How to Choose, Build, and Maintain a Barn Owl Nestbox

Updated

The Barn Owl Trust website (barnowltrust.org.uk) is the practical starting point for nestbox work in the UK: it covers where to put a box, how to build one, maintenance, and buying a ready-made box. Use it as your reference before you site, construct, or install anything, and follow its guidance rather than improvising, because box design and position strongly affect whether Barn Owls use it and whether chicks survive.

Where to place a Barn Owl nestbox

Placement is the part most people get wrong, so decide this before you build or buy.

  • Site the box for the owl, not for your view. The Trust's nestbox section covers where to put a box; treat its siting advice as the specification you are working to.
  • Think about the surrounding habitat first. A box is only useful if there is suitable hunting habitat nearby. The Trust's habitat pages explain how to manage land for Barn Owls, roosting and nesting places.
  • Check the box is safe from hazards. The Trust maintains a dedicated hazards and solutions section covering the different hazards affecting Barn Owls and what can be done — read it before fixing a position.
  • If you are unsure, get local input. The Trust's directory lists your nearest Barn Owl Group, Owl Rescue Centre, or Professional Surveyor, who can advise on siting in your area.

How to build a nestbox

The Trust provides build guidance in its nestbox section, including how to build one. Work from that design rather than a generic plan, because Barn Owl box dimensions, entrance size, and internal layout are specific to the species.

A sensible order of work:

  1. Read the Trust's nestbox guidance in full before buying materials.
  2. Build to the Trust's design, following its instructions on construction.
  3. Plan access for inspection and cleaning at the build stage — maintenance is much harder if you don't.
  4. Install only once you have confirmed the siting points above.

If you would rather not build, the same section covers buying a pre-made box, which removes the risk of getting the design wrong.

Maintenance requirements

The Trust's nestbox pages include maintenance as a distinct topic. Plan for it rather than treating installation as the end of the job:

  • Check the box periodically and keep it in the condition the Trust's maintenance guidance describes.
  • Keep records. The Trust asks that all Barn Owl nests, roost sites, and sightings (dead or alive), anywhere in the UK, be reported on its confidential survey website.
  • If you find an owl in trouble, don't handle the situation blind — the Trust's owl care section covers identifying the species, checking for injuries or illness, what to do next, and how to get help.

Getting help and further training

If nestbox work is part of a survey or mitigation project, the Trust runs professional courses:

Course Focus
Barn Owl Ecology, Surveys and Signs (BOESS) Foundation course covering ecology, legislation, surveying and basic mitigation
BOESS Add-on Practical In-person course at the Trust in South Devon, including surveying an active Barn Owl site
Advanced Barn Owl Surveying and Mitigation (ABOSM) Advanced surveying, mitigation, and report preparation

The Trust also offers talks and education for school, youth, and adult groups, and a directory of local contacts for finding your nearest Barn Owl Group, Owl Rescue Centre, or Professional Surveyor.

Quick decision guide

  • Want to act now, minimal risk: buy a pre-made box from the Trust's shop and follow its siting and maintenance guidance.
  • Want to build: use the Trust's build instructions, then follow its placement and maintenance advice.
  • Unsure about your site: check the habitat and hazards sections, then contact your nearest local group or surveyor via the Trust's directory.
  • Found an owl: go straight to the owl care guidance and the directory, and report the sighting on the Trust's survey website.