Nature Notes

BY ANDREW BEREZIN

In West Texas summers it’s easy to spy a flock of turkey vultures gliding along currents of air searching for their next meal of dead animal carcass. But few realize that a Zone-tail hawk could be disguised among the circling vultures. 

Zone-tail hawks look similar to the turkey vulture, using this mimicry to aid them in capturing their prey. Zone-tails hunt by hiding within a group of turkey vultures, waiting until they see below prey which is unaware of the hawk hidden among the harmless scavengers.

Quickly, the zone-tails leave the flock and dive upon their next meal, usually lizards, rodents or small birds. With their keen eyesight, zone-tails can locate their prey while flying more than three hundred feet above the ground.

Zone-tail hawks are a medium sized raptor usually just under two pounds with a wingspan up to four feet. At a distance, zone-tail hawks closely resemble turkey vultures as they are mostly black and rock their wings when they soar, but there are differences: Zone-tails have white bars across the large wing feathers and white bands in their tail feathers. Unlike Turkey vultures, zone-tails have a fully feathered head.

Zone-tails can be found across the drier parts of the Americas. They are a common bird world-wide, but they’re uncommon, even rare, in the Trans Pecos region of Texas.

Zone-tails spend the winters in the warmer climates then return north to breed during the warm summer months. 

Once their spring migration is complete and breeding territories established, male zone-tails will attract mates by performing elaborate courtship rituals. These displays often involve an elaborate show of aerial acrobatics at elevations of 1,500 feet or more.

 After a suitable mate is found, zone-tail hawks construct large nests in the tops of trees using sticks and small branches. They also nest on canyon walls and cliff faces such as those along the Pecos River and in the many canyons in Big Bend National Park. 

A breeding pair may reuse the same nest sites for several consecutive years. A breeding pair of zone-tails can be quite protective of their nests, attacking intruders such as Red-tail Hawks, Golden Eagles and even humans that come too close.

Females lay a clutch of one to three eggs and incubate them for about 35 days. But the female does not do all the work. The male zone-tail hunts for both the female and the young. The young will remain in the nest for six to seven weeks until they can fly and hunt for themselves. 

Zone-tail hawks nest in mountainous areas or other rugged terrain but generally hunt in more open habitat like our desert grasslands. Several Zone-tail sightings have been reported over Kokernot Park in Alpine as well as above Hancock Hill on the Sul Ross campus.

Next time you see a flock of turkey vultures soaring in the sky, take a closer look at the flock. There may be a hidden surprise inside and a chance to observe one of nature’s many remarkable creatures. 

Nature Notes presents natural wonders of the Chihuahuan Desert in this column every other week. Nature Notes is produced by the Chihuahuan Desert Research Institute and Marfa Public Radio and is sponsored by the Meadows Foundation and the Dixon Water Foundation. 

Tune in to Nature Notes on KRTS-93.5 FM on Tuesdays and Thursdays at 8:35 a.m. and 4:45 p.m. and again on Thursdays at 7:06 p.m. Visit us online atnaturenotesradio.org.