Four baby peregrine falcons hatched in Evanston three weeks ago, and in three more weeks, they will be flying.
Their names are Wilbur, Lincoln, Dewey and Rosalind.
They're parents are angry because it's time for their new chicks to be removed from their nest high on a ledge-- and it could be very upsetting for mommy and daddy.
"We've been doing this for years, and it goes smoothly, and when we put the birds back in the nest, if anything the adults feel like ... I've been successful chasing that mean thing away from my kids," said Field Museum ornithologist Mary Hennen.
There are four new chicks this year and they will travel from outside to inside in a big brown box.
This is all about giving the three week old birds a physical and banding them with an ID bracelet that allows researchers to follow them for life.
This has been going on here at the Evanston library every year since 2004. This is the eighth hatching with two different sets of parents and now 24 chicks. Has this been successful?
"It's been extremely successful," Hennen said. "We've gone from zero in the state 23 years ago when we had a goal of three pairs and we have 23 pairs in the state."
The peregrine was basically extinct in the Midwest until the peregrine reintroduction program began in the mid-80's.
Now the bird is back showing good bloodlines.
"The blood is for DNA. We want to verify who's the dad," said Matt Gies, biologist at the Shedd Aquarium.
The three males, Wilbur, Lincoln and Dewey, and the one female, ROSALIND, are declared healthy and cleared for takeoff.
"They spend about three weeks with the parents learning how to fly, and then once they start hunting on their own they're gone," said Hennen.
After their physicals it's back to the nest, and soon, look out pigeons.