Wildlife

Barn Owl Conservation in 2025: Nest Boxes and Poison

The barn owl is a UK conservation success story in many respects, but rodenticide secondary poisoning and habitat loss continue to limit population recovery.

Key Facts

UK barn owl population has recovered from under 4,000 pairs in the 1990s to approximately 12,000 today
Recovery is partly attributed to the nest box network maintained by the Barn Owl Trust
Second-generation anticoagulant rodenticides (SGARs) are detected in 70-90% of barn owl carcasses tested
SGARs cause internal bleeding and can cause death before the toxic dose is consumed
Rough grassland within 100m of nest boxes is the most important foraging habitat requirement

Welfare Considerations

Barn owls poisoned by SGARs die over days from internal haemorrhage — a prolonged welfare event that is invisible to observers until the bird is found dead or incapacitated. The prevalence of SGAR contamination in wild barn owls is so high that sublethal effects (reduced hunting efficiency, immune compromise) likely affect reproduction at the population level. Switching to first-generation rodenticides or non-toxic control methods directly reduces this welfare burden.

What You Can Do

Install barn owl nest boxes on farmland with rough grassland — follow Barn Owl Trust guidance
Switch from SGARs to first-generation rodenticides or physical pest control where possible
Report SGAR-poisoned barn owls for post-mortem testing to the Predatory Bird Monitoring Scheme
Support the Campaign for Responsible Rodenticide Use (CRRU) stewardship scheme
Donate to Barn Owl Trust nest box and monitoring programmes