Utah wildlife officials have confirmed that a known poison killed hundreds of European starlings last month. Officials still don't know who used the poison called Starlicide.
Government agencies routinely kill starlings when flocks become a nuisance, but officials say they aren't responsible for the starlings that have been turning up dead around northern Utah.
The U.S. Department of Agriculture and the Utah Division of Wildlife Resources say that tests showed that Starlicide was used to kill about 400 starlings found dead at a Clearfield park.
Another 40 starlings were found dead in nearby Clinton on Wednesday, but officials say those birds showed different symptoms. Tests are underway to determine those deaths. Officials say anyone can kill starlings with approved poisons.