use observation towers and
blinds if available.
8. Determine if each bird is banded, unbanded, or unknown (if legs are concealed while
flying, swimming in turbid water, or too far away). Plan on getting your feet wet to read
band status at some wetlands. Surveyors may also try sitting at the edge of the wetland,
which allows the birds to relax, come out of the water, and walk on the shore where their
bands can be read. Some birds have bands on both legs; others are banded on only one
leg. It works well to count them all first, check for band status, record that, then begin
reading and recording the color bands. Often you will need to count them all again at the
end if birds have emerged during your count. Because of the time constraints of the
survey, you will need to be very efficient. Recruit a qualified scribe if there is an
interested person available that has some wildlife counting experience. Because running
the survey efficiently requires practice, dedicated observers are needed to conduct
surveys.
9. If duckling broods and associated hens are observed, keep your distance and lower your
profile (hide). Take care not to cause brood fragmentation, prolonged alarm response, or
curiosity/distraction from the mother hens. Use a spotting scope and/or visual barriers if
hens with broods are known to occur at a wetland.
10. While en route, record any Laysan Teal you see, as well as those flying by, flying in, or
that flush from the wetlands. Include these resights in your total Post Fledgling Count if
they were sighted during the survey (start and end time limit) or after, but within the time
limit; change the end time and include the birds as survey birds. If the time limit is over
(beyond the grace period) then the birds will be considered incidental resights.
11. Enter survey totals and check resights using the Midway_Resight_Reference.xls (see
Resight Survey Data Entry and Fig. 7). Enter all unique resights with the updated date
and your initials into the Midway_All_Resights.xls (Fig. 8). Enter methods as ―Resight
Survey‖ or ―Incidental Survey.‖ Enter the survey totals in the
Midway_LADU_Survey_Summaries.xls (Fig. 11).
37
Table 8. Beaufort Scale: Specifications and equivalent wind speeds for sea and land.
Beaufort
Number
Wind Speed
Wind
Descriptor
0
Miles/hr
0–1
Knots
0–1
1
1–3
1–3
Light air
2
4–7
4–6
Light breeze
3
8–12
7–10
Gentle breeze
4
13–18
11–16
Moderate breeze
5
19–24
17–21
Fresh breeze
6
25–31
Calm
22–27
Strong breeze
7
32–38
28–33
High wind,
moderate gale,
near gale
8
39–46
34–40
Gale, fresh gale
9
47–54
41–47
Strong gale
10
55–63
48–55
Storm, whole
gale
11
64–72
56–63
Violent storm
12
73–83
64–71
Hurricane-force
Sea Description
Flat.
Ripples without crests.
Small wavelets. Crests of glassy
appearance, not breaking
Large wavelets. Crests begin to
break; scattered whitecaps
Small waves w/ breaking crests.
Fairly frequent white horses.
Moderate waves of some length.
Many white horses. Small amounts
of spray.
Long waves begin to form. White
foam crests are very frequent. Some
airborne spray is present.
Sea heaps up. Some foam from
breaking waves is blown into streaks
along wind direction. Moderate
amounts of airborne spray
Moderately high waves with
breaking crests forming spindrift.
Well-marked streaks of foam are
blown along wind direction.
Considerable airborne spray
High waves whose crests sometimes
roll over. Dense foam is blown
along wind direction. Large amounts
of airborne spray may begin to
reduce visibility.
Very high waves with overhanging
crests. Large patches of foam from
wave crests give the sea a white
appearance. Considerable tumbling
of waves with heavy impact. Large
amounts of airborne spray reduce
visibility.
Exceptionally high waves. Very
large paths of foam driven before
the wind, cover much of the sea
surface. Very large amounts of
airborne spray severely reduce
visibility.
Huge waves. Sea is completely
white with foam and spray. Air is
filled with driving spray, greatly
reducing visibility.
Land Description
Calm. Smoke rises vertically.
Smoke drift indicates wind direction, still
wind vanes.
Wind felt on exposed skin. Leaves rustle,
vanes begin to move.
Leaves and small twigs constantly moving,
light flags extended.
Dust and loose paper raised. Small branches
begin to move.
Branches of a moderate size move. Small
trees in leaf begin to sway.
Large branches in motion. Whistling heard
in overhead wires. Umbrella use becomes
difficult. Empty plastic garbage cans tip
over.
Whole trees in motion. Effort needed to
walk against the wind.
Some twigs broken from trees. Cars veer on
road. Progress on foot is seriously impeded.
Some branches break off trees, and some
small trees blow over.
Construction/temporary signs and
barricades blow over.
Trees are broken off or uprooted, saplings
bent and deformed. Poorly attached asphalt
shingles and shingles in poor condition peel
off roofs.
Widespread damage to vegetation. Many
roofing surfaces are damaged; asphalt tiles
that have curled up and/or fractured due to
age may break away completely.
Very widespread damage to vegetation.
Some windows may break; mobile homes
and poorly constructed sheds and barns are
damaged. Debris may be hurled about.
Double Counts
Birds may move during the survey. If a unique banded bird is resighted at multiple seeps/sites
during the survey, record both resights (e.g., AL/GNXA resighted at both Brackish and Sunrise).
After the survey, when completing the data form, correct for double counts by including only
one of the two or more resights in the total number of birds. During a Simultaneous Survey,
birds may move between islands. If a unique banded bird is resighted on both Sand and Eastern
38
during the survey, record the total number of double-counted unique banded birds identified
atoll-wide on the data sheet.
Temporary Bands
On the data sheet, include the number of Laysan Teal with: unique temporary bands (birds that
can be connected to a Link #; temporary bands were seen on BOTH legs), not unique temporary
bands (without Link #, only one leg was seen with a temporary band or both legs were seen with
only one temporary band), and the total number of temporary bands. Correct totals for double
counts; e.g., if bk-temp/bk-temp was recorded at both Catchment and Brackish, include one of
the two detections in the total.
Resight Survey Data Entry
All data sheets should be scanned and saved electronically as a backup copy in case the hard
copy goes missing. Data should be entered by the observer as soon as possible after completing
the survey. Timely data entry avoids data backlogs, misplacement of data sheets, and provides
an opportunity for the observer to add data to incomplete data fields and decipher illegible
writing.
There are four Excel files that will be used with Laysan Duck Resight Survey data.
They are:
Midway Resight Reference—for reference only, containing all the band combinations in
use in the Laysan Duck population and data on those individuals (Figs. 7 and 9). Data
entry in this file is not covered here.
Midway All Resights—where all the information on each resighted individual is recorded
during the Resight Survey or incidental resights (Figs. 8 and 10).
Midway LADU Band—used during bird banding. This file can be used as a back-up for
band information if the current Resight Reference file is unavailable. Data entry in this
file is not covered here.
Midway LADU Survey Summaries: Standard Resight Summary tab—overall numbers of
birds for each island and atoll-wide including times of surveys and weather conditions
(Fig. 11).
1. The first step is to enter a resight record for each banded bird that was uniquely identified
by bands during the survey. This will verify that the band was read correctly and the age
and gender were appropriately recorded. To make the entry, open both the ―Midway
Resight Reference‖ (Fig. 7) and ―Midway All Resights‖ files (Fig. 8). Check with the
Laysan Duck data manager to verify that the Resight Reference file is current with all the
latest Laysan Duck banding data updates (newly banded birds, lost bands, changed bands,
unreadable bands, and mortalities). If the Midway Resight Reference is not current, data
entry should be delayed or the data manager should enter the data using the ―Midway
LADU Band‖ file. If the Midway Resight Reference is current, use this file to search for
the identity of the bird observed. To most easily search the Midway Resight Reference,
click on the small arrow located in the lower right corner of the header row cell
containing the field you would like to search under (Fig. 9). This is typically the band
observed on either the right or left leg. If the band was read accurately on the correct leg,
the band will be found. Once found, click on the correct band and the record for the bird
39
or birds wearing this band will pop up. Use your mouse and highlight the information
contained in cells A to F, copy and paste it into the next available line in the cells under
the columns H to M in the Midway All Resights file (Fig. 10). Next, in the Midway All
Resights file type in all of the other information (date, time, etc.) pertaining to the
observation. Continue this process for all bands that were recorded during the survey.
Once all bands have been entered, save the file with a new name including observer
initials and the current date (e.g., Midway_All_Resights_MHR_19Jul2010.xls).
Figure 7. Laysan Duck Midway Resight Reference Excel file showing the header line and the first nine Laysan
Ducks currently surviving in Midway‘s population. Column A is the Midway Link # which is a unique
identifying number for each Laysan Duck. Columns B through D include the band on the right leg, band on the
left leg, and sex of the bird. Column E is the bird‘s age in 2009. Column F is the most recent aluminum
USFWS band number. Column G gives the origin of the bird, for example whether the bird was a translocated,
or founder, bird. Column H provides notes on the condition of the band, etc. Columns I and J list the location
and date the bird was last seen.
40
Figure 8. Laysan Duck Midway All Resights file showing the header line and resight entries for Midway‘s population. Column A and B are the date and time of the
observation. Column C lists the observer initials. Columns D and E are the zone and the location where the bird was observed. Column F is the habitat type. Column G
is the unique link # for the bird observed. Columns H and I are the bird‘s bands for the right and left legs. Columns J and K list the sex and age. Column L (USGS #, i.e.,
USFWS number) is the current aluminum band the bird was wearing. Column M is used for recording numbers on the aluminum band that are read by the observer.
Columns N to R are used for recording information about the observed bird‘s mate. Column S is used for comments (this is where any behaviors can be recorded as well).
Column T lists the method of surveying that was used when the bird was observed.
41
Figure 9. Using the Midway Resight Reference file to verify that a band was read correctly and locating the record for the bird. The small arrow in the lower right corner of
the header row for RLEG was clicked, allowing a search of available bands.
Figure 10. Midway All Resights file with the information pasted in that was copied from the Midway Resight Reference file.
42
2. After all of the resights have been entered and all the bird bands, ages, and
genders have been confirmed, the next step is to enter the summarized survey
data. Open the ―Midway LADU Survey Summaries‖ file. Click on the ―Standard
Resight Summary‖ tab (Fig. 11). Three separate data lines will be entered
(assuming an atoll-wide survey was completed): one for Sand Island, one for
Eastern Island, and a third Atoll Wide line, which sums the results from Sand and
Eastern. If only one island was surveyed, only one line of data is entered for that
island surveyed. For the island surveyed, the date and island are entered in
columns A and B. In columns C and D, Atoll Wide or One Island and AM or PM
are written. Observer(s) initials are typed in column E. Start and end times and
time of sunset or sunrise are entered in columns F, G, and H, using a 24-hour
clock. Weather variables are recorded in columns I to K. Starting point
(Attachment 2), starting location, and direction of survey (clockwise or counterclockwise, entered as Clock or Counter) are entered in columns L to N. Next,
follow the data sheet and enter all the information cell by cell as indicated by the
header row from columns O to BR. If there is only one island to enter, proceed
with saving the file with a new name which includes the observer initials and date
(e.g., Midway_LADU_Survey_Summaries_MHR_19Jul2010.xls). If both islands
were surveyed, continue the data entry for the second island. Once the entry is
complete, add a third row of data which will sum the information for Sand and
Eastern islands. The date will be the same as the Sand Island survey date. Record
Atoll Wide for both columns B and C. Record morning or evening survey
(column D) and observer(s) initials (column E). Sum the survey information from
the two surveys for columns AE to AZ using the computer calculator, not by
hand. Once this is finished, the file is saved as indicated previously.
Figure 11. The Midway LADU Survey Summaries file, Standard Resight Summary tab showing the
headings and cells from columns A to N. Headings and columns are not shown for O to BR.
PROCEDURE FOR PILOT ATOLL-WIDE ALL-WETLANDS COUNT
43
This survey will be discontinued in 2010. Resight surveys will be modified to
include all wetlands.
1. Twice per month, an atoll-wide All-Wetlands Count index should be conducted at
sunset or sunrise. The count must go no more than 15 minutes past the allotted
time for the data to be usable—aim to be efficient and finish on time.
On Sand Island every permanent and ephemeral wetland known should be
completed in 1 hour 45 minutes. Begin survey at sunrise or 1 hour 45 minutes
before sunset. Wetlands counted include Rusty Bucket Seep, Aviary Seep,
Ironwood Seep, Mauka-Makai, Mauka-Makai Drainage Ditch, Catchment
Basin, R2 Wetland, R2 Treatment Pools, Tarmac Pool, Communications Seep,
Parade Seep, Sunrise Seep, Brackish Pond & overflow areas, Fuel Farm,
Radar Hill Seeps, and Ball Field Seeps.
On Eastern Island: Monument, Rolando, and Sunset Seeps should be
completed in 1 hour 15 minutes. Begin survey at sunrise or 1 hour 15 minutes
before sunset if camping or 1 hour 45 minutes before sunset if traveling by
boat to allow time to return with sufficient daylight.
2. Check the hard copy of the previous surveys‘ Start Locations and Direction of
Travel Table (Attachment 2) and record the date of the survey‘s randomized start.
For the Sand Island All-Wetlands Count, eight survey numbers have been
assigned to specific starting locations and direction of travel at five different
wetlands.
For the Eastern Island All-Wetlands Count use the same series of randomized
starting locations and direction as the Resight Survey. Refer to the map
(Attachment 3) for survey travel routes and familiarize yourself with the
actual route before attempting to conduct a survey.
3. Record the following data: # total ducks, # banded, # unbanded, # unknown,
birds that fly in, fly out, and fly by and any broods/ducklings with age classes, if
known. If birds fly in or out of the wetland, they should be noted and subtracted
from the total count at that wetland.
4. Make special note of birds with temporary bands, or other bands that appear to
be falling off. After the survey has been completed, record the total number of
temporary bands observed on the data sheet.
5. Rapid transitions between wetlands are needed. Typically, there is insufficient
time to read the band combinations. This is an index to see how many birds are
using areas not included on the Standard Resight Survey, and may be a good
indicator of seasonal detection probabilities or flock behavior. A separate data
sheet is used for the All-Wetlands Count (Attachment 1).
6. If you finish the count early and there are band combinations you can read and
record (as incidentals), continue surveying until birds have been identified. End
your count at approximately 1 hour 45 minutes on Sand Island and 1 hour 15
minutes on Eastern Island. If an infrequently used wetland is skipped because of
lack of water or time constraints, mark the wetland ―not checked.‖
7. On both surveys, always be alert for sick birds, bird carcasses, hens with new
duckling broods, or birds with band injuries (i.e., swelling or debris in leg bands).
Note the ID of the injured bird, and seek assistance, if needed, to capture sick or
44
injured birds. Collect carcasses, or return to collect carcasses as soon as possible.
Avoid disturbance of hens with ducklings by maintaining maximum distance, not
approaching broods, and leaving the wetlands as soon as possible to prevent
brood fragmentation to downy ducklings.
8. Edit, total, and summarize your completed Standard Resight Survey or atoll-wide
All-Wetlands Count on the data sheet. Transcribe incidental resights into the
incidental resight book. Enter count total data within 48 hours of collection.
Atoll-wide All-Wetlands Count Data Entry
1. The first step is to enter all resight records for banded birds that were
opportunistically identified by bands during the survey as described previously
(Figs. 7–10, Incidental resights).
2. After all of the resights have been entered and all the bird bands, ages, and
genders have been confirmed, the next step is to enter the summarized survey
data. Open the ―Midway LADU Survey Summaries‖ file. Click on the
spreadsheet tab ―All Wetland Count Summary‖ (Fig. 12). For each wetland
visited during the survey, one line of data will need to be entered starting with the
date in column A and continuing to the right to include island, survey type (island
or atoll-wide), wetland location, arrival time, if water is present in the wetland,
number of banded birds, number of unbanded, number of unknown, total post
fledglings, number of broods, number of ducklings, number of hatch-year banded,
number of hatch-year unbanded, number of birds flying in, out, and by the
wetland and their totals, and finally comments are entered in column S. Repeat
this data entry for each wetland visited during the All-Wetland Count. The data
entered in the spreadsheet follows the data sheet very closely.
3. After all of the All-Wetland Count Summary data have been entered, next click
on the ―Count Conditions and Totals‖ tab from the Midway LADU Survey
Summaries file (Fig. 13). In the spreadsheet, data are summarized from all the
wetlands visited during the All-Wetland Count. If only one island is visited
during the survey, only one line of data is entered. If both Sand and Eastern
islands are visited, then three lines of data will be entered, one for Sand, one for
Eastern, and one for the Atoll where data from Eastern and Sand are totaled. Start
with Eastern Island and begin entering information from the data sheet including
the date, island, survey type (island or atoll-wide), AM or PM survey, observers,
time start, time end, time of sunrise or sunset, rain, wind, cloud cover, starting
point number, start location, end location, direction of travel, total number banded
birds, total unbanded birds, total unknown birds, total post-fledglings, total
number of temporary bands, total broods, total number of ducklings, total hatchyear banded and unbanded birds, total number of birds that flew in, out, by, and a
summary total of these, and finally notes in Column AC. Continue this same data
entry for Sand Island. A third line of data will be entered and used to sum the
data from both Eastern and Sand islands. This line of data will be highlighted in
yellow (Fig. 13). Once all of the survey data have been entered, rename the file
with observer initials and the current date (e.g.,
Midway_LADU_Survey_Summaries_MHR_05Jul2010.xls).
Figure 12. The Midway LADU Survey Summary File open to the All Wetland Count Summary tab.
45
Figure 13. The Count Conditions and Totals tab from the Midway LADU Survey Summaries file.
46
47
ATTACHMENT 1. REVISED DATA SHEETS:
SAND ISLAND LADU Standard Resight Survey of All Wetlands (3 hours)
Date:
Observers:
Time start:
Time end:
Sunrise/Sunset: _____/_____
Rain:
_(0-4)
Wind:
__ (Beaufort Scale)
Clouds:
%
Starting Point #______
Start Location:________________
Direction:_______________
Standard Atoll Wide Protocol
Post
Fledglings
Male
Female
□
Opportunistic One Island Survey □
Unidentified
Sex, Post
Fledglings
Total
Post
Fledglings
Hatch Years
(HY)
Ducklings
Banded
Unbanded
Total:
Unknown
Broods:
TOTALS
TEMPORARY bands—# of unique:_____ # of not unique:_____
Total: _______
Total # not unique ALUMINUM ONLY: ________
Total # of banded DOUBLE COUNTS—at multiple sites: ______ Atoll Wide (for simul. surveys): _____
Total # of UNIQUE BANDS during Resight Survey (check reference list, correct for dbl counts): _____
Location
Arrival Time
Depth
Total Laysan
Ducks
Ball Field
Big / Little
Fuel Farm
Brackish
Pond / &
Communications
Sunrise
adjacent
/
/
R2
Parade
Treatment/
wetland
/
/
/
/
Bnd
/
Bnd
Bnd
/
Bnd
Bnd
Bnd
Bnd
/
Unb
/
Unb
Unb
/
Unb
Unb
Unb
Unb
/
Unk
/
Unk
Unk
/
Unk
Unk
Unk
Unk
/
TOTAL
TOTAL
TOTAL
TOTAL
TOTAL
TOTAL
TOTAL
/
/
/
# LADU flew
/
in/ flew out/
flew by
/
/
/
/
/
/
/
/
/
/
/
/
Migrant
waterfowl
Location
Catchment
MaukaMakai /
Aviary
Ditch
Arrival Time
Depth
Total Laysan
Ducks
Radar
Hill
Rusty
Bucket
Ironwood
1 / 2
/
/
/
/
Bnd
Bnd
/
Bnd
Bnd
Bnd
Bnd
/
Unb
Unb
/
Unb
Unb
Unb
Unb
/
Unk
Unk
/
Unk
Unk
Unk
Unk
/
TOTAL
TOTAL
TOTAL
TOTAL
TOTAL
TOTAL
/
/
# LADU flew
in/ flew out/
flew by
/
/
/
/
/
/
/
/
/
/
/
/
Migrant
waterfowl
Total observed ducks on the move (flew in/flew out/flew by):
August 2010
/
/
47
/
48
Example of Clockwise wetlands route: Catchment, Mauka-Makai, Aviary, Ironwood, Rusty Bucket, Radar
Hills, Ball Fields, Fuel Farm, Brackish Pond & adjacent wetlands, Sunrise, Communications, Parade, R2.
Resight data sheet
Location
RLeg
LLeg
Band No.
Sex
Age
Paired?
Y/N/U
Mate ID
Notes
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
August 2010
48
49
Midway LADU Sand Island Original All-Wetlands Count (1 hour 45 minutes)
This count will be discontinued in 2010.
Date: _______ Observers:
Time start: _____ Time end: _____ Sunrise/Sunset: _____/_____
Rain:
(0-4) Wind:
(Beaufort Scale) Cloud Cover:
%
Start location _______________ End Location: _______________ Direction: ________
Standard Atoll Wide Protocol □
Opportunistic Survey □
Total number of birds observed with temporary bands:
Sand Island
Location
Arrival
Time
Water
(Y/N)
BND
UNB
UNK
Total Post
Fledglings
Broods/
Ducklings
(stage if
known)
*HY
Banded
HY
Unbanded
Flew in/
Flew
out/
Flew by
/
Radar Hill Seeps
/
Ball Field Big
Ball Field Little
Fuel Farm
Brackish Pond
Brackish Pond
Adjacent Wetland
Brackish Pond
Forest Depression
(overflow)
Sunrise Seep
Communications
Seep
Parade Seep
Tarmac Pool
R2 Treatment
Pools
R2 Wetland
Catchment Basin
Mauka-Makai
Drainage Ditch
Mauka-Makai
Ironwood Seep
Aviary Seep
Rusty Bucket
Seep
Other (describe)
or give GPS
Coordinate
Totals
*HY may not be distinguishable in the field by plumage after September. May-Aug most unbanded birds can be aged as HY or AHY
by eye ring and plumage. All temp banded birds are likely to by ASY. Example of Clockwise wetlands route:
Catchment, Mauka-Makai, Aviary, Ironwood, Rusty Bucket, Radar Hills, Ball Fields, Fuel Farm,
Brackish Pond & adjacent wetlands, Sunrise, Communications, Parade, R2.
Incidental Resights/ Observations:
August 2010
49
Notes
50
EASTERN ISLAND LADU Standard Resight Survey of All Wetlands (2 hours)
Date:
Observers:
Time start:
Time end:
Sunrise/Sunset: _____/_____
Rain:
_(0-4)
Wind:
__ (Beaufort Scale)
Clouds:
%
Starting Point #______
Start Location:________________
Direction:_______________
Post
Fledglings
Male
□
Opportunistic One Island Survey □
Unidentified
Sex, Post
Fledglings
Female
Total
Post
Fledglings
Hatch Years
(HY)
Ducklings
Banded
Unbanded
Total:
Unknown
Broods:
TOTALS
TEMPORARY bands—# of unique:_____ # of not unique:_____
Total: _______
Total # not unique ALUMINUM ONLY: ________
Total # of banded DOUBLE COUNTS—at multiple sites: ______ Atoll Wide (for simul. surveys): _____
Total # of UNIQUE BANDS during Resight Survey (check reference list, correct for dbl counts): _____
Location
MONUMENT SEEP
SUNSET SEEP
TOTALS
ROLANDO SEEP
Arrival Time
Depth
Total Ducks
# LADU flew In /
flew out / flew by
Bnd
Bnd
Bnd
Banded
Unb
Unb
Unb
Unbanded
Unk
Unk
Unk
Unknown
TOTAL
TOTAL
TOTAL
TOTAL
/
/
/
/
/
/
/
/
Migrant Waterfowl
Location
RLeg
LLeg
Band No.
Sex
Age
Paired?
Y/N/U
Mate ID
Notes
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
August 2010
50
51
Midway LADU Eastern Island All-Wetlands Count (1 hour 15 minutes)
This count will be discontinued in 2010.
Date: _______ Observers:
Time start: ______ Time end: _____Sunrise/Sunset:
______/______
Rain:
(0-4) Wind:
(Beaufort Scale) Cloud Cover:
%
Start location: ____________ End Location: _____________ Direction: ________
□
Opportunistic Survey □
Total number of birds observed with temporary bands:
Eastern
Island
Location
Arrival
Time
Water
(Y/N)
BND
UNB
UNK
Broods/
Ducklings
(stage if
known)
Total
Post
Fledge
LADU
*HY
Banded
Notes
HY
Unbanded
Monument
Seep
Rolando Seep
Sunset Seep
Other
Totals
*HY may not be distinguishable in the field by plumage after September. May-Aug most unbanded birds can be aged as HY or AHY
by eye ring and plumage. All temp banded birds are likely to by ASY. Start locations same as for Eastern Resight survey.
Incidental resights at last site if time allows:
August 2010
51
52
ATTACHMENT 2. MIDWAY ATOLL LAYSAN TEAL SURVEY START LOCATIONS AND
DIRECTION OF TRAVEL TABLES
Eight starting points and directions for Sand Island Standard Resight Surveys of All
Wetlands (use in the following order, then restart):
Starting point
Direction
1
Catchment
Clockwise
2
Brackish Pond
Counter
3
Catchment
Counter
4
Rusty Bucket
Counter
5
Fuel Farm
Clockwise
6
Ball field
Counter
7
Brackish Pond
Clockwise
8
Rusty Bucket
Clockwise
Date
Date
Example of clockwise wetlands: Catchment, Mauka-Makai, Ironwood, Aviary, Rusty
Bucket, Radar Hills, Ball Fields, Fuel Farm, Brackish Pond, Sunrise, Communications,
Parade, R2.
Six starting points and orders for Eastern Island Resight (and All-Wetlands Count)
(use in the following order, then restart):
Finish point
Start point
Middle point
1
Sunset
Monument
Rolando
2
Rolando
Monument
Sunset
3
Monument
Rolando
Sunset
4
Sunset
Rolando
Monument
5
Rolando
Sunset
Monument
6
Monument
Sunset
Rolando
August 2010
Resight
Survey
Date
Wetland
Count
Date
52
Attachment 3. Maps illustrating survey routes on Sand Island & Eastern Island. Original Pilot Study: Sand Island Laysan Teal Standard Resight Survey Route
Ballfield Little
Ballfield big
Radar Hill 1
Radar Hill 2
Brackish Pond
Sunrise
Mauka-Makai
Catchment
53
Attachment 3. Sand Island Laysan Duck All-Wetlands Count Route/Revised All-Wetlands Resight Route
Fuel Farm
Ball field Little
Ball field Big
Rusty Bucket
Radar Hill 1
Radar Hill 2
Tarmac Pool (if water)
Brackish
Forest Dep.
Brackish Pond
Parade
Sunrise
Aviary
Mauka-Makai
Ironwood
Dump (if water)
Brackish Adj.
Wetland
Communications
R2 Treatment Pools
Catchment
R2 Wetland
Sand Island New Resight Survey Route
54
Attachment 3. Eastern Island Original Laysan Duck Survey Route
Monument
Rolando
Sunset
55
ATTACHMENT 4. MIDWAY ATOLL LAYSAN TEAL RESIGHT REFERENCE,
MIDWAY_RESIGHT_REFERENCE_20AUG2010.XLS
ORIGIN/REHAB
NOTES – MIA ducks require careful confirmation if
seen (check sex, correct code, legs, read AL band if
possible).
896-37943
2004 Founder
Seen 17-Feb-10
ASY
896-37941
2004 Founder
Seen 25-Jun-10
M
ASY
805-70841
2004 Founder
Seen 02-Jul-10
GN/2WG
M
ASY
805-70851
2004 Founder
MIA; Last seen 11-Mar-08
AL
o-temp
M
ASY
896-37956
2004 Founder
Glued Temp; confirm sex duplicate band on female; Seen
21-Mar-09
9
NONE
AL
M
ASY
896-37958
2004 Founder
Read band; Confirmed; Seen 28-Jun-10
11
BK
AL
M
ASY
805-70850
2004 Founder
Seen 16-Dec-09
12
GY5
AL
M
ASY
805-70856
2004 Founder
MIA; worn color band; Last seen 18-May-07
13
AL
WWE
M
ASY
1056-99915
2004 Founder
Was AL/BF; Seen 04-Aug-10
14
lb-temp
AL
F
ASY
995-16185
2004 Founder
Seen 23-Jun-10
16
Y2
AL
F
ASY
805-70858
2004 Founder
Seen 14-Jul-10
17
OF
AL
F
ASY
805-70837
2004 Founder
Worn color band; Seen 23-Mar-09
19
AL
Y/BKG
M
ASY
805-70861
2004 Founder
Seen 07-Jul-10
21
W$
AL
F
ASY
896-37944
2005 Founder
Seen 11-Jan-10
22
AL
BKY#
F
ASY
896-37942
2005 Founder
Was O* on Eastern; Seen 20-Apr-10
23
AL
Y#
F
ASY
1035-44062
2005 Founder
Seen 17-Feb-10
24
AL
W6
M
ASY
896-37951
2005 Founder
New W6 band given in Oct 09; Seen 09-Mar-10
25
GY+
AL
F
ASY
1056-99809
2005 Founder
Seen 29-Jul-09
26
AL
NONE
(?)
M
ASY
896-37945
2005 Founder
MIA; Lost color band GYK?; Read band; Last seen 23Oct-07
27
BY3
AL
M
ASY
896-37987
2005 Founder
Was BY2; Seen 18-Feb-10
28
B?
AL
M
ASY
1056-99808
2005 Founder
MIA since Jan 08;. Could be confused w/ BY? Identify
legs, sex, age, color of symbol to confirm alive. Read AL
band if possible.
32
YR
AL
M
ASY
856-89490
2005 Founder
Worn color band; Seen 28-Oct-09
36
B-
AL
F
ASY
1035-44033
2005 Founder
Worn color band, white head; Seen 11-Jan-10
37
WT
NONE
F
ASY
NONE
2005 Founder
Seen 28-Jul-10
38
BYA
AL
F
ASY
1035-44022
2005 Founder
MIA; Last seen 29-Nov-08
39
WC
AL
M
ASY
805-70826
2005 Founder
Worn color band; Seen 09-Dec-09
40
WMA
NONE
F
ASY
NONE
2005 Founder
MIA; Was YJ; New band combo Nov 2007; Last seen
08-Nov-07
42
NONE
B$
F
ASY
NONE
2005 Founder
MIA; Last seen 03-Oct-08
44
AL
DB
F
ASY
896-37957
F1 2005
Read AL; Permanently applied temp color band; was
BYE; Seen 08-Jun-10
45
AL
BYF
M
ASY
896-37939
F1 2005
Seen 16-Dec-09
46
AL
BYJ
M
ASY
896-37902
F1 2005
Seen 15-Dec-09
Midway
LINK #
RLEG
LLEG
SEX
2010
AGE
USFWS
1
ON
AL
M
ASY
2
AL
W8
M
3
NONE
AL
7
AL
8
Attachment 4. Midway Atoll Laysan Duck Resight Reference as of 20 August 2010
ORIGIN/REHAB
possible).
896-37905
F1 2005
Seen 23-Jun-10
ASY
1035-94103
F1 2005
F
ASY
NONE
F1 2005
Seen 18-Feb-10
BKY7
F
ASY
896-37950
F1 2005
Was BR7; Seen 13-Jul-10
AL
GYC
M
ASY
1035-94106
F1 2006
Color band upside down; Seen 14-Jul-10
59
GYE
AL
F
ASY
1035-94107
F1 2006
60
AL
BR/2WG
F
ASY
1035-94109
F1 2006
Seen 10-Feb-10
62
GN1
NONE
M
ASY
NONE
F1 2006
Seen 11-Aug-10
63
AL
R*
F
ASY
896-37986
F1 2006
Seen 15-Jul-10
64
AL
BR+
F
ASY
1035-94113
F1 2006
Seen 04-Feb-10
65
AL
W
M
ASY
1035-94114
F1 2006
66
AL
NONE
F
ASY
1035-94115
F1 2006
MIA; Need to read band; Last seen 29-Oct-09
68
AL
OE
F
ASY
1035-94117
F1 2006
69
AL
r-temp
M
ASY
1035-94118
F1 2006
Maybe on right leg? Seen 05-Oct-09
70
AL
OK
F
ASY
1035-94119
F1 2006
Seen 11-Mar-08
71
AL
OM
F
ASY
896-37959
F1 2006
Seen 23-Mar-09
72
AL
OP
U
ASY
1035-94121
F1 2006
73
YA
AL
F
ASY
1035-94122
F1 2006
YA also on female LL; Seen 09-Nov-09
74
NONE
B1
F
ASY
NONE
F1 2006
Seen 10-Feb-10
75
AL
YC
U
ASY
1035-94124
F1 2006
Seen 01-Jul-10
76
AL
GNA
F
ASY
1035-94125
F2 2006
May look like a GN4; Seen 01-Apr-10
77
GNC
AL
M
ASY
896-37906
F2 2006
AL read Nov. 9, 2009; Seen 15-Jul-10
79
GNE
AL
F
ASY
896-37908
F1 2006
MIA; Worn band; Last seen 15-Apr-08
80
GNF
AL
F
ASY
896-37909
F1 2006
Seen 05-Jul-10
81
GNH
AL
F
ASY
896-37910
F1 2006
Lots of white on head; Faded band; Seen 11-Jan-10
82
AL
YE
F
ASY
896-37911
F1 2006
Seen 14-Jul-10
83
AL
BY+
M
ASY
896-37912
F1 2006
White head; Seen 11-Jan-10
84
AL
BY$
M
ASY
896-37913
F1 2006
Color band worn; Seen 16-Nov-09
86
AL
BY&
M
ASY
896-37915
F1 2006
Seen 28-Jun-10
89
YF
AL
M
ASY
896-37917
F1 2006
Worn band; Seen 11-Jan-10
90
AL
NONE
M
ASY
896-37919
F1-2 2006
Was GN2; Seen 29-Dec-09
91
AL
GNJ
M
ASY
896-37920
Rehab 2008
Held for 48 hrs during Botulism in 2008; F1-2 2006;
Seen 08-Dec-09
92
BRX
AL
M
ASY
896-37921
F1-2 2006
Seen 26-Jul-10
93
BRK
AL
F
ASY
896-37922
F1 2006
Seen 14-Mar-09
94
NONE
AL
F
ASY
896-37923
F1 2006
MIA; Read band; Broken thumb feather; Last seen 12Nov-08
95
O>
AL
M
ASY
896-37924
F1-2 2006
White head; Seen 23-Jun-10
Midway
LINK #
RLEG
LLEG
SEX
2010
AGE
USFWS
51
Y4
AL
M
ASY
52
YW
AL
M
53
NONE
Y0
54
AL
57
57
ORIGIN/REHAB
possible).
896-37927
F1-2 2006
Very white head; Band worn; Seen 23-Jun-10
ASY
896-37928
F1-2 2006
MIA; Could be confused with BY6; Last seen 21-Mar-08
F
ASY
896-37929
F1-2 2006
Seen 06-Nov-09
AL
M
ASY
896-37930
F1-2 2006
MIA; Last seen 03-Sep-08
GNT
AL
M
ASY
896-37932
F1-2 2006
Bill tan at tip; Seen 01-Apr-10
105
AL
YK
M
ASY
896-37934
F1 2006
Worn band; Seen 26-May-10
107
AL
YP
F
ASY
896-37936
F1 2006
Seen 14-Jul-10
109
AL
YX
M
ASY
896-37938
F1 2006
Band worn; Seen 30-Jun-10
110
AL
YU
F
ASY
896-37940
F1 2006
Seen 14-Jul-10
111
AL
BYM
M
ASY
896-37946
F1 2006
Seen 17-Jan-09
112
AL
BYP
F
ASY
896-37947
F1 2006
Seen 23-Jun-10
113
YY
AL
F
ASY
896-37948
F1 2006
114
AL
GN3
M
ASY
896-37949
F2 2006
Seen 16-Jul-10
122
AL
GNX$
F
ASY
1056-99939
F1-2 2007
Glued temps-high band loss; Seen 28-Apr-09
126
AL
WWP
F
ASY
896-37953
F1-2 2007
Seen 07-Jul-10
127
AL
WWK
F
ASY
896-37954
F1-2 2007
Seen 29-Jun-10
128
AL
WWT
F
ASY
896-37955
F1-2 2007
Seen 02-Jul-10
129
GYT
AL
M
ASY
1036-14852
F1-2 2007
Seen 30-Jun-10
130
GNXU
AL
M
ASY
1056-99978
F1-2 2007
Seen 23-May-09
132
AL
WMXJ
F
ASY
1036-14838
F1-2 2007
Was y-temp/dgn-temp; Seen 18-Feb-09
137
AL
WW4
M
ASY
1056-99926
F1-2 2007
Was w-temp/y-temp; Seen 13-Jul-10
139
GNX-
AL
F
ASY
1056-99936
F1-2 2007
Was hp-temp/hp-temp; Seen 01-Dec-09
140
YC8
AL
M
ASY
1056-99941
F1-2 2007
Was y-temp/lgn-temp, then just y-temp; Seen 23-Jun-10
149
AL
GY\
F
ASY
1036-14811
Rehab 2008
F1-2 2007; Seen 05-Oct-09
150
AL
WMK
M
ASY
896-37591
F1-2 2007
New bands, replaced hp-temp, 0-temp; Seen 08-Oct-09
154
GN?
AL
F
ASY
1036-14849
F1-2 2007
Was w-temp/hp-temp; Seen 27-Jul-09
157
RJ
AL
F
ASY
896-37962
F1-2 2007
Seen 03-Jul-10
158
R0
AL
F
ASY
896-37963
F1-2 2007
Seen 21-Jul-10
160
AL
RR
M
ASY
896-37965
F1-2 2007
Seen 14-Jul-10
161
AL
R8
F
ASY
896-37966
F1-2 2007
Seen 21-Jan-10
162
AL
R6
F
ASY
896-37967
F1-2 2007
Seen 04-Aug-10
163
R/WG
AL
M
ASY
896-37968
F1-2 2007
Seen 23-Feb-10
164
AL
R2
M
ASY
896-37969
F1-2 2007
Seen 15-Jun-10
165
GYU
AL
F
ASY
896-37970
F1-2 2007
166
AL
RH
F
ASY
896-37971
F1-2 2007
Confirm right leg and left leg; Possible recording error;
Seen 10-Aug-10
167
AL
RN
F?
ASY
896-37972
F1-2 2007
MIA; Last seen15-Dec-08
Midway
LINK #
RLEG
LLEG
SEX
2010
AGE
USFWS
98
B5
AL
F
ASY
99
B6
AL
F
100
B7
AL
101
B9
103
58
ORIGIN/REHAB
possible).
896-37973
F1-2 2007
Seen 04-Feb-10
ASY
896-37975
F1-2 2007
Seen 22-Jul-10
M
ASY
896-37976
F1-2 2007
Seen 11-Jan-10
AL
M
ASY
896-37977
F1-2 2007
MIA; Last seen 15-Dec-08
R+
AL
F
ASY
896-37978
F1-2 2007
Seen 21-Jul-10
174
RP
AL
M
ASY
896-37979
F1-2 2007
Seen 14-Mar-09
175
RX
RW
M
ASY
NONE
F1-2 2007
RW upside down? Seen 04-Aug-10
176
R3
AL
F
ASY
896-37980
F1-2 2007
Seen 04-Aug-10
177
AL
RY
F
ASY
896-37981
F1-2 2007
Seen 04-Feb-09
178
RA
AL
F
ASY
896-37982
F1-2 2007
Seen 11-Jan-10
184
WW1
AL
M
ASY
1056-99917
F1-2 2007
Seen 28-Oct-09
186
BY?
AL
M
ASY
1056-99948
F1-2 2007
Was dgn-temp/none; Seen 01-Jul-10; Confirm could be
confused with B?
190
AL
WM5
M
ASY
1056-99969
F1-2 2007
Removed GNXP very worn; Seen 07-Jul-10
192
AL
OX0
F
ASY
1036-14827
F1-2 2007
Seen 04-Aug-10
194
BRE
AL
F
ASY
1056-99963
F1-2 2007
Glued temps-high band loss; Seen 08-Jan-10
196
AL
YX9
M
ASY
1056-99935
F1-2 2007
Seen 27-Mar-10
198
AL
YC9
F
ASY
1056-99992
F1-2 2007
Replaced temp O on LL; None RL; Seen 07-Jul-10
200
AL
R>
M
ASY
896-37982
F1-2 2007
Seen 12-Jul-10
201
R5
AL
F
ASY
896-37983
F1-2 2007
Seen 14-Jul-10
203
AL
BK/2YG
F
ASY
896-37989
F1-2 2007
Seen 25-Jul-10
205
AL
BKY+
F
ASY
896-37991
F1-2 2007
Seen 23-Dec-09
206
BKYA
AL
F
ASY
896-37992
F1-2 2007
Seen 17-Feb-10
207
AL
W/2MG
F
ASY
896-37993
F1-2 2007
Seen 30-Mar-10
208
WM#
AL
M
ASY
896-37994
F1-2 2007
Check legs! Same color band on opposite leg of different
bird; Seen 11-Jan-10
209
AL
BKY>
F
ASY
896-37995
F1-2 2007
211
AL
BKY1
F
ASY
896-37996
F1-2 2007
Seen 22-Apr-10
212
WM>
AL
U
ASY
896-37997
F1-2 2007
Seen 20-Apr-10
213
WMJ
AL
M
ASY
896-37998
F1-2 2007
Seen 13-Jul-10
214
WM*
AL
F
ASY
896-37999
F1-2 2007
Seen 14-Jul-10
215
WM/
AL
M
ASY
896-38000
F1-2 2007
Seen 12-Jul-10
217
AL
WM-
M
ASY
1056-99851
F1-2 2007
Seen 11-Aug-10
218
AL
BKYM
M
ASY
1056-99849
F1-2 2007
Seen 29-Dec-09
220
AL
WMM
M
ASY
1056-99852
F1-2 2007
Seen 04-Feb-09
221
BKYT
AL
M
ASY
1056-99853
F1-2 2007
Faded band; Seen 14-Jul-10
222
BKY-
AL
F
ASY
1056-99855
F1-2 2007
Faded band; Seen 23-Jul-10
223
AL
WM0
M
ASY
1056-99857
F1-2 2007
Seen 15-Dec-09
Midway
LINK #
RLEG
LLEG
SEX
2010
AGE
USFWS
168
AL
RU
F
ASY
170
AL
R#
M
171
AL
R$
172
GYN
173
59
ORIGIN/REHAB
NOTES – MIA birds require careful confirmation if
possible).
NONE
F1-2 2007
No band on LL; Worn band; Seen 09-Jul-10
ASY
1056-99856
F1-2 2007
M
ASY
NONE
F1-2 2007
Seen 23-Feb-10
BKY*
F
ASY
1035-94130
F1-2 2007
5 aluminum, worn band; Seen 08-Jan-10
AL
WMU
F?
ASY
1056-99858
F1-2 2007
230
AL
WM#
M?
ASY
1056-99859
F1-2 2007
Seen 14-Jul-10
231
BKY3
AL
F
ASY
1056-99860
F1-2 2007
Some wear; Seen 09-Jul-10
233
BKY8
NONE
F
ASY
NONE
F1-2 2007
Seen 06-Jan-10
235
AL
BKYR
F
ASY
976-20001
Rehab 2008
F1-3; Seen 28-Jul-10
236
AL
BKYX
U
ASY
967-20006
Rehab 2008
F1-3 2008; Seen 04-Aug-10
238
AL
WM7
F
ASY
967-20002
Rehab 2008
F1-3 2008; Seen 17-Feb-10
239
BKY/
AL
F
ASY
967-20003
Rehab 2008
F1-2 2007; Seen 05-Jul-10
240
AL
R4
F
ASY
967-20004
Rehab 2008
F1-3 2008; Seen 28-Jul-10
241
AL
WMN
F
ASY
967-20010
Rehab 2008
F1-3 2008; Faded badly; Seen 14-Jul-10
243
BKY$
AL
U
ASY
1036-14802
Rehab 2008
F1-3 2008; Seen 03-Sep-09
244
AL
BKYY
M
ASY
1036-14801
Rehab 2008
F1-3 2008; Squinty eye; Seen 28-Sep-09
245
BKY6
AL
U
ASY
1036-14803
Rehab 2008
F1-3 2008; Seen 05-Oct-09
246
BKY?
AL
F
ASY
1036-14804
Rehab 2008
F1-2 2007; Seen 25-Jun-10
248
BKY+
AL
M
ASY
1036-14806
Rehab 2008 and
2009
F1-3 2008; Seen 11-Aug-10
Midway
LINK #
RLEG
LLEG
SEX
2010
AGE
USFWS
224
BKYH
NONE
M
ASY
225
AL
BKY0
F?
226
WMH
NONE
227
AL
228
249
BK/2YG
AL
M
ASY
1036-14807
Rehab 2008
Duplicate combo on opposite leg; F1-2 2007; Seen 11Aug-10
251
R/2WG
AL
F
ASY
1036-14809
Rehab 2008
Only resighted once in field; F1-2 2007; Seen 14-Sep-09
252
AL
GY1
F
ASY
1036-14810
Rehab 2008
Upside down color band; F1-2 2007; Seen 12-Jul-10
254
WM1
AL
M
ASY
1036-14812
Rehab 2008
F1-3 2008; Seen 08-Jun-10
255
GY4
AL
M
ASY
1036-14813
Rehab 2008
255
GYA
AL
M
ASY
1036-14813
Rehab 2008
256
RT
AL
M
ASY
1036-14814
Rehab 2008
F1-3 2008; Seen 13-Jul-10
257
AL
WY
F
ASY
896-37593
Rehab 2008
F1-3 2008; Replaced lb-temp/None with permanent
bands; Seen 14-Jul-10
258
LGN
AL
F
ASY
1036-14815
Rehab 2008
Glued temp; F1-2 2007; Seen 05-May-10
259
FU
AL
M
ASY
1036-14816
Rehab 2008
F1-3 2008; Seen 08-Jan-10
260
Y
AL
M
ASY
1036-14818
Rehab 2008
F1-3 2008; Seen 10-Aug-10
261
OR
AL
M
ASY
1036-14819
Rehab 2008
Replaced unglued o-temp with OR; F1-3 2008; Seen 10Aug-10
262
R
AL
F
ASY
1036-14820
Rehab 2008
F1-3 2008; Glued temp; Seen 30-Mar-10
263
DGN
AL
M
ASY
1036-14821
Rehab 2008
F1-3 2008; Glued temp; Cloudy left eye; Seen 29-Dec-09
264
AL
FU
F
ASY
1036-14822
Rehab 2008
Glued temp; F1-2 2007; Seen 17-Nov-09
265
AL
O
F
ASY
1036-14823
F1-2 2007
Confirm sex; Duplicate band on ASY M; Seen 14-Jul-10
F1-3 2008; Needs band confirmation, possible data error;
Band could be GYA; Need to check and read AL; Seen
22-Jan-10
F1-3 2008; Band could be GY4; Need to check and read
AL; Seen 25-Jun-10
60
ORIGIN/REHAB
possible).
1056-99877
F1-3 2008
Seen 16-Jul-10
ASY
1036-14828
F1-3 2008
Seen 27-Jan-10
M?
ASY
1056-99878
F1-3 2008
Seen 10-Jul-10
AL
M
ASY
1056-99879
F1-2 2007
Seen with marine debris March 2009; Seen 14-Jul-10
GNX2
AL
M
ASY
1056-99881
F1-3 2008
Seen 14-Jul-10
273
AL
WMX0
M
ASY
1056-99882
F1-3 2008
Seen 09-Aug-10
274
AL
OX3
M
ASY
1056-99883
F1-3 2008
Seen 07-Jul-10
275
OX4
AL
M
ASY
1056-99884
F1-2 2007
Seen 03-Jun-09
276
GNX3
AL
M
ASY
1056-99885
F1-2 2007
Seen 22-Jul-10
278
GYY
AL
F
ASY
1056-99887
Rehab 2009
Mistakenly reported as carcass; F1-2 2007; Seen 08-Aug10
279
AL
GY2
M
ASY
1056-99888
F1-2 2007
Seen 14-Jul-10
280
GY-
AL
F
ASY
1056-99889
F1-2 2007
Seen 11-Aug-10
281
AL
GY3
F
ASY
1056-99890
F1-2 2007
Confirm this bird; worn color band looks white?; Seen
18-Feb-10
282
AL
WMX1
F
ASY
1056-99891
F1-3 2008
Seen 07-Aug-10
283
AL
WMX2
M
ASY
1056-99892
F1-2 2007
Seen 11-Aug-10
284
AL
GY6
M
ASY
1056-99893
F1-2 2007
Seen 14-Jul-10
286
AL
OX5
F
ASY
1056-99895
F1-2 2007
Seen 29-Aug-09
289
GY/BKG
AL
M
ASY
1056-99898
F1-2 2007
Seen 23-Jun-10
290
GNX5
AL
F
ASY
1056-99899
F1-2 2007
Seen 03-Jul-10
291
AL
WMXA
M
ASY
1036-14832
F1-2 2007
Seen 07-Jul-10
296
AL
WMXC
M
ASY
1036-14833
F1-3 2008
Limp; Seen 23-Jun-10
297
GNX8
AL
F
ASY
1036-14834
F1-2 2007
Seen 30-Jun-10
299
AL
WMXE
M
ASY
1036-14835
F1-3 2008
Seen 14-Jul-10
300
WMXH
AL
F
ASY
1105-11703
F1-3 2008
New AL band on 03-Oct-09; Seen 12-Dec-09
302
WMXK
AL
M
ASY
1036-14840
F1-3 2008
Seen 21-Apr-09
303
NONE
O1
F
ASY
NONE
F1-2 2007
Seen 24-Oct-09
304
WMXN
AL
F
ASY
1036-14842
F1-3 2008
Seen 15-Jul-10
305
WMXP
AL
M
ASY
1036-14843
F1-2 2007
Seen 10-Aug-10
306
OU
o-temp
F
ASY
NONE
F1-3 2008
Seen 29-Jun-10
307
AL
GNN
M
ASY
1036-14886
F1-2 2007
Seen 11-Jan-10
308
AL
O$
F
ASY
1036-14887
F1-3 2008
Seen 01-Jun-10
309
GN>
db-temp
M?
ASY
NONE
F1-3 2008
MIA; Glued Temp; Last seen 26-Nov-08
310
GN+
AL
F
ASY
1036-14865
F1-3 2008
Seen 25-Jul-10
311
OX9
AL
M
ASY
1036-14866
F1-2 2007
Seen 09-May-10
312
GN*
AL
F
ASY
1036-14867
F1-2 2007
Seen 12-Mar-09
Midway
LINK #
RLEG
LLEG
SEX
2010
AGE
USFWS
267
AL
WMX-
F
ASY
268
GNX0
AL
F
269
OX1
AL
270
OX2
272
61
ORIGIN/REHAB
possible).
1036-14868
F1-2 2007
Seen 24-Oct-09
ASY
1036-14869
F1-2 2007
Seen 14-Jul-10
M
ASY
1036-14870
F1-2 2007
Seen 14-Jul-10
WMX+
F
ASY
1036-14871
F1-2 2007
Seen 25-Feb-09
AL
O#
M
ASY
1036-14872
F1-2 2007
Band worn; Seen 30-Jun-10
318
OX
AL
M
ASY
1036-14873
F1-3 2008
Lots of white on head; Seen 25-Mar-10
320
AL
WM3
F
ASY
1056-99859
F1-2 2007
Seen 18-Feb-10
321
AL
WWX
M
ASY
1056-99900
F1-2 2007
Check for limp; Seen 05-Jul-10
322
AL
GNXA
F
ASY
1056-99901
F1-2 2007
Worn color band; Seen 23-Jun-10
323
AL
BY2
F
ASY
1056-99902
F1-3 2008
Seen 14-Jul-10
324
AL
WW+
F
ASY
1036-14854
F1-2 2007
Last seen 28-Jul-10
325
GN/WG
AL
M
ASY
1036-14844
F1-3 2007/2008
Seen 11-Jan-10
326
AL
GNXC
M
ASY
1036-14850
F1-3 2008
Seen 02-Dec-09
327
AL
GN$
F
ASY
1036-14855
F1-2 2007
Seen 06-Jan-10
328
WMXU
AL
F
ASY
1105-11701
F1-3 2008
Seen 02-Apr-09
329
AL
R?
F
ASY
1036-14856
F1-3 2008
Confirm sex of bird; Duplicate combo on male; Seen 17Mar-10
330
AL
WMX4
F
ASY
1036-14857
F1-2 2007
Seen 09-Mar-10
331
YC1
AL
M
ASY
1036-14845
F1-3 2007/2008
Seen 13-Jul-10
332
GY?
AL
M
ASY
1036-14846
F1-3 2007/2008
Seen 08-Jun-10
333
AL
R-
F
ASY
1036-14858
F1-3 2007/2008
Seen 30-Mar-10
334
AL
YC4
M
ASY
1036-14859
F1-2 2007
Seen 28-Jul-10
335
WMX5
NONE
F
ASY
NONE
F1-2 2007
Seen 11-Jan-10
336
AL
OT
F
ASY
1036-14860
F1-3 2008
Confirmed sex is F; Some green in bill; Seen 15-Jun-10
337
AL
YC5
M
ASY
1036-14861
F1-2 2007
Seen 07-Jul-10
339
AL
O-
M
ASY
1036-14862
F1-3 2007/2008
Seen 11-Aug-10
340
AL
BRT
F
ASY
1036-14847
F1-3 2007/2008
Seen 14-Jul-10
341
AL
WMXY
M
ASY
1036-14848
F1-2 2007
Seen 07-Jul-10
342
AL
WMXT
F
ASY
1036-14853
F1-3 2007/2008
Seen 08-Sep-09
343
WMXR
AL
M
ASY
1056-99903
F1-3 2007/2008
Seen 05-Jan-10
345
GYH
AL
M
ASY
1056-99905
F1-3 2007/2008
Seen 16-Jul-10
346
WW-
AL
M
ASY
1056-99906
F1-3 2007/2008
Seen 07-Jul-10
347
WW>
AL
M
ASY
1056-99907
F1-3 2007/2008
Seen 10-Aug-10
348
AL
WW7
M
ASY
1056-99908
F1-3 2007/2008
Seen 14-Jul-10
349
AL
WWY
M
ASY
1056-99909
F1-3 2007/2008
Seen 07-Aug-10
350
AL
BR$
F
ASY
1056-99910
F1-3 2007/2008
Added BR$ on 29-Oct-09; Prior to this only AL; Seen
11-Jan-10
351
AL
YXP
F
ASY
1056-99911
F1-3 2007/2008
Seen 29-Jun-10
Midway
LINK #
RLEG
LLEG
SEX
2010
AGE
USFWS
313
WM4
AL
F
ASY
314
O?
AL
M
315
AL
GNR
316
AL
317
62
ORIGIN/REHAB
possible).
1056-99912
F1-3 2007/2008
Seen 22-May-09
ASY
1056-99913
F1-3 2007/2008
Seen 16-Apr-10
M
ASY
1056-99914
F1-3 2007/2008
Seen 24-Nov-09
WW2
M
ASY
1056-99918
F1-3 2007/2008
Seen 26-Jul-10
YX1
AL
M
ASY
1056-99919
F1-3 2007/2008
Seen 11-Aug-10
357
GNX>
AL
F
ASY
1056-99920
F1-3 2007/2008
Seen 29-Dec-09
358
AL
YX2
M
ASY
1056-99921
F1-3 2007/2008
This duck is blind; Seen 09-Dec-09
359
YX3
AL
M
ASY
1056-99922
F1-3 2007/2008
Confirm band combination; Legs may be reversed; Seen
01-Jun-10
360
AL
YX4
M
ASY
1056-99923
F1-3 2007/2008
Seen 30-Jun-10
361
YX5
AL
M
ASY
1056-99924
F1-3 2007/2008
Seen 07-Mar-10
362
WW3
AL
M
ASY
1056-99925
F1-3 2007/2008
Seen 14-Jul-10
363
WW6
AL
M
ASY
1056-99927
F1-3 2007/2008
Seen 08-Jul-10
364
AL
WW8
M
ASY
1056-99928
F1-3 2007/2008
Seen 07-Jul-10
365
WW9
AL
M
ASY
1056-99929
F1-3 2007/2008
Seen 14-Jul-10
366
AL
GNX>
F
ASY
1105-11702
F1-3 2007/2008
Seen 06-May-09
367
GNX?
AL
F
ASY
1056-99930
F1-3 2007/2008
Badly faded; Seen 20-Apr-10
368
YX6
AL
M
ASY
1056-99931
F1-3 2007/2008
Seen 23-Feb-10
369
AL
GNX+
F
ASY
1056-99932
F1-3 2007/2008
Seen 01-Jul-10
371
YX8
AL
M
ASY
1056-99934
F1-3 2007/2008
Seen 07-Jul-10
372
AL
WWJ
M
ASY
1056-99937
F1-3 2007/2008
Seen 22-Apr-10
373
YX>
AL
F
ASY
1056-99938
F1-3 2007/2008
Seen 08-Sep-09
374
AL
YC7
M
ASY
1056-99940
F1-3 2007/2008
Seen 28-Apr-09
375
AL
YC0
M
ASY
1056-99942
F1-3 2007/2008
Seen 11-Aug-10
376
AL
YXJ
F
ASY
1056-99943
F1-3 2007/2008
Seen 11-Jan-10
377
YXR
AL
M
ASY
1056-99944
F1-3 2007/2008
Seen 18-Feb-10
378
BYN
AL
M
ASY
1056-99945
F1-3 2007/2008
Seen 14-Jul-10
379
AL
BRC
F
ASY
1056-99946
F1-3 2007/2008
Seen 12-Sep-09
380
AL
O/2BKG
M
ASY
1056-99947
F1-3 2007/2008
Seen 11-Aug-10
381
AL
YX+
M
ASY
1056-99849
F1-3 2007/2008
Faded band; Seen 17-Mar-10
382
AL
RK
F
ASY
1056-99850
F1-3 2007/2008
Seen 12-Dec-09
383
AL
GNXJ
M
ASY
1056-99851
F1-3 2007/2008
Very faded band; Read AL band; Seen 25-Nov-09; Needs
to be recaptured and band replaced
384
AL
BR-
F
ASY
1056-99852
F1-3 2007/2008
Seen 05-May-09
385
AL
BY-
M
ASY
1056-99853
F1-3 2007/2008
Could be confused with B-; Seen 11-Jul-10
386
BY5
AL
M
ASY
1056-99854
F1-3 2007/2008
Could be confused with B5; Seen 13-Nov-09
387
AL
BY6
M
ASY
1056-99855
F1-3 2007/2008
Confirmed as BY9 put on upside-down; Seen 01-Jul-10
388
OBKG
AL
M
ASY
1056-99856
F1-3 2007/2008
Check bands on correct legs; Seen 14-Jul-10
Midway
LINK #
RLEG
LLEG
SEX
2010
AGE
USFWS
352
AL
WW5
F
ASY
353
YXE
AL
F
354
AL
WWA
355
AL
356
63
ORIGIN/REHAB
possible).
1056-99857
F1-3 2007/2008
Seen 18-Feb-10
ASY
1056-99858
F1-3 2007/2008
Seen 11-Aug-10
F
ASY
1056-99859
F1-3 2007/2008
Seen 11-Jan-10
AL
F
ASY
1056-99861
F1-3 2007/2008
Seen 08-Jan-10
AL
BRR
F
ASY
1056-99862
F1-3 2007/2008
Seen 14-Jul-10
395
BYW
AL
M
ASY
1056-99864
F1-3 2007/2008
Seen 14-Jul-10
396
AL
BRH
F
ASY
1056-99865
F1-3 2007/2008
Seen 10-Feb-10
397
BY7
AL
M
ASY
1056-99866
F1-3 2007/2008
Could be confused with B7; Seen 16-Jul-10
398
AL
BY*
M
ASY
1056-99867
F1-3 2007/2008
Could be confused with B*; Seen 10-Aug-10
399
YX$
AL
M
ASY
1056-99868
F1-3 2007/2008
Seen 04-Aug-10
400
AL
YC6
M
ASY
1056-99870
F1-3 2007/2008
Seen 21-Jul-10
401
WMX#
AL
M
ASY
1056-99971
F1-3 2007/2008
Seen 09-Jul-10
402
AL
GNXH
F
ASY
1056-99972
F1-3 2007/2008
Worn band; Seen 08-Jun-10
403
AL
WWH
M
ASY
1056-99973
F1-3 2007/2008
Seen 11-Jan-10
404
WW0
AL
M
ASY
1056-99974
F1-3 2007/2008
White head; Seen 07-Jul-10
405
GN#
AL
F
ASY
1056-99975
F1-3 2007/2008
Seen 07-Jul-10
406
BRP
AL
F
ASY
1056-99976
F1-3 2007/2008
Seen 23-Jun-10
407
AL
GNXE
M
ASY
1056-99977
F1-3 2007/2008
Very worn band; Seen 07-Jul-10
408
AL
BR>
F
ASY
1056-99979
F1-3 2007/2008
Seen 25-May-09
409
GN
AL
F
ASY
1056-99980
F1-3 2007/2008
Replaced GN5 with GN on 01-Oct-09; Seen 17-Feb-10
410
GNXT
AL
M
ASY
1056-99981
F1-3 2007/2008
Band very faded-mostly white; Seen 08-Jun-10
411
AL
GNXL
U
HY
1056-99982
Rehab 2009
MIA; F1-3 2008; Last seen 16-Jun-09
412
AL
WMX6
M
SY
1056-99983
Rehab 2009
Replaced worn GNXR band with WMX6 on 03-Oct-09;
F1-3 2008; Seen 14-Jul-10
413
AL
GNXM
F
ASY
1056-99984
Rehab 2009
Very faded band; F1-3; Seen 17-Mar-10
415
AL
GNW$
U
HY
1056-99986
Rehab 2009
Band faded, mostly white; May look like WW$; Seen 09May-10
416
AL
GY8
F?
SY
896-37534
F1-3 2007/2008
Seen 29-Sep-09
417
AL
WWC
U
SY
1056-99987
Rehab 2009
MIA; F1-3 2008; Last seen 26-Aug-09
429
WA
AL
M
ASY
1086-89201
Rehab 2009
F1-3 2008; Seen 15-Jun-10
430
AL
GNX
M?
SY
1056-99989
Rehab 2009
F1-4 2009; Confirm sex; Seen 04-Aug-10
431
AL
GNU
M
SY
1056-99990
Rehab 2009
F1-4 2009; Seen 14-Jul-10
432
AL
GN1
M
SY
1056-99991
Rehab 2009
F1-4 2009; Seen 10-Aug-10
434
AL
BYE
M
ASY
1056-99993
F1-3 2007/2008
435
AL
BX
U
SY
1056-99994
F1-4 2009
436
AL
BP
U
SY
1056-99995
F1-4 2009
Could be confused with BYP; Seen 07-Jul-10
437
AL
BA
F
SY
1056-99996
F1-4 2009
Could be confused with BYA; Seen 21-Jul-10
438
AL
BM
F
SY
1056-99997
F1-4 2009
Could be confused with BYM; Seen 08-Sep-09
Midway
LINK #
RLEG
LLEG
SEX
2010
AGE
USFWS
389
AL
BRA
F
ASY
390
YX-
AL
M
391
AL
BRJ
393
BRN
394
Could be confused with BE; Band worn; Seen 11- Aug10
Need to confirm sex of this bird; Could be confused with
BYX; Seen 17-Mar-10
64
ORIGIN/REHAB
possible).
1056-99998
F1-4 2009
Could be confused with BYC; Seen 20-Apr-10
SY
1056-99999
F1-4 2009
Could be confused with BYE; Seen 21-Jul-10
M
SY
1056-00000
F1-4 2009
Could be confused with BYF; Seen 04-Jul-10
BH
U
SY
896-37501
F1-4 2009
Could be confused with BYH; Seen 23-Jun-10
AL
BJ
F
SY
896-37502
F1-4 2009
Seen 08-Jun-10
444
AL
BR
M
ASY
896-37503
F1-3
This is a blue band with a white R; Seen 12-Dec-09
445
AL
BR
F
SY
896-37504
F1-4 2009
446
AL
BT
U
HY
896-37505
F1-4 2009
447
AL
R?
M
SY
896-37506
F1-4 2009
Confirm sex; Duplicate combo on female; Seen 07-Jul-10
448
AL
BW
F
SY
896-37507
F1-4 2009
Could be confused with BYW; Seen 14-Jul-10
449
AL
BY
M
SY
896-37508
F1-4 2009
Could be confused with BYY; Seen 23-Jul-10
450
AL
B2
F
ASY
896-37509
F1-3 2008
Could be confused with BY2; Seen 30-Mar-10
451
AL
B3
M
SY
896-37510
F1-4 2009
Could be confused with BY3; Seen 11-Aug-10
452
AL
B4
M
ASY
896-37511
F1-3 2008
Could be confused with BY4; Seen 30-Dec-09
453
AL
B8
M
SY
896-37512
F1-4 2009
Could be confused with BY8; Seen 10-Aug-10
454
AL
B0
U
SY
896-37513
F1-4 2009
Could be confused with BY0; Seen 07-Jul-10
455
AL
0*
M
SY
896-37514
F1-4 2009
Recycled combo; Missing right tip of bill; Seen 14-Jul-10
456
AL
OA
F
ASY
896-37515
F1-3
Seen 11-Jan-10
457
AL
OC
F
ASY
896-37516
F1-3 2008
Seen 04-Aug-10
458
AL
OJ
F?
SY
896-37517
F1-4 2009
Confirm sex; Seen 20-Apr-10
459
AL
OY
F
ASY
896-37518
F1-3
Seen 21-Jul-10
460
AL
O2
M
SY
896-37519
F1-4 2009
Seen 30-Jun-10
461
AL
O3
F?
SY
896-37520
F1-4 2009
Seen 09-Jul-10
462
AL
O5
F
SY
896-37521
F1-4 2009
Seen 12-May-10
463
AL
O6
M
SY
896-37522
F1-4 2009
Seen 14-Jul-10
464
AL
O7
F
ASY
896-37523
F1-3 2008
Seen 14-Jul-10
465
AL
O8
M
SY
896-37524
F1-4 2009
MIA; Last seen 19-Sep-09
467
AL
GYA
F
SY
896-37526
F1-4 2009
White head; Seen 27-Apr-10
468
AL
GYF
M
SY
896-37527
Rehab 2009
F1-4 2009; Seen 23-Jun-10
469
AL
GYK
M
ASY
896-37528
F1-4
Seen 30-Mar-10
470
AL
GYM
M
ASY
896-37529
F1-4
Seen 28-Sep-09
471
AL
GYR
U
SY
896-37530
F1-4 2009
Seen 21-Sep-09
472
AL
GYW
M
ASY
896-37531
F1-4
Seen 10-Aug-10
473
AL
GY6
M
SY
896-37532
F1-4 2009
Seen 27-Mar-10
474
AL
GY7
F
ASY
896-37533
F1-3
Seen 14-Jul-10
475
GYP
AL
M
ASY
1056-99904
F1-4
Corrected Link #; Seen 16-Apr-10
Midway
LINK #
RLEG
LLEG
SEX
2010
AGE
USFWS
439
AL
BC
F
SY
440
AL
BE
M
441
AL
BF
442
AL
443
This is blue with a white R, not temp brown; Seen 09Nov-09
Confirm sex; Could be confused with BYT; Seen 07-Jul10
65
ORIGIN/REHAB
possible).
1036-14889
F1-3
Seen 22-Jul-10
ASY
1036-14890
Rehab 2009
F1-3; Seen 09-Jul-10
F
SY
896-37544
F1-4 2009
Seen 15-Jun-10
Y>
F
SY
896-37545
F1-4 2009
Seen 07-Jul-10
W?
AL
F
ASY
896-37547
F1-3
Seen 23-Jun-10
483
B
AL
M
SY
896-37549
F1-4 2009
Seen 25-Nov-09
484
W0
AL
F
SY
896-37550
F1-4 2009
Seen 10-Aug-10
485
Y*
AL
F
ASY
896-37551
F1-3 2008
Seen 07-Jul-10
486
GNXY
AL
M
ASY
896-37552
F1-3
Seen 29-Apr-10
487
AL
W-
F
SY
896-37553
F1-4 2009
Seen 21-Jul-10
488
AL
BYC
M
ASY
896-37554
F1-3
Could be confused with BC; Seen 28-Jul-10
489
AL
R/
F
SY
896-37555
F1-4 2009
Seen 08-Jan-10
490
AL
GN8
M
SY
896-37598
F1-4 2009
Seen 05-Jul-10
491
AL
WMX8
F
ASY
896-37599
F1-3
Seen 04-Aug-10
492
BY1
AL
F
SY
1105-11704
F1-4 2009
Could be confused with B1; Seen 24-Jul-10
493
AL
R1
M
ASY
896-37556
F1-3
Seen 14-Jul-10
494
AL
W1
F
ASY
896-37557
F1-3
Seen 11-Aug-10
495
AL
R7
F
ASY
1105-11705
F1-3
Seen 14-Jul-10
496
AL
BY4
M?
SY
896-37558
F1-4 2009
Could be confused with BYA, B4 or BA; Seen 06-Aug10
497
AL
WMX9
F
SY
896-37577
F1-4 2009
Seen 13-Jul-10
498
AL
WMX/
M
ASY
896-37576
F1-3
Seen 01-Oct-09
499
AL
GY0
M
ASY
896-37575
F1-3
Seen 17-Feb-10
500
AL
RE
F
ASY
896-37559
F1-3
Seen 18-Feb-10
501
AL
W2
M
SY
896-37560
F1-4 2009
Seen 25-Jun-10
502
AL
RY
F
SY
896-37562
F1-4 2009
Seen 22-Jul-10
503
AL
W*
F
ASY
896-37561
F1-3
Pukas in webbing; Seen 28-Jul-10
504
AL
WN
F
SY
896-37563
F1-4 2009
Seen 08-Jan-10
505
AL
WK
F?
SY
896-37564
F1-4 2009
Seen 01-Dec-09
506
AL
RM
M
ASY
896-37565
F1-3
Seen 14-Apr-10
507
AL
WJ
F
SY
896-37566
F1-4 2009
Seen 17-Mar-10
508
AL
W7
F
SY
896-37567
F1-4 2009
Seen 14-Jul-10
509
WH
AL
M?
SY
896-37568
F1-4 2009
Seen 11-Aug-10
510
AL
WR
M
SY
896-37569
F1-4 2009
Seen 06-Jan-10
511
AL
WU
F
SY
896-37570
F1-4 2009
Seen 07-Jul-10
512
WMX?
AL
F?
ASY
896-37571
F1-3
Seen 09-Mar-10
513
AL
WMX$
F
SY
896-37573
F1-4 2009
Seen 07-Apr-10
Midway
LINK #
RLEG
LLEG
SEX
2010
AGE
USFWS
476
AL
Y-
F
ASY
477
AL
Y8
F
479
AL
W>
480
AL
482
66
ORIGIN/REHAB
possible).
896-37572
F1-3
Seen 30-Jun-10
ASY
896-37574
F1-3
Seen 20-Apr-10
M
SY
876-37578
F1-4 2009
Seen 10-Jul-10
AL
F
ASY
1105-23801
F1-3
Band upside down (confirm which leg); Seen 13-Jul-10
AL
YN
M
SY
896-37535
F1-4 2009
Band looks like YH; Confirmed as YN; Band worn; Seen
04-Aug-10
520
AL
YA
F
ASY
896-37536
F1-3
Seen 09-Aug-10
521
AL
Y4
M
SY
896-37537
F1-4 2009
Check to make sure not YH; Band worn; Seen 06-Jan-10
522
AL
YJ
U
HY
896-37538
F1-4 2009
Seen 30-Dec-09
523
AL
YM
F
ASY
896-37539
F1-3 2008
Seen 04-Feb-10
524
AL
YT
M
SY
896-37540
F1-4 2009
Seen 23-Jun-10
525
AL
Y1
F
SY
896-37541
F1-4 2009
Seen 04-Feb-10
526
AL
Y3
M
SY
896-37542
F1-4 2009
Seen 17-Nov-09
527
AL
Y5
F
SY
896-37543
F1-4 2009
Seen 14-Jul-10
528
BYG
AL
U
SY
1036-14882
F1-4 2009
AL upside down; Seen 08-Jun-10
529
W3
AL
F
ASY
1036-14892
F1-3 2008
Seen 06-Aug-10
530
AL
OX6
F
ASY
896-37579
Rehab 2009
F1-3 2008; Released at Aviary Oct-09; Seen 22-Jul-10
531
AL
O/BKG
F
SY
896-37580
F1-4 2009
Seen 09-Jul-10
532
AL
O\
F
ASY
896-37581
F1-3 2008
Seen 11-Aug-10
533
AL
YC3
F
SY
896-37582
F1-4 2009
Seen 13-Jul-10
534
AL
YC2
M
SY
896-37583
F1-4 2009
Seen 14-Jul-10
535
AL
GY9
M
ASY
896-37584
F1-3
Seen 27-Mar-10
536
AL
GY0
F
ASY
896-37585
F1-3 2008
Seen 07-Aug-10
537
AL
GY>
M
ASY
896-37586
F1-3 2008
Seen 30-Mar-10
538
AL
BR?
F
SY
1105-11706
F1-4 2009
Seen 05-Oct-09
540
AL
WF
M
ASY
896-37590
F1-3
Big puka on left foot; Seen 13-Jul-10
Midway
LINK #
RLEG
LLEG
SEX
2010
AGE
USFWS
514
WWN
AL
M
ASY
516
WMX>
AL
M
517
RC
AL
518
WMX7
519
67

Population estimates and monitoring of Laysan Teal

Transcription

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