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.
I live a few hours south of Chicago and have noticed what I think is a Cooper’s hawk that checks out my bird feeders periodically. The birds clear out when he makes an appearance but the squirrels don’t seem to mind.
They are wonderful to watch- just got off a walk on the beach and saw a Red Shoulder,Cooper and Osprey.
Bill Mullen
Isle of Palms ,SC
My daughter lives at the edge of a small Vermont village near a wildlife area and a pond. An agricultural area that includes wetlands is nearby. She and her disabled husband enjoy feeding the many birds that visit their yard, and they provide something for everybody. Hawks have always been part of the mix: it is almost like a choreographed dance as the birds maneuver around each other. Those little birds are pretty smart, but the hawks have families to feed too, so we cheer them on. Another part of this performance are the crows who have established a relationship with my daughter, and wait patiently while she takes out her collection of bread scraps for them. They hang about, and serve as the “police force” for the bird-feeding area. When hawks and falcons show up, the crows seem to enjoy harassing them until they give up and leave. It’s always entertaining to be witness to these interactions among the avian community. A great learning experience for my granddaughter, too.
I’ve certainly noticed the more abundance of Coopers and Sharp Shinned hawks here in my neighborhood and at my feeders the last 2 years. Never had a problem with either of them in previous years. But they have found “good eating” and plenty of prey from the song birds at my feeders. They also have been taking a tole on my chickens in the back yard.
russell studebaker, tulsa,ok . 1/12/19
We live in the Hyde Park – Kenwood neighborhood of Chicago, south side near the lakefront and have regular visits from a Cooper’s hawk for the last three years when our bird feeders are out. We get sparrows by the dozens, some finches, chickadees (who will stick around, hopping about in the lilac bush and scolding the hawk!), and cardinals in the winter. The hawk flies into the yard and sits on the 7 ft wood fence searching for any birds that didn’t scatter fast enough. It will stay for 10-15 minutes at a time and then fly off. The park district has planted a lot of prairie plants along Lake Shore Drive and in Jackson Park during the past years. We have noticed more variety of birds in spring and fall stopping for a day or two while they are migrating.
Here in southern New Hampshire we see Hawks every now and then stalking the smaller birds that feed at our bird feeders. They are beautiful but we always root for the little ones to escape !
I am quite the active wildlife observer. I do think that hawks are being seen in urban areas more now than say eight to ten years ago. I do think bird numbers are declining and it’s not just because of hawks. There are numerous reasons. Mostly because of humans. Bird numbers will continue to fall and when there is a shortage of birds to satisfy our birds of prey, birds of prey will drop dramatically also. Enjoy your bird watching now. It will change.
We have lots of Coopers Hawks here in Tucson. Arizona along with some Harris Hawks and Red Tail Hawks. We especially see the Coopers Hawks in the Midtown areas where they appear to prey on pigeons and roost on parking lot lights and tall business buildings. Nice to know they are making a comeback. Btw, we also have Coopers Hawks in our neighborhood in San Diego California too.
We have lots of Coopers Hawks here in Tucson. Arizona along with some Harris Hawks and Red Tail Hawks. We especially see the Coopers Hawks in the Midtown areas where they appear to prey on pigeons and roost on parking lot lights and tall business buildings. Nice to know they are making a comeback.
The only problem is the increased hawk population is very hard on pigeon fanciers who fly their pigeons….the sport of racing pigeons is being ruined by the increased hawk population……they would go into my loft after birds…..
We have a trifecta of visiting hawks at our bird feeders, Cooper’s is the most common, followed by a few observations of Sharp-shinned Hawks. But the rare and exciting one is Merlin (a small falcon). They are very very fast and the birds seem even more frightened by them. When one started to visit last year the feeders were nearly abandoned for a while. I’ve seen one this year, but we have plenty of House Sparrows, so I hope it comes back and has a feast (I’d prefer to have fewer House Sparrows). The Cooper’s seem to prefer Mourning Doves here in Ohio.
I live in the Herndon/Reston, VA area. There is a Merlin that’s been hanging around the Trader Joe’s just off Baron Cameron Blvd. This bird seems to have been in the area for a month or more. This bird is very vocal. Seems like he is crying. Additionally, I just returned from MN this last week where I counted a dozen Red Tailed Hawks and an Eagle — all either on light poles lining the 494-highway or in the case of the eagle, flying over a bridge in St. Paul. Minneapolis is a great place to do urban birding for hawks, eagles, and other hunters. I’ve noticed that Herndon/Reston is good for Turkey and Black Vultures.
Cooper’s Hawks have learned to use our huge plate-glass windows to nab birds from our feeder-filled yard. The hawks Intentionally spook the small birds towards the windows. The persuing hawks know exactly where the windows are, and swing wide, then immediately circle back to grab any stunned bird. I witnessed this at least 10 times last year alone. It’s not just one clever hawk; I’ve seen both adult and juvenile hawks do it. I think a Sharpie has done it as well.
Feeding birds my whole life just loving it , now with the increase of hawks just to walk outside and hear the perfect silence of no birds . It’s somthing that’s it’s happening more often . Also I noticed that the hawk is not even fearful of me when I walk into the yard . I live next to the Greenbelt on Long Island New York, wondering how do I keep feeding these birds and not making it easy target for the hawk , nothing like the site of a hawk in the yard and a woodpecker planted against the branch of a tree ,not to move an inch amazing
LAST COUPLE OF YRS,HAD A COOPER”S HAWK VISIT OUR FEEDER 1-2 TIMES A WEEK,OK CAUSE MOST TIMES THEY GET A SPARROW OR STARLING–VEVAY,IN .