i'm winging this one

I feed a Red-tailed Hawk everyday. When I first started several months ago, he wouldn’t even eat with me in the room. No matter how hungry he was, even if I put his food on his foot, he would not budge. After about four months of patience and persistence, he began to eat in front of me. Then, he took food from my hand. After another few weeks, he was standing on my hand and eating from it. To me, this was the ultimate act of trust. We had finally arrived.

But then, one day, he was standing on my glove eating and began to lose his balance. He spread his wings quickly to recover, and then looked me, expressionless, in the eye. He lowered one of his wings and rested it on my shoulder and turned back to his food. He finished his meal, one wing around my shoulder for balance the whole time. I could feel his stiff primary feathers against my neck and the heat from his light but powerful wrist. That hawk choosing to put his powerful wing around me was one of my favorite moments to date.

Over the past few months, I’ve been lucky enough to interact with raptors. I’ve spent many hours staring at them, falling in love with the eyes of a Great Horned Owl, the feet of a Bald Eagle, and the beautiful feathers of the Red-tailed Hawk. But what I’ve grown to appreciate most about birds is their wings. They need explanation to really understand.

A folded wing (baykidsmuseum.org)

When a bird is not in flight, you see only a small portion of their wings. They have them folded up tight, exposing only the tip. But under those feathers are the forearm, an elbow, and a humerus. These words should ring a bell, since they are parts of the human arm as well. As evolution would have it, bird wings evolved from limbs adapted for terrestrial locomotion- aka- arms.

Wings are highly adapted arms that are specialized for flight- so specialized that they are used essentially only for flying. Somewhere in the transition between arm and wing, several big adaptations developed. A sheet of skin grew on the inside of the elbow joint, providing more surface for lift and limited motion between the humerus and forearm. This skin is called the patagium.

Comparison between human arm and bird wing

The wrist bones fused and elongated, forming the carpus (the portion that is exposed when a bird’s wings are folded). The bones of the hand reduced in number, as did the phalanges. They shifted to be in line with the carpus and lost almost all flexibility. And the feathers; we can’t forget about the feathers.

Flight feathers sprout posteriorally from the limb. The large primary feathers toward the tip of the wing sprout from the bird’s “hand” and help provide thrust, pushing the bird forward through the air. Secondary feathers are the large ones that sprout from the forearm. Their flat, boxier shape provide upward lift- not unlike the wing of an airplane.

Bone positions in an extended wing

To me, these things are not easy to understand just by looking at a bird sitting there. You have to extend the wing, fold it back up, extend it, and fold it back up several times to appreciate how the segments are put together and how the feathers fit into the whole picture.

Even in flight, it takes keen observation to understand. Most of what you see is feathers- the actual wing ends way before the feathers do. When a bird is flying, the outstretched forearm and humerus can appear to be one segment. But if you ever have the opportunity to feel an outstretched wing, you can trace the bones with your fingers and clearly feel that elbow joint. It’s there, disguised by feathers and that tricky patagium.

After studying a bird’s wing, it will make you want to cut the Wright Brothers a break. The complex and precise design of a bird’s wing is a tough thing to replicate for us clumsy humans. I think we’ll have to leave graceful flight up to the birds and their elegantly evolved arms.