Cooper’s hawks (Astur cooperii) are crow-sized hawks that can sometimes be spotted in Cambridge and Somerville. Although most migrate south from late August to early November, it is becoming more and more common for some of these hawks to spend time here in the winter. Although these birds prefer forested locations, they increasingly hunt in the urbs (that should be a word) and suburbs.
In the past, people considered hawks to be either good or bad. Hawks that ate mostly rodents were good; hawks that preyed on songbirds, game birds or the occasional young chicken were bad. Because birds make up about 70 percent of the diet of a Cooper’s hawk, people considered them to be the worst of the bad hawks. People hunted them heavily.
In 1912, The Boston Daily Globe editorialized:
Every member of the hawk family has been regarded as an outlaw for many decades. Whenever the farmers of the Nation have seen a hawk, they have opened fire and have shot to kill. From Maine to Mexico, the mob execution of the hawk has gone steadily on for generations …
While there are some hawks that deserve death, there is no more reason for condemning them all than for condemning all Missourians because you knew a man from that State who was a criminal. There are … but three [hawks] that so deport themselves as to be detrimental to the welfare of man.
The Cooper hawk started all the trouble. The Cooper hawk is the outlaw that devotes most of its attention to the barnyard. It is the ordinary, widespread chicken hawk. It takes toll of the young of the hen throughout the country. It should be known by every farmer and should be shot on sight.
According to the Cambridge Chronicle of 1904, there were even bounties on Cooper’s hawks!
The commissioners on fisheries and game shall apply all money received from city and town clerks as follows: … One-third shall be expended for the payment of bounties to persons killing the goshawk, cooper hawk and sharp-shinned hawk.
As you can tell, people were not sympathetic to Cooper’s hawks, who were, after all, just trying to find the best niche in which to survive. They attempt to catch their bird prey while it’s in flight, and it takes an agile and swift flyer to accomplish this difficult operation – but these hawks have long tail feathers that act like rudders, allowing the bird to maneuver quickly even in dense forests. In addition, unlike many birds, their eyes face forward, which gives them remarkable depth perception and helps them catch prey at high speeds. Because of these physical traits, pigeons, sparrows and starlings should be constantly wary.
The Cooper’s hawk population was greatest in the late 1800s, but as the numbers of people grew, the numbers of hawks declined, reaching their nadir in the 1960s when farmers and scientists used DDT. (Thank this insecticide for eradicating malaria in North America after World War II, but it also harmed bird populations.) Today, Cooper’s hawk numbers are increasing once again thanks to protections and to our understanding of their value in keeping bird and mammal populations in check.
Cooper’s hawks often try to conceal their approach, hiding behind vegetation, rocks or trees as they fly just above the ground, ambushing unsuspecting prey. Sometimes they even fly upside-down! William Savage described one such encounter:
I was standing in thick brush, when suddenly I heard a loud rushing of wings, and, on looking around, saw a quail flying past at its utmost powers of flight and about twenty feet behind was a Cooper’s Hawk, pursuing with such rapidity that I could plainly see it was gaining on the quail. The quail was endeavoring to reach a clump of hazel bushes nearby. When about six feet above and directly over the desired covert, it suddenly dropped like a dead bird for the refuge. The hawk, however, was not to be eluded by this strategy, for with an extra effort, it shot beneath its prey, at the same time turning with its back next to the ground and spreading its murderous claws wide open, the quail actually falling into them; then righting up, sailed away with its prize. This I think was done in about ten seconds.
Many raptors kill with their beak. Cooper’s hawks hit their aerial prey at high enough speed that the impact alone is often fatal. (If it only stuns, Cooper’s hawks squeeze and crush the prey with their talons.) This can damage the hawk too, though. In one study of more than 300 Cooper’s hawk skeletons, almost one-quarter had healed-over fractures of bones in the chest.
Cooper’s hawks eat a lot – about 12 percent of their body weight each day. A 200-pound human would have to eat at least a dozen large pizzas per day to eat an equivalent amount. (A typical large pizza weighs 1 to 2 pounds.) One 6-week-old captive Cooper’s hawk ate nine sparrows and a mouse in one day and averaged eight sparrows per day until it was 10 weeks old. This bird refused water, presumably getting all the fluids it needed from its prey.
If you have a bird feeder in your yard, you might get regular Cooper’s hawk fly-bys. You can tell their age by the color of the eyes: They’re bluish in the young, yellow in young adults and red for older adults.
Have you taken photos of our urban wild things? Send your images to Cambridge Day, and we may use them as part of a future feature. Include the photographer’s name and the general location where the photo was taken.
Jeanine Farley is an educational writer who has lived in the Boston area for more than 30 years. She enjoys taking photos of our urban wild things.
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