Date: July 15, 2016
Source: Field Museum
Peregrine Falcons, in their
normal habitat on isolated cliffs, mate for life. But some 25 pairs now nest on
Chicago skyscrapers and bridges, and city living has them in much closer
quarters than they used before humans dominated the landscape. A group of Field
Museum and University of Illinois, Chicago scientists investigated whether
typical breeding patterns hold true for these new city-dwellers and, in a paper
published in PLOS ONE, confirmed that even in the big city, the birds that
prey together, stay together.
"Peregrine Falcons that now
live in the Chicago region are living in very different conditions than you'd
normally see for these birds, so we wondered if the falcons' mating habits had
changed too. They're in much closer proximity to each other than they'd be in a
more rural environment, and we thought they might be more promiscuous with more
potential mates nearby," explains co-author John Bates, Associate Curator
of Birds at The Field Museum. "Each spring this population also has
migratory Peregrines passing through on their way to all parts of Canada, so we
didn't know what we were going to find, but it turns out that almost all of the
mated pairs in the city remain monogamous through the years."
Peregrine Falcons nearly went
extinct in the US in the 1960s due to thinning of their eggshells caused by the
pesticide DDT. However, historic egg collections at the Field and other museums
provided evidence for the harm caused by DDT, and it was banned. In the decades
since, reintroduction efforts have enabled Peregrine Falcons to make a comeback
in the Midwest, with populations thriving in urban areas in twelve states.
Ninety percent of the breeding pairs in the Midwest nest on buildings and
bridges in the Chicago area.
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