Winter can be a dangerous time for birds and this is not just because of the cold weather and a shortage of food. A growing, sinister threat also lurks in the form of rodenticides which are sometimes liberally laid in and around properties in the winter months to keep rats and mice at bay.
As I’ve learned in my own house with rats chewing electricity cables, the warmth of the human home can prove an attraction for rodents. But efforts to control rodents with poisons can be fatal for birds and mammals other than rats.
Some of the powerful chemicals on sale at the moment are also harmful to pets and even children.
The dangers of a new range of poisons, called Second Generation Anticoagulants (SGARs), have been known for some time but new research confirms they are spreading out of control throughout Australian ecosystems.
Scientists have found SGARs in tissue samples in a wide range of native birds from little penguins to black cockatoos but for species that eat rodents, like boobook owls and tawny frogmouths, SGARs are particularly lethal.
Poisoned animals spread silent-killer SGAR poisons around our parks, gardens, and local community before they die – and these lethal chemicals can take years to break down in the environment even after they kill. This exposes native animals to poisons that can result in tragic and avoidable deaths. SGARs are potent chemicals that cause internal bleeding in animals
The first generation of poisons were slower acting, needing several doses and did not necessarily poison predators down the food chain. Although SGARs might not also kill immediately, they can build up in an animal’s body for years before killing it. This means that poisoned animals can become walking time bombs spreading dangerous levels of SGAR poisons around.
Favourite animals like quolls and devils and birds including all owl speices and kookaburras, even beloved pet cats and dogs, are vulnerable to being poisoned by eating animals that have ingested SGARs. On the mainland, 60 per cent of the livers of dead powerful owls have been found to have dangerous levels of SGARs.
Vets have experienced spikes in treating pets for rodenticide poisoning during Australian mouse plagues in the recent past
Studies across Australia confirm SGARs poison native wildlife and pets, mirroring international evidence. In Tasmania, the threatened devil and the masked owl are under particular threat.
The Australian Pesticide and Veterinary Medicines Authority is considering regulating SGARs, as has already been done in the US and EU.
All products containing SGARs should be avoided. Safer alternative methods of rodent control are already available in Australia.in
Packaging for SGARs can be unclear, but as a safe bet avoid all products with the ingredients: brodifacoum, bromadiolone, difethialone, difenacoum or flocoumafen.
Birdlife Australia has been running a campaign drawing attention to the SGAR dangers. For further information, go to https://www.actforbirds.org/ratpoison