Bird flight as an identification tool
Paula Elliott sent in this great photograph of a male Eastern Bluebird exiting a nest box. The wings were no doubt folded as the bird exited the hole but it seems the bird can get an amazing amount of thrust from its legs.
The way a bird flies can be a clue to its identification. Birds like the Cooper's Hawk have a flap-flap glide flight pattern.
Woodpeckers are well known for their undulating flight. Small songbirds like the American Goldfinch also have an undulating flight as they flap and rest, flap and rest. This approach to flight is thought to save energy.
Turkey Vultures are on the other end of the size spectrum. These large birds are often observed soaring high overhead. They show a very shallow "V" shape when in flight. The field guides refer to this shape as a dihedral but that was always a little confusing to me. Turkey Vultures wing flaps are slow and deep. They also have a tendency to rock back and forth.
The similar Black Vulture tends to soar with flat wings. Its wing beats are shallow and more rapid than the Turkey Vulture.
Paula is also and excellent artist, check out her web site.