In a study released late last year, University of Wisconsin researchers revealed that hawks, once in decline as a species, have recovered in numbers substantial enough that they are successfully expanding their territories into urban areas in Chicago.
Using data from decades of sightings faithfully reported by feeder watchers like Noe, University of Wisconsin professor of forest and wildlife ecology Benjamin Zuckerberg was able to show that only 20 percent of feeder watchers in the Chicago area spotted a hawk during the 1990s. Today that number is closer to 70 percent.
“Hawks like the Cooper’s and sharp-shinned (a similar, smaller species) are classic woodland hawks,” says Zuckerberg. “They were always traditionally thought about as these species that were really well adapted to big, uninterrupted forests. They’re the quintessential woodland predators.” Which is why Zuckerberg was surprised to see numbers rising sharply in city neighborhoods. “It turns out that many of these hawks are able to use urban areas, which is sort of unusual because you wouldn’t expect them to be able to use an urban habitat.”
One factor that makes Chicago a hospitable home for hawks, Zuckerberg says, is that “they have enough prey.” Larger and more common red-tailed hawks will hunt pigeons, rabbits or rats in alleyways and elsewhere in the city — they have even been spotted hunting alongside the “L,” following trains that flush out pigeons. But for Cooper’s hawks, which typically specialize in prey about the size of a robin or dove, bird feeders are key. “Now that you’ve got a lot of people feeding birds,” says Zuckerberg, “the secret is sort of out for these hawks.”