Dear Mr. Basham,
For Christmas I received the book, "Thunder Birds," written by Jim Arnosky. In his book Arnosky writes that the osprey has a body the size of a hawk, but it has wings nearly as long an the wings of an eagle. How can this be?
I enjoy your nature stories.
I am glad you received a book for Christmas, especially Jim Arnosky's book, "Thunder Birds." Arnosky came to the Gibson's Bookstore in Concord last year at the invitation of John LeDonne, the store's manager. Arnosky told us how he had traveled thousands of miles to study large birds of prey which he writes about in his book. Also, his drawings of birds are colorful and true to life. You are exceptionally bright to wonder how the osprey can have a body the size of a hawk, but can have wings nearly as long as the wings of an eagle.
First, the length of the osprey's wings does not mean they are extra heavy. Although they are very firm, the shafts of even the large feathers are hallow and extremely lightweight. You have heard the expression "as light as a feather."
Second, the breast muscles of birds are well developed, and even if the body of the osprey is the size of a hawk's, the muscles that move the wings have great strength. You may have seen small people who are surprisingly strong.
Third, the ends of the osprey's wings are equivalent to our hands. The osprey can turn the end feathers on its wings so that it can suddenly twist in flight and gain much maneuverability by making mid-air adjustments. The osprey, which is sometimes called a "fish hawk," can hover in air above open water. When it sees a fish loitering near the surface, the osprey can partially fold its wings to make a feet-first dive and spear the fish amid a gigantic splash. The osprey emerges from the spray in a helicopter-like lift-off with water dripping from the fish that is tightly clutched in the osprey's sharp talons.
Eagles can not make such sudden turns in flight to catch fish the way ospreys can and are know to steal fish from the ospreys.
Thanks for your question and continue to read about birds. When you are outdoors watch birds carefully as they fly. We have learned much about aerodynamics from birds.