How to make and install an A-frame barn owl nestbox

How to make and install an A-frame
barn owl nestbox
Materials
8x4 sheet of 18mm exterior plywood, preferably from sustainable sources (Scandinavia)*
20.5” x 2x2 softwood (cut to 60º angle) & 18” x 1.5” x 0.5” battens for hatch etc
40 mm screws (and glue by choice)
Woodstain, water-based such as Cuprinol “Ducksback”
Woodchips
*Scraps of ply can be used, but if the thickness is less than 18mm, battens will be needed and the
dimensions will have to be adjusted
Tools
Electric saw, capable of 60º cut
5” hole-saw and/or Jig-saw
Sandpaper
Screwdriver, preferably electric or battery
Paintbrush
Cutting and Assembly
Follow the instructions on Diagrams A, B and C on
subsequent pages.
Installation
- Boxes should generally be installed outside of the bird breeding season (unless an internal or pole box),
ideally between September and February, to avoid the risk of an offence regarding the damage or destruction of birds
nests that are in use. The months of August and March may be acceptable, providing the tree surgeon proceeds with care
checking for late or early nesting birds. Due caution is recommended throughout the year because other bird species, such as
blackbirds and barn owls, have been know to nest throughout the year.
- An inch or two layer of wood chippings or shavings should be sprinkled on the inside of the box floor –
this encourages nesting and stops eggs from rolling around. It often helps to add a few barn owl pellets if
they are available, to give the “lived in feel”.
- The box should be installed 3-5 metres up in the tree, no higher.
- Tree branches should be trimmed so that owls can fly in and out directly.
- The nest box will normally be mounted on a level platform of 2 bearers (2X4” wooden batons), with the
help of a bough or two. The box should be screwed to the bearers and, if possible, to nearby branches so as
to provide a firm and permanent fixing, and avoiding bolts being drilled directly into the trunk. In the
absence of supporting branches 2 bearers may be fixed to the tree trunk, creating a level triangular platform
for the nest box to rest on. Use a third bearer to support the weight of the box and keep the platform level,
by fixing to the centre of the tree trunk underneath and the frontal point of the platform.
- Nails used to secure the bearers should be galvanized iron coated, so will not subsequently affect the
commercial value of the tree through staining.
- Do not be disappointed if barn owls do not adopt the nest box in the first season. If they are around and
Suffolk Wildlife Trust
Brooke House, Ashbocking, Ipswich IP6 9JY Tel: 01473 890089 Fax: 01473 890165
Email us at info@suffolkwildlifetrust.org or visit our website at www.suffolkwildlifetrust.org
Registered Charity No 262777
Living Landscapes, Living Gardens, Living Seas
Diagram A showing how the Barn Owl box fits together
Diagram B showing a crosscross-section of the box
Cut access hatch hole and reuse the hatch but reduce height by 0.75”
Line vertical sides of hole with 1.5” x 0.5” fillets on inside, projecting
0.75”
Form bottom location with 1.5” x 0.5” fillet fixed to inside face of hatch
Diagram C showing how the pieces of the box
can be cut from one sheet of plywood
Profile external shelf to ‘T’ shape
and screw fix to upper edge of
hatch opening
20.5” long solid timber fillet
angled to 60º and fixed to top
edge of roof Y
Cut roof X 1.25” longer than roof
Y with 60º angle on long side
Examples of barn owl nest box siting
Steve Piotrowski
Steve Piotrowski
Andrew Piotrowski
Bridget McIntyre
Thank you for your interest in helping your local barn owls. Please inform us when
your barn owl nest box is installed so we can ensure your barn owls are monitored by a
licensed Barn Owl Monitor. This will help to inform our conservation efforts for these
beautiful birds in the future. For more information about Barn Owl Monitoring and
bird ringing please see Suffolk Wildlife Trust information sheet about Barn Owl
Monitoring and the British Trust for Ornithology website www.bto.org/ringing/.
Please do not hesitate to contact Suffolk Wildlife Trust for further advice.
Suffolk Wildlife Trust
Brooke House, Ashbocking, Ipswich IP6 9JY Tel: 01473 890089 Fax: 01473 890165
Email us at info@suffolkwildlifetrust.org or visit our website at www.suffolkwildlifetrust.org
Registered Charity No 262777
Living Landscapes, Living Gardens, Living Seas