Yesterday, I gazed out the window of my home office during a meeting, watching California quail and house sparrows forage beneath native sumac. Suddenly, the bush seemed to explode, with birds flushing in every direction.
A second later, a Cooper’s hawk deftly landed underneath the shrubbery. It began hopping around attempting to snag one of the remaining quail that hunkered down instead of flushing. But the hawk was just a little too late.
Over the years, I’ve noted more frequent sightings of both Cooper’s and sharp-shinned hawks around the neighborhood. You’ve probably noticed the same thing. Across the United States, these two hawk species – both similar looking and in the genus Accipiter – have increasingly colonized urban areas.
A new paper in the Proceedings of the Royal Society B sought to “identify factors that determine the occupancy, colonization and persistence of Accipiter hawks in a major metropolitan area.” In the course of their study, the researchers from the University of Wisconsin-Madison and Cornell Lab of Ornithology found that in the 1990s Accipiter hawks occupied 26 percent of sites around Chicago. After two decades, they occupied close to 67 percent of sites.
It’s a trend reported (often via citizen science) around the country. And a big part of it is the bird feeder in your backyard.
The Return of Raptors
By the mid-20th century, many raptor species, including Cooper’s and sharp-shinned hawks, had declined precipitously. Direct persecution and pesticides had taken a heavy toll. Decades of protection have caused populations to rebound, leading raptors including accipiters to reclaim habitat.
But as the birds spread, they found a new world: one of growing cities. One might initially conclude that predators would not find this new world to their liking, as it was covered in concrete and buildings instead of forests. And that’s certainly true for many wildlife species.
But, as the researchers note in their recent paper, cities present a mix of habitats, including backyards, parks and golf courses with plenty of space. These “novel ecosystems” provide opportunity for cover and also, often, for ample food supplies.
The researchers documented the spread of the two hawk species in Chicago via observation through remote sensing data and Project FeederWatch, a citizen science initiative that has conservationists record sightings throughout the winter.
Initially, the hawks colonized areas outside the city. But they increasingly spread to more and more urbanized areas. The researchers documented usage of areas defined by what they call impervious features: roads, buildings, sidewalks. The more impervious the area, generally, the less “green” habitat.
Initially, hawks avoided these highly developed zones. But eventually, as long as there was sufficient prey, they colonized even the downtown. Over the past two years, hawks went from the city fringes to occupying much of the metropolitan area.
The researchers hypothesized that reforestation would play a role in hawk recolonization. But it didn’t. In fact, wintering hawks preferred areas with fewer trees, perhaps to better hunt prey.
The Hawk at the Feeder
Bird feeding is a hugely popular urban pastime. More than 40 percent of U.S. households feed their backyard birds.
That creates an abundance of birds, concentrated in specific, predictable areas. A predator’s bonanza.
The researchers found that the predator’s persistence in urban areas was most influenced by abundant prey. Based on citizen science and other research across the country, hawks have taken advantage of the bounty of bird feeders across the country.
Cities are rapidly changing. The novel ecosystems they create are also highly dynamic and, often, poorly understood. Songbirds, like northern cardinals, may even expand their range due to feeders. Then predators recolonize, shifting species behavior and abundance.
The researchers cite studies in England that show the recolonization of Eurasian sparrowhawks in cities caused a dramatic decline in house sparrows as well as other species commonly found at bird feeders. The sparrows had exploded in population due to the free food sources and lack of predators. When the predators returned, it caused an immediate shift in the urban ecosystem. It’s not so different, really, than what happened when wolves were reintroduced to Yellowstone and found a park with an over-population of elk.
The researchers note that similar shifts in prey abundance might be expected in Chicago and other cities. Some studies have found that urban hawks are feeding heavily on European starlings, house sparrows and pigeons – all non-native species – so they could actually reduce competition for native songbirds.
Do bird feeders change migration patterns? At least one study found that sharp-shinned hawks on the East Coast were less likely to migrate due to the abundance of bird feeders.
Research into Urban Ecosystems is Vital for the Future of Conservation
Clearly, research into urban ecosystems is vital for the future of conservation. Understanding how species interact, and how species use new habitats, can help better design parks and refuges. Perhaps endangered animals that many consider incompatible with cities actually could recolonize urban areas if given a chance. After all, 50 years ago no one considered the Cooper’s hawk to be an urban bird.
And let’s not forget a key factor in helping scientists understand urban wildlife: you. The observations you make at your bird feeder, at the city park and along a greenbelt trail help researchers understand novel ecosystems and their wild inhabitants. While your observations may seem anecdotal, when combined with millions of other observers, they add up to a significant data set.
So, yes, you really are seeing more hawks at your bird feeder. Enjoy the show this winter: the restoration of the predator-prey dynamic to the urban wild.
What kind of bird feeder would you recommend that won’t feed squirrels or rats.
I live near the George Washington Parkway between Alexandria, Virginia and the Mount Vernon Estate. We have had several visits from Cooper’s hawks at our back yard feeder over the years. My wife and I enjoy seeing the hawks, and they aren’t near the problem for our birds that local cats are.
Come on to Minneapolis. We’ve been observing (without documenting much) exactly this along the Mississippi urban area. I’m sure our Christmas count over the years will offer all the proof you need.
Has anyone else witnessed a hawk striking or stooping on a squirrel? Last year I saw what I think must have been a Sharp-shinned hawk nearly nab a young squirrel that was gorging itself at a seed tray! This happened right on my deck, just outside my kitchen window. All the birds scattered when several squirrels moved in, and maybe that’s what caught the hawk’s attention (it caught mine). I was looking at the feeder when I saw a smallish hawk with a white and black striped tail and reddish chest and belly practically explode right above the squirrel-occupied seed tray on my deck railing, almost nabbing a young squirrel too intent on the seeds, and then chasing it closely as it dropped to the ground and ran and dodged frantically. Amazing! The lucky little squirrel managed to slip through a gap under the deck and avoid certain death that day.
Yes we live next to the Elwood Monarch butterfly preserver and I noticed no visitors to the niger seed bird feeder. Soon it was clear great photo of a Copper’s hawk perched on the feeder. It would be a brave and hungry finch to come to the feeder.
I have had feeding birds snatched off my sunflower seed feeder by both a Peregrine and a Coopers while I was looking out the dining room window. The Coopers nest in a neighborhood park and the Peregrines nest on the ledge of a tall commercial building in the Lloyd Center area of Portland Orygun.
Interesting! I have recently seen a beautiful Coopers Hawk lurking in the trees near my amply filled feeders, obviously enjoying the sight of all the little woodpeckers and finches conveniently gathering for him. We are in a suburban well wooded neighborhood.
Matt:
Thanks for the article. We are fortunate enough to have 4 acres of land in Canyon County and two acres are urban woodland that house at least one nesting pair of Cooper Hawks each year. Just by allowing the tress to grow and encouraging positive bird habitat we get to witness all of the benefits of urban wildlife, including; Bald Eagles this time of year coming off the Boise River, Osprey’s all spring and summer, an occasional Red Tail hawk, Ferruginous hawk, Banded Neck dove, Robins, English Sparrow, Gold Finch, House Finch, Chickadee, Junco, and of course Magpie. In the 25 years that we have lived at this address we have witnessed the residential encroachment that has taken away the farmland and with it the Pheasant and occasional Chukar. Even the California Quail numbers are down for the time being. But the best way I can think of starting a morning is with a cup of coffee, sitting on the deck (bundled-up this time of year) watching the sun come up and watching the birds come into the feeders for their morning meal and a drink at our backyard pond. The sounds and sights, even the occasional fly-by of a Cooper are a relaxing reminder that nature is still all around us. Even though the squirrels are a major nuisance.
At work in my northern Virginia suburban kitchen one afternoon this autumn, I heard a loud thud which shook the wall and sounded like impact between animal and glass. I ran to the family room and saw a 6-inch smear of goo and fluff on one of the french doors. I noticed a hawk making a slow landing on my neighbor’s lawn. On the ground twelve feet below my door lay a dead woodpecker. I assume the woodpecker saw the hawk and, in process of fleeing, flew full-speed into the door. The hawk stayed around for a few minutes, then flew away.
Your glass needs windows stickers of maybe a raptor for the birds to know it’s not safe to fly at( windows kill huge numbers of birds). The woodpecker would likely have avoided the glass and survived even the hawk which left the dead bird and likely killed another one in it’s place. Clean glass also increase bird kills I believe because it reflects open spaces and trees / bushes which the glass isn’t.
A very interesting, readable and formated story, it was not too long, but enough to chew on.
We see more Cooper’s Hawks in the city now that we used to. Our hometown is Owatonna MN. This bird will hit the side of our evergreen tree with open wings. Sparrows who sought shelter and safety in the trees will then fly out and the Cooper’s Hawk will catch the sparrow on the wing. What an awesome sight!!
I live in Long Island NY and yes the Red tailed hawks are now more. I see them along the parkways nesting and hunting. They also catch the doves from my feeders. But it is good to see them rebound from the 70s die off. I have even seen a Bald eagle on my journeys around the Island as a health aide. Thanks for the article.
Sincerely ,
Debra Domino.
Thank you for this information. We live in Santa Fe New Mexico & are in deed finding more hawks at our bird feeders & heated bird bath. We have had these visitors over the last decade. We actually moved our bird feeder,, but keep suet in the trees. The bird feeder is now in an area near a thick hedge & large trees where the small birds can hide with some cover to escape the hawk.
there is a Cooper’s hawk that sometimes frequents my neighborhood
Camden, Maine. Property surrounded by woods . Sharp-shinned OR Coopers yesterday at feeder – a first. Was within 20 ft with binoculars and still couldn’t decide. Chickadee feathers on snow, so guess hawk was not starving. Exciting, even thrilling to see this miracle of nature in hunting mode so close. Thanks for great article!
Bill Scoble