VULTURE-MIMICKER
(Zone-tailed Hawk & a White-tailed Hawk

This week I decided to wander a couple of days in the mangroves and scrub. My friend Ismael drove me to the biosphere reserve's wildlife-viewing tower at Petén Tucha where I'd begin my hike. As we approached the tower we heard a squeal which Ismael instantly recognized as that of a White-tailed Hawk. This is a tropical species distributed from the US border to Argentina, specializing in open savannas and scrub.

Once we'd climbed the tower and had a view over the forest canopy we saw who was squealing. The White-tail had a fledgling lounging in a treetop and when the parent came near carrying food the young one would beg. It looked as if the parent were trying to entice the kid to fly out and try hunting itself but the kid seemed to prefer having its food brought to it.

The parent teased the fledgling awhile, then fed it, then began circling the nest area. While the parent was circling a Turkey Vulture wandered into the vicinity and to my surprise the adult White-tail began dive bombing it. The hawk attacked several times until the vulture sailed away.

"Why on Earth would a hawk be so hard on a poor old vulture?" I asked Ismael. To me it was just one of those many questions I scratch my head over every day, then move on. But, Ismael, knowing the local birds better and maybe having a sharper eye than I, kept quiet as he binoculared the bird and then finally said:

"No es un zapilote" -- "That's not a vulture."

I was taken aback. Of course it was a vulture, a Turkey Vulture with slender wings tilted in a V, a long, thin tail, a black bird with primaries and tail a little silvery... A common Turkey Vulture like those I've known since I was a kid watching them circling over our soybean fields in Kentucky!

"Look at the legs," he said. "They're orange... "

It was true. Moreover, now that I studied the bird more closely, something just didn't seem right.

Ismael was confused, too. He knew about a vulture-mimicking hawk here, the Zone-tailed Hawk, but that bird definitely has white feathers, while this one looked all-black. However, after we'd gone through all the possible species again and again we decided it had to be a Zone-tailed Hawk. For some reason we just weren't seeing the white feathers. Maybe it was the light. Also, my field guide said "...white tail bands of the adult are often partly concealed... " The book went on to say that sometimes Zone-tailed Hawks soar with Turkey Vulture flocks, further enhancing their deception, the idea being that prey will not hide if nothing but vultures are flying around. Zone-tails occur in a variety of arid and semi-arid habitats, wooded to semiopen, from the US border to southern Brazil.

So, the White-tailed Hawk had seen through the Zone- tailed Hawk's deception, even though I was so easily fooled. Moreover, now I know why the White-tailed drove off the Zone-tailed. My field guide says that Zone- taileds eat small mammals, reptiles, and BIRDS. The White-tailed parent hadn't wanted the Zone-tail to eat the squealing fledgling in the tree below.

You can see a White-tailed Hawk at http://www.mangoverde.com/wbg/picpages/pic30-182-5.html.

A Zone-tailed Hawk looking a little like a vulture is at http://www.schmoker.org/BirdPics/Photos/Raptors/ZTHA12.jpg.