Perfect Things

We were walking past a line of shorebirds on the harbor’s breakwater when my son stopped me and pointed. “Does that bird only have one leg?” About two dozen black turnstones — I didn’t recognize them at the time, I had to use All About Birds later — faced into the wind, broadside to the incoming waves. One of them was standing on one leg. We peered at the bird. Was that another leg tucked up against its belly? Hard to say. We studied the other birds. Most of them were standing on one leg, too. “That would be a lot of one-legged birds,” we told each other. We tried balancing on one leg. “Seems tiring,” we agreed. Why do birds rest on one leg? Researchers have suggested that this balancing act might help regulate heat. In a study of nine species, they found that birds with longer legs seem to rely on this strategy more often than birds with shorter legs, which have less leg surface area to keep warm. There were many things to wonder about on our walk home on two legs. For one, when do…