Not many years ago, a Cooper’s hawk was considered a rare bird here. My copy of the Grand Forks County checklist, dated 2009, calls the Cooper’s hawk “uncommon.” Robert E. Stewart used the same word to describe its occurrence in the Red River Valley in his book, “Breeding Birds of North Dakota,” published in 1975. In 2005, an article in the Herald suggested Cooper’s hawks had been “nearly extinct” just 25 years earlier. That would have been 1980.
Today, the Cooper’s hawk is the most abundant raptor in Grand Forks.
It is perhaps not the best known. That description applies to the peregrine falcon. Those nesting on the UND water tower have become local celebrities. They are but one pair, however.
Nor are Cooper’s and peregrines the only raptors in the city. Great-horned owls are present, though exactly how many is tough to ascertain. Screech owls occur. So do merlins, smaller relatives of the peregrine falcon.
Their numbers don’t approach the population of Cooper’s hawks.
Tim Driscoll, the local raptor expert, has banded many of these birds, and he’s accumulated a mass of information about the species.
What accounts for the increase in numbers?
Cooper’s hawks have changed their ways.
“The Cooper’s hawk is a quintessential woodland hawk,” the authors of a monograph on the species in “The Birds of North America” declared, adding, “It is a secretive, inconspicuous species” that breeds “in extensive forests and smaller woodlots.”
Grand Forks is hardly an extensive forest, though it might qualify as a smaller woodlot.
Two changes have occurred in Grand Forks, however, that may have made the city more attractive to Cooper’s hawks. One is that the urban forest expanded and matured. For much of the city’s history, trees were limited to the floodplain of the Red and Red Lake rivers and to older, well-established neighborhoods. Trees were planted away from the river, including the UND campus, city parks and cemeteries, and these matured early in the last century. Rapid growth in the 1950s and 1960s brought a second wave of tree planting and created a wide expanse of open forest habitat.
Cooper’s hawks didn’t move in immediately, though. They responded to a second environmental change—the spread of bird feeding—also caused by human intervention.
The hobby has exploded in the last 20 years or so, increasing the number and variety of bird species nesting and remaining in the city. It also caused the birds to congregate in specific locations predators could find.
The Cooper’s hawk is a superb predator.
Its favorite prey is birds smaller than itself. This includes backyard birds up to the size of robins and mourning doves.
The Cooper’s hawks couldn’t resist this combination of habitat and a concentrated food source.
Of course, there’s been an impact on bird populations. What’s happened to the songbirds is among the most frequent questions I get.
The Cooper’s hawk is one answer.
Bird feeding has made the Cooper’s hawk an occasional winter resident here, as well, whereas earlier it had been considered a summer bird only, and not long ago even a rare one.
Cooper’s hawks have been widespread but rather thinly spread across the continent. Stewart thought them common in the Turtle Mountains and the Sheyenne River Valley, both places that qualified, even in pre-settlement times, as “extensive forests.”
The breeding range of the species extends northward past lakes Winnipeg and Manitoba.
The Cooper’s hawk is on my mind this week because one quite unexpectedly showed up at my place west of Gilby, N.D. It’s only the second of the species I’ve seen on my property.
Perhaps I shouldn’t have been surprised. My array of backyard bird feeders provides the concentrated food source the Cooper’s hawk seeks. My place would hardly qualify even as a “smaller woodlot,” however.
I imagine the bird was a stray from Grand Forks, which is about 30 miles away. I might have been able to determine that had I seen a band and recorded its color pattern. Driscoll has banded Cooper’s hawks reared in Grand Forks.
Cooper’s hawks are speedy, though, and I didn’t get such a close look.
The Cooper’s hawk is identifiable at glance. It’s a streamlined bird with a long, rounded tail and wings that are more or less perpendicular to the body. Thus, the Cooper’s hawk appears as a cross or a T-shape against the sky.