These two birds of prey belong in the Accipiter group. From the Latin word, Accipiter, meaning "bird of prey", these birds are the usual suspects that strike terror into the backyard scene. Their hunting strategies revolve around perching and watching for prey, soaring and then giving chase, or streaking in like a low level stealth bomber and picking out a likely candidate.
With short, broad wings these powerful fliers can chase down and overpower prey. Using their long, narrow tail feathers like a rudder, these birds can navigate through thickets and woodlands. Grasping prey with their talons, the birds use these talons to kill their meal. Although backyard bird feeding is a great pastime and way to get to know local birds, the motto if you build it, they will come, applies to both the songbirds dining on seeds and the predators that prey upon these sImageongbirds. So when placing bird feeders, think in terms of escape routes for the songbirds. This might be small trees or bushes, vines that they can penetrate or terrain that doesnít hem them in. Placing a feeder in the open or too close to windows makes it harder for the songbirds to avoid detection and to make a run for it.
One of the interesting features of the sharp-shinned and Cooper's hawks is the sexual dimorphism that exists between adults. Females of each species are larger than their male mates. This variation corresponds to the females being able to take larger prey like grouse, quail, small mammals and even fowl. At one point in time, the Cooperís hawk was known as the Chicken hawk for its tendency to pick off backyard chickens.
The males' diet may consist of birds the size of robins and jays, and also small mammals. Little songbirds like warblers or finches may elude the Coops, but they fall onto the radar screen of the sharp-shins.
Described in 1828 by a French biologist and ornithologist named Charles Lucien Bonaparte, a nephew of Napoleon Bonaparte, the bird was named for the New York-based naturalist William Cooper. Cooper was one of the founding members of the New York Lyceum of Natural History, which later became the New York Academy of Sciences. Bonaparte was studying birds in the United States when Cooper was alive, and he was noted for unsuccessfully getting John James Audubon admitted into the Academy of Natural Sciences. Later on in his life, Bonaparte wrote a 4-volume set on birds he collected and named for science in North America.
History aside, it doesn't matter to the jays and robins at the feeders that Bonaparte or Cooper existed. They are more aware of the terror that occasionally invades their backyard feeding. In addition to locating a feeder to minimize predation, another technique used to decrease visits is to stop feeding the birds if Cooper's hawks are prowling the neighborhood. As the songbird visits diminish, the hawks will move on to better hunting grounds.
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There are several other predators that cause consternation at backyard bird feeders. The small northern pygmy owl is another winter visitor that preys upon songbirds. This feisty little owl with the long tail and dark, false eye spots on the back of their head may predate on birds larger than themselves. What Iíve learned to watch for is a mob of songbirds scolding and being agitated around a certain spot in a tree where the owl is perched.
This mobbing strategy may seem counter-intuitive (the prey chasing away the predator), but there is strength in numbers. The owl uses the same cover that the songbirds utilize, so there is really little to do to prevent these owls from taking the occasional feeder bird. These birds will also migrate northward in the spring; another loosening of the backyard pressure.
The number one bird feeder predator is not a hawk or owl, but a beloved household pet ñ the family cat. Reverting to their wild heritage, feral or domestic cats prey upon millions of songbirds and small mammals each year. Studies have shown that even well-fed and well-loved cats that roam outside take birds. Instinct takes over when these pets encounter birds, and even if the bird isnít killed on the spot, many die from bite or claw infections. Not to pick on cats just because Iím a dog guy, their toll on songbird populations is much higher than the predation rate of the hawks and owls at backyard feeders.
The National Audubon Society and other conservation organizations endorse a "Cats Indoors" program, especially for folks that feed wild birds in their yard. They support separating cats from birds because of the catís natural tendency to stalk and attack wildlife as the best way to minimize bird predation. And providing escape cover for the birds is a strategy that works for cats and other predators.
Feeding birds in the backyard is a great pastime and activity that millions of Americans support; the selling of bird seed in North America is a multi-billion dollar a year industry. Enjoyment of these winged creatures in the yard is a common factor amongst those that feed birds, and with some careful placement of feeders and keeping cats inside, one that should continue to provide enjoyment for years to come.