Zone-tailed Hawk

The zone-tailed hawk is a fairly large but slender Buteo hawk. Grown birds are 46 to 56 cm (18 to 22 in) in length with a wingspan of about 117–140 cm (46–55 in). The zone-tailed is comparable in length and wingspan to common large Buteos found to the north such as Swainson's and red-tailed hawk, but may weigh considerably less. Their body mass can range from 565–1,080 g (1.246–2.381 lb). In measurements, the sexes are close in size, but the female, at an average of 900 g (2.0 lb), is much heavier and bulkier than the male, at an average of 637 g (1.404 lb). Among standard measurements, the wing chord is 36.5–46 cm (14.4–18.1 in), the fairly long tail is 19.4–23.5 cm (7.6–9.3 in) and the tarsus is 6.7–7.8 cm (2.6–3.1 in). The adult plumage is mostly blackish. The notable exception is that the flight feathers are barred with lighter gray, which can appear solid silver-gray from a distance. The tail has three or four bands (the "zones" of the common name), white from below and light gray from above, of which the one second from the tip is particularly broad and conspicuous. The cere and legs are yellow, the lores are light gray and a light touch of white may be seen on the face. Immatures are similar except for small white spots on the breast and tails with narrow gray and black bands and a broad dark tip. …

Zone-tailed hawks range from parts of southern Arizona, New Mexico, and western Texas almost throughout inland Mexico and the central portions of Central America down into eastern Colombia, Ecuador, and more sporadically, into Peru, southern Brazil, Paraguay, Bolivia, and northern Argentina. In winter, they generally withdraw from the U.S. and northernmost Mexico, with these populations wintering mostly in Oaxaca and the Yucatán Peninsula. They are also native to the Caribbean island of Trinidad. The hawks of Central America may be seasonally migratory, although their movements are not well known. Zone-tails sometimes wander out of their normal range, and the bird was once recorded in Nova Scotia. They can adapt to various habitats across their broad range, including both closed and open ones and wet and dry ones. Often, the largest numbers are found in rocky areas with access to water. They often reside in coniferous or pine-oak forests as well as timbered canyonland, hilly riverine woods, dry open boscage and scrub, humid forests, and overgrown marshes. They may forage over ranches and even semi-desert, but always need at least scattered tree thickets for nesting. …

This hawk mainly preys on small birds and mammals (including bats, rats, mice, squirrels), but reptiles can be locally favored, including virtually any type of lizard, such as the common collared lizard, Yarrow's spiny lizard, the crevice spiny lizard, and the mesquite lizard. Among the rats preyed upon are the tawny-bellied cotton rat and the white-eared cotton rat. In the north, California quail, along with possibly other quail species, chipmunks, and other ground squirrels seemed to be the favorite prey. Other birds preyed upon include red-shafted flickers, acorn woodpeckers, eared quetzals, Steller's jays, yellow-rumped caciques, tropical kingbirds, and even eastern screech owls. Zone-tails also eat various young birds, having been observed preying on nestlings and fledglings of species as varied as herons and passerines. Zone-tailed hawks snatch young birds from trees or the ground without landing. Second-hand reports of predation on frogs, other amphibians, and fishes may be cases of misidentification of common black-hawks. Zone-tailed hawks are very active foragers, hunting almost exclusively by transects and random quartering in low flight at around 10–30 m (33–98 ft) over the ground. When approaching the prey, the hawk may try to use obstructing cover such as trees until it is within 0.5–2 m (1.6–6.6 ft) of the prey, an easy striking distance. …