Sky GodS - Eastern Falcon Conservation Trust

Sky Gods
by Donna Falconer
A
tourist bus sweeps past with a
whoosh of air. The occupants are
unlikely to have even noticed the
karearea (NZ falcon) sentinel, silently
perched on a give way sign waiting to
greet them as they drive into the village
at Aoraki Mount Cook. Head bobbing up
and down, she’s more intent anyway on
sizing up her next snack, which will probably be a lizard basking in the sun, oblivious to the danger perched ten metres away
from it, casing the joint.
The karearea has such a sweet innocent
face, almost cherubic and with dark brown
soulful eyes of unfathomable depth. A
vision of pure grace and elegance. A distinctive dark moustache or malar stripe
runs down her cheeks. With her head
cocked to the side, she susses me out,
observing. She is always observing and
completely fearless as I approach to within a metre of her. It’s hard to equate
this innocent looking bird with the high
spec’ killer beneath those unruffled feathers. But high spec’ she sure is. Although
little research has been carried out on
our karearea, much knowledge has been
established for the Peregrine, the most
well known and highly researched of the
falcon species. Peregrine’s have eyesight
estimated to be six to eight times more
powerful than that of a human’s. They fly
at speeds of 230 kmh and can stoop or go
into a hyperdive at speeds of 370 kmh. As
if that isn’t enough, they can pull up to
25 gs coming out of a stoop and can carry
prey six times their own body weight. In
the specialised weaponry department, all
falcons have a notched tomial tooth which
has adapted to sever the spinal cord of
their prey. Charming!
The karearea of the South Island high
country are classified as the eastern falcon, the largest and also the most common of the three New Zealand falcon
subtypes. In the Aoraki Mount Cook area
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adults pair up and courtship commences
in late winter/early spring. Eggs are laid
in a scrape between mid-October and late
November. Scrape sites are chosen under
nicely undercut prominent rock outcrops
which are capable of providing a decent
bivvy. As with all bivvies, some are three
star whilst others are five star. Presumably
scrape selection improves with breeding
experience! New scrape sites are selected
each season, although they may also be
rotated. All will be within a few hundred
meters of each other, i.e. on the same
face of a ridge line or part of a watershed
catchment. Generally scrapes are within
150 metres of water and usually (but not
always) on a north or north-west facing
slope and below 1200m.
It is normally reported that eggs are
laid directly on the ground, however all
scrapes I have observed consisted of loose
but distinctive grass nests in a rock bivvy.
Maybe at higher altitude where there is
no available nesting material, eggs are laid
directly on the ground or rock ledges. From
the time the scrape site is selected and eggs
laid, the area is actively defended against
all intruders. The area of nest defence varies depending on the site and personality
and/or experience of the birds involved.
A particularly enthusiastic pair may start
attacking intruders from 200 – 300 metres
distance. When birds are sitting on eggs
however, they tend to sit tight and will not
give away their location unless you are right
at their outcrop.
Both parents share incubation of the
eggs (~ 30 days), but once hatched, the
female initially cares for the chicks, with the
male supplying all the prey (usually small
birds). The female continues brooding the
chicks until they are independently thermoregulating at 12 days old. By this time
their white natal down has been replaced
by thick grey down. From this time on the
female is helped by the male and both bring
in food and feed the chicks.
Although the chicks are unattended in
the scrape, including at night, one parent
is always perched nearby on guard against
any intrusion into the nesting territory.
The survival rate of chicks is highly
variable, with infertile eggs a significant
contributor to nest failures, along with the
predation of nests in areas where little or
no predator control is undertaken. Feral
cats and mustelids pose the greatest threat
to nesting falcons. Violent spring thunderstorms which rattle around our high
country however may be implicated in the
occurrence of clutches of infertile eggs or
the death of developing embryos. Such
storms, if they occur at a critical period
right after egg laying, may be responsible
for the apparently haphazard occurrence
of localised very poor outcomes in some
breeding seasons.
Chicks double their weight every three
to six days and are fed predominantly on
a diet of small birds and young rabbit or
hare. Chicks take their first flight at around
36 days, with males fledging up to four
days before females. The parents provide
food for the fledglings for up to a couple of
months after fledging. During this time you
may see the parents doing food drops and
mid-air food transfers with the fledglings as
they teach them how to become proficient
independent hunters in often challenging
mountain flying conditions.
Fledglings are cheeky inquisitive birds
with a very high propensity for fun and getting into trouble. Exactly like bored teenagers, they will be heard long before they
are seen as they chase each other around,
bicker and squabble. Although they may
have decamped from their original scrape
bivvy, they will remain in the immediate nest defence area for a month or two.
Young juveniles will often stay together
long after they are independently hunting
and may be seen in their original natal
area a year after fledging. Juvenile females
can successfully breed and raise chicks in
their first year so long as they have a more
experienced partner. For others however,
things often turn to custard and they’ll have
a nest failure. Last season a young female
removed and presumably ate her sole chick,
so predation by the usual suspects can not
be assumed when eggs or chicks go missing
from a scrape.
Adult karearea are distinguished from
juveniles by their yellow soft fleshy parts
(around their eyes, above their beak and
feet) whereas in juveniles these are
white/grey. Overall, juveniles appear darker
in colour as they
lack the distinctive barring on
their
breasts
and
banding
on the back of
their wings and
on their backs.
This more subdued juvenile
plumage aids their ability to
be camouflaged whilst they
are still young inexperienced birds.
Juveniles’ wings are larger than their parents which
compensates for their poorer flight muscles and flying
abilities (they are on training
wings).
Females are significantly larger than
males, one third larger, although to the
untrained eye this can be difficult to ascertain unless both birds are together. Males
have more intensely cinnamon coloured leg
feathers than females.
Attacking karearea are brutal and unforgiving in their nest defence as anyone that
has ventured into a nesting territory will
attest to. Both parents have distinctive
flying styles and work the topography
to their advantage during an attack. The
female is a notorious contour flier who
will erupt over a ridge or crest to meet
you at eye level, regardless of what height
that is. The male on the other hand is
more aerobatic and often comes in from
altitude in a stoop. The male is particularly proficient at hovering to check out
what is going on, particularly if you are at
a scrape site.
When not in attack mode it is a truly
awe-inspiring experience to watch an adult
pair doing aerobatics and really working
the free lift that comes with flying alongside
steep faces and ridge crests. The female is
often positioned as wingman behind the
male during some of their synchronised
manoeuvres. However, if he decides to
put his foot down, he leaves her for dead.
For anyone who has witnessed such aerial
mastery, there is no question that the karearea spend a lot of time purely flying for
fun. It often seems that the more severe the
gale, the more airspeed they can get and
the more fun they have with their aerobatics. Some pairs also have their domestics
during these manoeuvres which makes for
even more entertaining spectating.
Given the attributes of our karearea, for
those of us that love being in our South
Island back country then it’s probably a
very good thing the worlds largest eagle,
our very own Haast’s eagle is no longer
with us. This giant of the raptor world
weighed up to 10 – 15 kilograms, had a 2.6
– 3 metre wingspan, 7.5 centimetre talons
and ate moas for breakfast. Imagine being
attacked by one of them!
In some North American cities the
Department of the Environmental
Protection have a falcon SAR unit, a volunteer falcon watch and rescue
unit that deals with chicks
fledging from high rise
buildings. At least that
is one issue our karearea does not face.
Peregrine’s in the
USA were on the
verge of extinction in the 1960s
as a result of the
use of the pesticide DDT in
agriculture. Here
in New Zealand,
current pest control
regimes are similarly the
greatest threat to our karearea in the high country.
Karearea do eat carrion and
therefore are at the top of
the food chain and are heavily
impacted by many of our current
pest control programmes.
Check out www.nzfalcon.net.nz for more
information and photography of our local
karearea. There is also information on
the website about a conservation trust I
wish to establish for the eastern falcon to
help raise awareness and promote the conservation value of these iconic birds of the
high country.
P h o t o Adult male karearea in attack mode.
Donna Falconer
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