Sharp-shinned and Cooper's Hawks

It’s a good thing that we birders are not songbirds ourselves.  If we were, the great admiration that we have for hawks, eagles and falcons would be replaced by feelings of fear and dread at the smallest glimpse of one of these magnificently fierce predators.  And no other raptors strike fear in songbirds so much as the accipiters, a family of long-tailed, agile, mostly bird-eating hawks of which there are three species in North America.

In the southeastern parts of the United States, most of us have the chance to see at least two of the three accipiter species found in North America—the common and widespread Sharp-shinned and Cooper’s Hawks.  The larger Northern Goshawk strays only rarely into Mississippi.  It is typically an elusive bird of dense, mostly coniferous northern woods.  The unique plumage that the adult goshawk has makes it unlikely to be confused with its more common cousins.  However, the two smaller hawks are very similar in appearance.

In fact, these agile little hawks can look so frustratingly alike, especially in flight, that in making a call oftentimes the bewildered birder can only be certain that he/she has seen an accipiter.  An estimate of the bird’s size isn’t always of much help, either, because of the near overlap in the range of body lengths of Sharp-shinned and Cooper’s Hawks.  There is, of course, the difference between the species’ long tails: the Cooper’s Hawk’s is rounded; the Sharp-shinned’s is squared.  Sometimes this feature isn’t very noticeable or obvious, though, and that’s when knowing the differences in body shape between the two birds comes in handy.

Perched, a Sharp-shinned Hawk usually sits in a more upright position than the Cooper’s.  Its chest is proportionately wider and its hips narrower than its larger relatives.  It’s almost as if the little “Sharpie” has to make up for its diminutive size by adopting this straight, proud posture.  Another way you can tell the smaller species from the larger is by noting the leg thickness.  Sharp-shinned Hawks have very thin legs, a trait noticeable in even the large female birds that resemble Cooper’s Hawks.  Head patterning is a little different, too; the Sharp-shinned has a more extensive black cap than the Cooper’s, and on a brownish-colored immature bird the presence of a reddish cast to the head feathers indicates Cooper’s.

The proportionately long neck of the Cooper's Hawk is a useful feature in separating the species from the Sharp-shinned, especially when the birds are in flight.  Flight pattern can also be used as an identification tool, and the more experience you have with observing flying accipiters, the easier it becomes to distinguish the two species.  The Sharp-shinned Hawk has faster, more erratic wingbeats when compared to the Cooper’s Hawk, whose wingbeats are easier to count.

In my experience, it certainly isn’t easy to count feeding songbirds when a hawk decides to show up and check out the menu!  But then I guess we’d be ready to leave, too, if we  were those birds—or for that matter, if we were lizards, frogs, mice, rats, or insects.  All of these creatures are consumed by Sharp-shinned and Cooper’s Hawks, although to a lesser degree than birds.

Both the Sharp-shinned and Cooper’s Hawks declined perilously in numbers from DDT poisoning after World War II and were seen infrequently in Mississippi.  After the ban on DDT in 1972, their numbers steadily increased, and now they can be found commonly in the fall, winter and spring.  Cooper’s Hawks used to be fairly numerous and widespread as breeding residents in the state, but they are now scarce nesters in the summer months.

Part of the supposed scarcity could be from the fact that the hawks’ nests are tricky to find.  In mixed forest where the Cooper’s Hawk nests, it’s difficult to see through all the leaves that conceal the tree branches.  If you were to discover a Cooper’s Hawk’s nest, it would be a platform of sticks and twigs on a branch near the trunk of a deciduous tree.  The male hawk constructs the nest with some help from the female.  The brown-spotted eggs are incubated for 32-36 days, mostly by the female.  The resulting young hawks can fly after 27-34 days but are still dependent on their parents for over a month after that.

I said that the Cooper’s Hawks build their own nests, but there are always exceptions in the avian world.  Occasionally, these hawks will take the easy road and use an old crow’s nest.  Stranger still, a few nests have even been built on the ground.

I hope this article will help you appreciate the Sharp-shinned and Cooper’s Hawks even more, whether you see them darting through a dense forest, gliding high over fields or even stealthily hunting near your backyard feeders.  Just be very thankful that you’re not a little songbird!

Sources:

Birds of Mississippi.  Turcotte, William H., and Watts, David L.  University Press of Mississippi, Jackson.  Mississippi Department of Wildlife, Fisheries and Parks.  1999.

The Cornell Lab of Ornithology’s Guide to Birds of North America, version 3.  2001.

Field Guide to the Birds of North America, Third Edition.  National Geographic Society, 1145 17th Street N.W., Washington, DC.  1999.

Hawks, Owls, and Wildlife.  Craighead, John J., and Craighead, Frank C.  Wildlife Management Institute.  1956.