Owls that eat poisoned rats can be poisoned themselves. And its not limited to owls; hawks and other birds of prey are routinely poisoned and die as the result of eating rats that have ingested rat poisoning. Other birds can also be poisoned if insects eat the rat bait and the birds then eat the insects.
The chemicals in question are used by professional pest-control operators. The chemicals are anticoagulant rodenticides (ARs)-, they work by interfering with the blood's ability to clot. Studies show that the toxins accumulate in birds of prey and other animals.
We ask the Environmental Protection Agency to ban the use of anticoagulant rodenticides in the United States as new studies suggest these poisons get into the food chain and can even kill endangered species.
SOURCE: http://www.nature.com/news/killing-rats-is-killing-birds-1.11824
