Zone-tailed Hawk is a large raptor of riparian areas, mountains, and arid hills of the Southwest canyon lands. They nest in large trees along creeks, in cactus in open desert, and sometimes on canyon walls. They are skilled aerialists, spending hours on end on the wing searching for prey. Sometimes they mix in with groups of the similar-looking Turkey Vulture, where they are passed over by birders without a second glance. They are thought to mimic Turkey Vultures in order to surprise prey that has become conditioned to the unthreatening vultures. In fact, Zone-tailed Hawks resemble and associate with Turkey Vultures in many ways; nesting in close proximity to vultures, and even roosting with them at times in winter. Zone-tailed Hawks hunt birds (doves in particular), mammals, and reptiles, usually captured through low-to-the-ground quick-drop stoops, but they also perch-hunt in the morning hours before thermals develop.
Zone-tailed Hawk is very similar to Common Black-Hawk as well, and they overlap in range and habitat. When perched, the two are confused for each other, but Zone-tailed Hawk is distinguished by its slimmer build with longer wings, gray (vs. bright yellow) lores, grayish-white tail bands dorsally, and shorter legs. However, the two differ drastically in shape when in flight. Zone-tailed Hawk is much longer and narrower-winged than Black-Hawk, with a longer tail. Zone-tailed Hawk is fairly uncommon as a breeder in the US, and withdraws south in winter with a few staying in south TX and southern AZ. Their call is a harsh, drawn-out kreeaaaaar!
Perched, is bulky with somewhat long tail.
Females larger than males.
In flight, extremely similar to Turkey Vulture but has slimmer body, slightly narrower wings and tail, and larger head.
In a moderate to steep glide, wings taper more sharply towards tips, and in shallow glide, show a straighter trailing edge to the wings, especially when facing away.
Very Turkey Vulture-like, buoyantly swaying from side to side but slightly less exaggerated.
Soars with a prominent dihedral often with tail closed, glides with a modified dihedral.
Exhibits slightly quicker, stiffer wing beats than Turkey Vulture, and more agile overall.
Two age classes; juvenile and adult. Take one year to attain adult plumage. All ages have dark eyes.
Differ from Turkey Vulture by banded flight feathers, yellow cere and feet, and tail pattern.
Adult is black below with heavily banded flight feathers and bold dark trailing edge. The tail has one prominent white band when closed from below. On spread tail, adult shows 2-5 inner bands. Males and females can differ slightly in tail pattern but not a truly reliable trait. Males often have a slightly bluer-cast to the back and chest than females.
Juvenile similar to adults, but have fine white spotting on breast or belly, finely banded flight feathers out to tips, and finely banded tail with wider black sub-terminal band. Sexes of juveniles identical.
Migration mainly from March through April in spring and throughout late August and September in fall, but is less understood compared with most species.
Some birds "overshoot' their breeding grounds in spring, and can be seen into central California and Colorado.
Seen in greater numbers than anywhere else in Veracruz, Mexico in fall, and Tubac, AZ in spring.
Most leave AZ and NM for Mexico and Central America, but a few winter along the Rio Grande Valley in TX west to CA at times.
(Map from Cornell Lab of Ornithology's All About Birds. For dynamic distribution maps, visit the eBird website.)