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The peregrine falcon, also known as the peregrine, and historically as the duck hawk in North America, is a widespread bird of prey in the family Falconidae. A large, crow-sized falcon, it has a blue-grey back, barred white underparts, and a black head. As is typical of bird-eating raptors, with females being considerably larger than males. The peregrine is renowned for its speed, reaching over 200 mph during its characteristic hunting stoop (high speed dive), making it the fastest member of the animal kingdom.
Chicago Peregrine Program:
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Female peregrine falcon Louise, 3, hatched in Toronto's Canada Square site in Ontario, Canada, where she was banded in 2016. She was spotted in Malta, Illinois, and Jefferson County, Wisconsin, before moving on to Rockford. Gigi is MIA. He might have died, been driven off, or simply relocated. Louise has a new male. It's Lil Kool. Lil Kool, 4, hatched in 2015 at Thilmany Mill in Kaukauna, Wisconsin, one of four chicks in that clutch. Louise and Lil Kool have been spotted together since Good Friday, April 19, and have been mating.
Louise laid four eggs in 2019, on May 3, 6, 8 and 11 with her mate this year, Lil Kool. Three of the eggs hatched, on June 10, sometime between the evening of June 11 and early morning of June 12, and on June 14.
Louise and Gigi laid four eggs in 2018. The first egg was spotted on Thursday, March 29, 2018. The second egg was spotted on Monday, April 9, 2018, while the third egg was laid sometime between the afternoons of Wednesday, April 11, and Thursday, April 12, 2018. The fourth egg was laid on Saturday afternoon, April 14, 2018, and was recorded on video. Eggs are laid in 24- to 36-hour intervals. They can be varying colors, from a pale creamy to a dark, reddish-brown hue. The eggs are colored as they move through the female's oviduct as they press against glands that produce pigments. Patterns develop depending on whether the eggs are in motion when they reach these pigment glands. If they are stationary, the eggs become spotted. If they are in motion, the eggs will sport streaks. In each clutch, the first egg laid typically is darker colored because there was more pigment in the glands at the time vs. pigment available for the last egg.
In 1930, the famous architect Jesse Barloga built the News Tower at 99 East State St., which houses the Rockford Register Star. It was built as an homage to the Tribune Tower in Chicago. Today, most of the tower sits empty. Louise and Gigi chose to lay their eggs in a drainage channel on the building's exterior on the eighth floor.
Their nest sites in the wild usually are on cliff ledges and sometimes in the hollows of broken trees. In urban areas, they often use building ledges or even bridges. No actual nest is built with twigs or sticks, but the eggs are laid in a simple scrape. The scrape is a small depression made in the pea gravel or ground material by pushing their feet backward to dig out a little low area.
The bird of prey’s population was wiped out in Illinois by the 1950s and 1960s, due in part to the widespread use of pesticides like DDT. These chemicals caused egg shells to thin, resulting in breakage, as well as abnormal reproductive behavior in adult birds. Throughout North America at that time, peregrine falcons were close to extinction.
The birds were placed on the federal and Illinois endangered species lists in 1973, according to the Chicago Peregrine Program. The program launched in 1985, and released 46 birds into the wild between 1986 and 1990, according to The Field Museum. By 1988, there was believed to be only one breeding pair, in Chicago. Currently, there are at least 30 breeding pairs, according to The Field Museum.
It was in 2015 that peregrine falcons were removed from Illinois’ List of Endangered and Threatened Species. The peregrine population now is a threatened species under the Migratory Bird Treaty Act.