For many years the Barn Owl Trust has been concernedabout the way mouse and rat poisons are labelled and the increasing proportion of Barn Owls that are found to contain rodenticide. The latest figures from the Predatory Bird Monitoring Scheme show that a staggering 81% of dead Barn Owls analysed (mostly road casualties) contained traces of the more toxic Second Generation rodenticides. Whilst there is no doubt that some Barn Owls die as a direct result, very little is known about the effects of a sub-lethal dose.
Covering the subject of rodenticides in the Barn Owl Conservation Handbook we are producing has prompted the Trust to take a new approach in tackling the problem. We have written four short easy-to-grasp statements that we would like to see included on all Second Generation Rodenticide product labels:
1) Owls and raptors can be killed by the use of this product even if the instructions are strictly followed. This type of rodenticide was detected in 81% of Barn Owls analysed by the Predatory Bird Monitoring Scheme.
2) Please be aware that this product is slow acting and rodents are unlikely to be found dead at baiting points. Typically it takes between 3 and 14 days for poisoned rodents to die. During this time they will still be moving around the site, may move further a field, and may be caught and eaten by a predators such as Barn Owls. This is termed ‘secondary poisoning’.
3) Bait-covering will not significantly reduce the chances of secondary poisoning of predators that eat small mammals (Barn Owls, Kestrels, Red Kites, Stoats, Weasels, Polecats etc.).
4) This product should only be used as a last resort where other control methods, non-toxic products and less-toxic products, have been recently used and a rodent problem is still present.
Dr Alan Buckle who runs the Campaign for Responsible Rodenticide Use, an organisation set up by rodenticide manufacturers, has forwarded our request to all the major rodenticide companies and we have written to the Health and Safety Executive who are currently carrying out a review of rodenticide labelling requirements.