Birds share with humans the trait of being bipeds of walking on their hind legs only. This has been highly successful for people since it freed up the front legs to do all the things we do with our hands. But this hasn't been an evolutionary option for birds, whose forelimbs have evolved into wings. In place of hands, birds have evolved a multitude of ways to use the neck, bill, and hind limbs. Mammals typically have only seven neck bones, making a long neck clumsy at best. Not birds, though, where neck vertebrae vary from 11 to 25—just try to get a giraffe to look as graceful as a swan!
Look closely at our desert birds and you'll see an amazing array of
tools—bills for cracking seeds, for probing into crevices, for catching insects
on the wing, for tearing apart flesh or drilling into wood after prey. Feet for
paddling, climbing, grasping. Or the feet of that trickster, the roadrunner, whose two
toes forward and two toes aft leaves you wondering if it's coming or going!
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.