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, as well, vacillate on whether, that by providing specialty seed and suet, I am setting up my winter birds “for the kill” at the feeder. However, I provide a variety of cover, shrubs that berry in the winter, cover (trees and shrubs with thick brush), water (etc), and feel that it helps them survive the otherwise varying challenges of our northeast winter. Losses of a few, I hope, allows the many to make it through the winter.
Excellent article. We live on 60 acres in Healdsburg, Ca. We fill 4 large feeders a day The evergreen vines on our home provide perfect nesting, evening habitat and in the winter the ivy berries are a great food source for the Blue birds and Flickers . With food, water and habitat for breeding and roosting, we have a multitude of bird species on our property throughout the year. And yes, we have hawks….lots of them. Just today, a Coopers Hawk flew right over our feeders. We have less hawk /feeder issues (usually Coopers or Kestrels) when the trees have their leaves and do a better job sheltering the feeder area. So, even though we live in the ‘county’ we are following urban bird feeding protocol. And the theory about hawks and feeders is well supported on our property.
There has definitely been an increase in accipiter activity in my backyard, especially by the Cooper’s Hawk. I do not have exotic species using my feeders, so the Cooper’s Hawk shows a definite preference for Mourning Doves.
We here in Katy, TX (Houston suburb) are delighted to report a sharp decline of European starlings and house sparrows at our feeders and I’ve been wondering if it was because of the noticeable variety of hawks spotted circling the area. For several years starlings & sparrows were so heavily invasive we nearly stopped feeding birds altogether. This winter we have spotted very few! Finches & songbirds prevail. Yay!
Several red tail hawks haunt the woods in Riverside Park in Manhattan where I have feeders in a Forever Wild section of the park. I keep the feeders on twiggy low trees so that in winter (which is the only time I put out feeders) the hawks can’t gain access. They do hover around! I always know when they’re nearby because the house and white throated sparrows make a racket and hide in bushes; other birds just disappear. It causes a lot of drama but so far no kills. Lucy Warner
Great article! Gives me a perspective on the relationship that has developed between a Cooper’s Hawk, and my backyard. He has become part of the neighborhood, and my backyard bird experience. And he is very exciting to watch when he arrives.
A few days ago I heard the rush of wings which I thought might be the arrival of the Cooper’s Hawk, and the flushing of the Mourning Doves. When I went to investigate, I saw the Cooper’s Hawk trying to get a foothold on a hanging house-style bin feeder. It was flying first on one side, then to the other side. I thought he was just trying to get a foothold to perch on the feeder. Then I finally saw that there was a small bird trapped between the two clear plastic sides that houses the seed. The feeder was empty, and the bird had gotten inside, perhaps in its panic at the appearance of the Cooper’s Hawk. The hawk was unable to get at the bird protected as it was by the plastic. When the hawk left, I opened the roof of the feeder, reached in, and took hold of the small bird, an American goldfinch. I released it into the air, and it promptly flew up onto a 10K high-voltage power line crossing through my backyard. Not 40′ from the Cooper’s Hawk perched on the remains of a dead Aleppo pine in my backyard.
What a great article! Thank you!
I have had my bird feeders up out back in view from my kitchen table for three years.
Last spring, an interesting bird was perched on the fence near the feeders. It was a large bird with a hawk-shaped body and black and white dots on its wings and tail. In looking it up in several bird books, I found it was an immature sharp shinned hawk. I don’t know if it is that youngster now grown to adult that appears at my feeder from time to time, but I have seen evidence on the ground of its successful hunt.
The other morning, I was at my kitchen table looking out the window at the activity around the bird feeder, when suddenly there was an explosion of gray feathers. I ran to the sliding glass door and looked out to see a sharp shinned hawk standing on top of a band-tailed pigeon. The hawk tooked at me, I looked at it, and then it slowly lifted off, struggling to carry the weight of its prey. It went to the far side of the back yard and proceeded to enjoy its morning meal.
Your article eased my concerns about whether my bird feeders were really a good thing for the many birds that come and feed each day. I was feeling like it was somewhat of a set-up. My good intentions leading the birds to a place where they were easy prey for the hawk.
Thank you again for your article..
Beth Kraft
Novato, California
So, perhaps a stupid question, but…. while feeders have helped accipiter hawk populations, is it too harmful for the songbird population?
Hi Jenni, This is a great question! The researchers found no evidence that this predation is harming songbird populations. The bird feeders have actually increased population of some bird species. Also, a number of urban birds are not native (house sparrows, starlings, pigeons), and the hawks will prey on them pretty heavily.
I feed California quail (scatter seed) and pine siskins (finch sock). There is a strong presence of Red Shoulder Hawks here. The doves were the first to get eaten as they were the least aware birds. Now the quail are prey. Several broods of quail this year, more so than normal I think.
Very informative article! We live in a suburb of a small western city & see the Coopers & Sharp-shinned hawks regularly in the tall trees near the ditches where we have bird feeders. Glad for the information about the trend nationwide, & especially that the non-native birds are big targets for the predators.
Very interesting information and photos, and good news about cities providing lost habitat. Also, good to hear that the presence of predators in cities is helping to cut down on exotic species!
Hello, found a Cooper’s at my feeder in Tacoma Wa ( I believe a Cooper’s)
for the first time ever for me- daily for the last 3 days.
it lands
then hops to the ground and searches under the brambles- we have mice and rats too, due to chickens.
fyi
I have hawks at my feeders in Lake George NY, mostly red tailed and sharpies. Years ago in NJ I had them too and one sneaky Sharp Shinned would creep thru the shrubs near the feeders and lurk there until it was time to strike. One day he perched in the open on a tall pieris by my window and rested, but was watchful of the human audience. He looked right at me with his golden eyes – fearless stunning predator.
Since we have added a bird feeder (open plate based) We have seen a remarkable numner of birds including Blue Jays, red-headed Wood Peckers, Mourning doves (dozens at times),Robins (less so now), a variety of small birds, sparrows and the like, cardinals. We have also seen Hawks (as well as feathers indicting a Hawk was successful) and, occaisionally, Crows. The Crows have been observed to chase after a Hawk. In the summers, our Cannas provide nectar for humming birds.
Durand Park a passive use park is steps away. Many deer live in the park and have been a nuisance
Monmouth County, NJ
I would like to communicate with Dave about a special project in the Pine Barrens of New Jersey which brings back into the mix, small numbers of people moving into primitive areas , within the midst of higher population areas, when the people moving in are living more primitive lifestyles and thus blending in and actually enhancing the environment , in a sense similar to the Wolf Project in Yellowstone.
I am originally from New Jersey and go back there often. Presently I live in Iowa – the Hawkeye State.
In Truth in Nature
Steve Ulicny