Necropsies will be performed on four peregrine falcon chicks that hatched recently on a building at the University of Illinois at Chicago and were found dead last week.
The Chicago Peregrine Program shared the news on social media under the headline “Heavy Hearts.”
Writing, “it is with deep regret that we announce the loss of Chicago’s UIC peregrine chicks.”
The cause of their deaths is unclear.
Mary Hennen, the director of the Peregrine Program, says the adults seem to be fine.
“Losing all four at once leads me in the direction of thinking that it’s probably something along the lines of contaminated prey, she said. “That could be either they were fed a poisoned pigeon or they were fed a bird that contained bird flu.”
Hennen said the adults don’t always eat what they feed the chicks and they’re healthy, strong birds that can handle more than their young.
There have been nesting peregrines for more than 25 years at UIC.
Chicks hatched there have been banded and have gone on to raise their own broods.
There’s a male named Richardson that’s part of a nesting pair in McKinley Park.
He was hatched at UIC in 2014.
“As hard as it is to lose a complete clutch of chicks this way, you want to look at the whole picture, she said. “We have other pairs that are being successful breeding and that’s a great thing to have.”
Hennen said there are about 20 nesting pairs in the Chicago area and another 10 elsewhere in the state.
Hennen is the assistant collections manager for the Field Museum’s bird division.
She says they’ll try to determine the cause of the deaths after the field work season is over.