BOSTON -- Nearly two dozen birds found dead in Littleton were poisoned, according to veterinarians.

Bill Vales, an avid bird watcher, said he started finding dead starlings in his yard last month. He brought six of the dead birds to the Tufts Wildlife Clinic in North Grafton where veterinarians performed a necropsy, the Lowell Sun reported. They determined that the birds died from kidney failure after ingesting an avicide, a pesticide used to kill birds.

Researchers from Wildlife Services, a program under the U.S. Department of Agriculture, strategically placed the avicide, DRC-1339, in Littleton to prevent starlings from attacking a dairy farmer's feed.

"The concern is there are diseases spread to cattle by starlings," said Monte Chandler, state director of Wildlife Services, told the paper.

The avicide causes kidney and liver failure in birds, and they die after 72 hours. The avicide is metabolized, so it does not pose a serious threat to animals that could eat the dead birds, Chandler said.

Bacterial diseases spread by starlings can cause cattle to spontaneously miscarry, the paper reported.