YANKTON, S.D. (KTIV) -- It's happened in places like Louisiana, Arkansas and Kentucky. Hundreds of birds mysteriously found dead.

Folks in Yankton, South Dakota, thought they were being added to the list after hundreds of dead birds were found there on Monday.  Turns out the unpleasant feathered discovery has a solid explanation.  They were poisoned.

Some had thought 200 starlings found dead in Yankton's Riverside park had frozen to death. But they were actually poisoned on purpose, by the US Department of Agriculture.

Many of the European Starlings discovered by a passerby, were lying on the ground or frozen in trees. Officials first thought the birds were late to migrate and froze to death during the recent cold spell.

But that theory changed after Yankton police received a phone call from a USDA official who said the birds had been poisoned.

"They say that they had poisoned the birds about ten miles south of Yankton and they were surprised they came to Yankton like they did and died in our park," says Yankton Animal Control Officer Lisa Brasel.

The USDA confirms the story, saying the deaths were part of a large killing at a private feed lot in Nebraska.

They say a local farmer had been having troubles with about 5,000 starlings defecating in his feed meal. Department of Ag officials say because of health concerns for the farmer's animals and staff they decided to kill the birds.

They used a bait laced with the poison DRC-1339. The USDA says the birds ate the bait then flew back to Yankton and died.

They say poisoning isn't a common practice.

"We're doing it to address, in this case, agricultural damage as well as the potential for human health and safety issues," says Carol Bannerman USDA Wildlife Services.

USDA officials say they regret they had to kill the birds. But say there's no toxic concern to people or animals.

In all, officials estimate nearly 2,000 birds ate the poison. However, since the bait has been removed they don't expect any more birds to die.

Online Reporter: Forrest Saunders