Zone-tailed hawks are large soaring hawks native to the southwestern United States. Unlike their nearest relatives, when soaring they display slightly V-shaped wing postures and rock from side to side. That’s the same way turkey vultures soar. And like turkey vultures, zone-tailed hawks have dark bodies and two-toned under-wings.
Why do zone-tails seem to mimic turkey vultures and even frequently soar among them? The answer is thought to be a hunting advantage. A dove, lizard or chipmunk on the ground might ignore the presence of a harmless turkey vulture, which only eats carrion, soaring overhead, whereas the silhouette of a hawk normally sends small creatures scurrying for shelter. So, the zone-tailed hawk’s similarity to turkey vultures may allow them to sneak up on prey. It’s a variation on the “wolf in sheep’s clothing” strategy!
This is a compelling case of what’s known as “aggressive mimicry,” where a predator pretends to be harmless, as opposed to the more common “protective mimicry,” in which a mimic avoids being eaten by its resemblance to a dangerous or distasteful creature.
Zone-tailed hawks have been observed soaring in a group of turkey vultures, then suddenly plummeting earthward in a predatory dive. It’s easy to see how this “hawk in vulture’s clothing” approach helps the zone-tailed hawk capture unsuspecting prey on the ground. It’s a fascinating form of mimicry found in our natural world.
This Earth Note was written by Steve Schwartz and produced by KNAU and the Sustainable Communities Program at Northern Arizona University.
