Tuesday, February 02, 2010

Interesting Shadow

A break in the clouds today produced an interesting shadow. Scout was sitting on top of the nestbox and projected on the back wall of the nestbox was a clear shadow of her tail and wing tips. The shadow illustrated just how long the wings of a peregrine are.

This is remarkable because I often get calls from people reporting a peregrine falcon they saw in their backyard. While such a report is certainly possible, it is far more probable that the typical suburban caller observed a Cooper's hawk--not a peregrine. These two species of raptors are similar in size and plumage and both prey on small birds, thus they are often confused. But the main difference between the 2 species is how their bodies are built that defines the typical niche they hunt in. Cooper's hawks have short wings and a long tail that is used as a rudder to maneuver amongst trees and shrubs found in the typical backyard. Peregrines, on the other hand, have extremely long wings and a short tail. They need a wide open space to pursue their prey and wouldn't do well chasing a songbird through tree branches--their wings would simply get caught up in the tangle.
This difference in their wings and tail is extremely evident when one knows what to look at. When the bird is perched and wings folded against the body, notice where the tip of the wings fall in relation to the tip of the tail. On a Cooper's hawk, the tail will extend several inches beyond the end of the wings. On a peregrine, the wing tips will be as long or even longer than the tail. I thought Scout's shadow today showed how long the wing tips are on a peregrine in quite a unique way.