Evanston’s Peregrine Falcons are Nesting

For the ninth consecutive year, a peregrine falcon couple has nested in a column outside the top floor of the , and in the past week the female has laid four eggs.

Falcons first began nesting in the upper reaches of the library building in 2004, and the current couple, Nona and Squawker, has been together for eight years.

Peregrine falcons mate for life and normally nest on cliffs. But after pesticides threatened the species’ population in the early 1970s, the birds sought out new suitable habitats, many settling on building ledges in urban areas.

For the past several years, the library has installed a camera (dubbed FalconCam) that monitors the falcons 24 hours a day. A live stream of the video can be viewed through the library’s website, and a devoted group of followers -- calling themselves the Evanston Peregrine Falcon Watch -- regularly monitors the birds, posting updates about notable happenings on an online discussion board.

According to these updates, this year, the falcons were first observed mating on Feb. 19, the first egg was laid on March 26 and a fourth egg was seen on April 3.

Based on patterns in the library’s records of past nesting periods, it normally takes four to five weeks for all the eggs to hatch. Fledglings are left untouched in the nest for nearly three weeks, at which time they are so that they can be tracked throughout their lifetime.

Each year, after famous Americans, librarians and literary characters.