Cooper's Hawk

(Accipiter cooperii)

Cooper's Hawks are designed for hunting in a forested habitat. Short, rounded wings, and long tail help this accipeter maneuver with speed among the trees as it hunts for prey. The adult hawk in this first image was watching a group of quail moving through the blackberry brush below. It is interesting to note that flying at high speeds through wooded areas sometimes proves to be hazardous to the birds -- in a study of more than 300 Cooper’s Hawk skeletons, 23 percent showed old, healed-over fractures in the bones of the chest, especially of the furcula, or wishbone. The Cooper's Hawk gets its name from the American naturalist William Cooper (1798–1864), one of the founders of the New York Lyceum of Natural History which later became the New York Academy of Sciences (Cooper collected the first specimen of the species in 1828).

With a diet of mostly other birds (and occasionally small mammals), they are often seen hanging around backyard bird feeders waiting for their next meal to arrive. Over the years Cooper's Hawks have adapted to living near humans and are now fairly common urban and suburban birds. One of the human caused hazards to Cooper's Hawks and other raptors has been ingesting rodenticides from poisoned prey. Accumulation of these poisons can cause liver damage and a slow death from internal bleeding. Recently as 2015, some EPA restrictions were placed on these substances that may help reduce numbers of deaths caused by this type of poisoning. To read more about this subject follow this link (Raptors and Rat Poison).

Due to its similarity to the Sharp-Shinned Hawk the Cooper's Hawk can prove to be a challenge for an untrained eye to ID. In general Cooper's Hawks are larger in size than the Sharp-Shinned, have a rounded tail compared to the square tail of the Sharp-Shinned, and have a dark gray cap on their head that is distinct from their pale gray nape and neck area. For more information about how to determine the identity of a Cooper's Hawk versus a Sharp-Shinned species visit this helpful link (Project FeederWatch, tricky bird IDs, Sharp-shinned Hawk and Cooper’s Hawk). (All efforts were made to correctly ID the hawks in the photos of this posting however it is possible that mistakes were made -- if found please note correction and send to the contact us section of this blog.)

Adult Cooper's Hawk in Flight

Description Diet Migration Nesting

Adults have red eyes, blue-gray coloring on their head, neck, and back with reddish bar markings over a white breast.
Juveniles have yellow eyes, brown coloring on their head, neck, & back with a white breast streaked with brown on the upper areas.

Length: Male = 1 ft 2.6" to 1 ft 3.4" Female = 1 ft 4.5" to 1 ft 5.7"

Weight: Male = 7.8 to 15.5 oz Female = 12 to 25 oz

Wingspan: Male = 2 ft 0.4" to 2 ft 11.4" Female = 2 ft 5.5" to 2 ft 11.4"

Lifespan: The oldest Cooper's Hawk was a male and at least 20 years, 4 months old. It was first banded in California in 1986, and found in Washington in 2006.

Diet consists mostly of other birds. Has a preference for medium sized birds, such as doves, quail, jays, robins, starlings, pheasants, grouse, and chickens. Cooper’s Hawks residing in the West will also eat mammals. Kills prey by repeatedly squeezing it with its feet/talons. Also has been observed drowning prey. Often leaves signs of where it has eaten its prey by a pile of feathers left on the ground below where it has perched to pluck the feathers from a kill.

Short to medium-distance migrant. Many hawks stay close to the same location year round but northernmost birds will migrate south for the winter, flying by daylight. In certain weather conditions migrating hawks will concentrate along ridges and coastlines, especially in the fall. Some hawks migrate as far south as southern Mexico and Honduras.

Nesting site is typically 25-50 ft up within trees like pines, oaks, Douglas-firs, beeches, or spruces that are found in dense woods & on flat ground rather than hillsides.

The nest is built primarily by the male over a 2 week period.

Nest is made up of piles of sticks ~ 27 inches in diameter and 6-17 inches high. Within the middle is a cup-shaped depression that is 8 inches across, 4 inches deep, and lined with bark flakes & green twigs.

Clutch size: 2 to 6 pale blue to bluish white eggs. 1 brood per year.

Incubation: By the female 30 to 36 days. The male incubates the eggs for a few minutes while female is eating. At hatching, chicks are covered in white down, weigh 1 ounce, and able to move about nest. The male provides nearly all the food to the chicks and female during the next 90 days up until the fledging period.

Fledging: 27 to 34 days.

Juvenile Cooper's Hawk

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References

1. "Cooper's Hawk, Life History". All about birds, The Cornell Lab of Ornithology. Cornell Lab of Ornithology. Retrieved October, 2016.
2. "Cooper's Hawk". Audubon Guide to North American Birds. Retrieved October, 2016.
3. "Cooper's Hawk". Wikipedia, The Free Encyclopedia. Retrieved October, 2016.
4. Bell, Cathy. July 15, 2015. "Raptors and Rat Poison". Living Bird Magazine, Summer 2015. Retrieved October, 2016.

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