Wednesday, May 25, 2016

Sharp-shinned and Cooper's Hawk comparison

On May 8th I spotted a late Sharp-shinned Hawk being attacked by a much larger Cooper's Hawk. I don't often get to see these birds together. They are quite similar. Females are quite a bit larger than males. The large female Cooper's is biggest, bigger than a crow. Next, the male Cooper's and female Sharp-shinned are very similar in size, somewhat the size of a pigeon. The male Sharp-shinned is the smallest--jay-sized. And the typically solo bird can be hard to estimate as to size, so misidentification, or lack of specific identification, is frequent among even experienced birders.

The tail of the Cooper's Hawk is rounded, while the Sharp-shinned Hawk has a square tip.

In relaxed flight or gliding, the Cooper's Hawks hold their wings out rather straight, with the head and neck projecting far in front of the straight leading edge of the wing--like a large flying cross. Contrariwise, the Sharp-shinned Hawk holds its wings forward at the wrist. The wrists then project forward nearly as far as the head on a short neck.

In the (not-very-good) chase photo below the Cooper's Hawk is flapping rapidly and has its wings extended forward, but the Sharp-shinned Hawk has the typical flight profile.

ID: Comparison of Cooper's and Sharp-shinned Hawk
Female Cooper's Hawk attacking male Sharp-shinned Hawk. Escondido, California. May 8, 2016. Greg Gillson.
At any rate, when reporting a Sharp-shinned Hawk this late in the spring in southern California, it is very helpful to have a photograph for proof--especially a comparative shot like this!