Tuesday, February 21, 2012

>Buteo albonotatus (Zone-tailed Hawk)

Zone-tailed Hawk

Zone-tailed Hawk
Conservation status
Scientific classification
(or Accipitriformes, q.v.)
Species:B. albonotatus
Binomial name
Buteo albonotatus
Kaup, 1847
The Zone-tailed Hawk (Buteo albonotatus) is a medium-sized hawk of warm, dry parts of theAmericas. It feeds on small vertebrates of all kinds (other than fish), including birds up to the size of quail.
Grown birds are 47–55 cm (18.5–21.5 inches) in length with a wingspan of about 1.2 m (4 feet); their average weight is 810 g (1.8 lbs). Adult plumage is mostly blackish except that the flight feathers are barred with lighter gray (appearing solid gray from a distance) and the tail has three or four bands or "zones", 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. Immatures are similar except for small white spots on the breast and tails with narrow gray and black bands and a broad dark tip. The Zone-tailed Hawk adults resemble the Common Black Hawk but are smaller and have more white bars on the tail.

The Zone-tailed hawk bears a superficial resemblance to the Turkey Vulture, pictured in flight.
The bird's plumage closely resembles that of the Turkey Vulture, and Zone-tailed Hawks soar with their wings held above the horizontal, rocking from side to side, like Turkey Vultures and often in company with them. As Turkey Vultures seldom prey on healthy animals, some ornithologists believe that this mimicry tricks potential prey animals into not being alarmed when a zone-tail flies overhead (Clark 2004). Bird guides caution against confusing it with the much more common Turkey Vulture, but at a reasonable distance one can see the smaller size, the typical hawk shape of the wings and head, and the pale stripe on the tail.
The call is a loud scream dropping in pitch at the end. In at least some birds, there is an abrupt rise in pitch (like a break to a falsetto voice) in the middle and an equally abrupt drop back down.
Zone-tailed Hawks range from parts of ArizonaNew Mexico, and western Texas to southern Brazil,ParaguayBolivia, and northern Argentina. In winter they generally withdraw from the U.S. part of their range. They sometimes wander out of their normal range, and the bird was once recorded inNova Scotia. Their habitat is canyons with open woods in arid or semi-arid regions, though birds may hunt outside of canyons.
The nest is typical of hawks: a big assemblage of sticks built in the leafy top of a tree (usually tall) or on a cliff. The clutch comprises two or three white eggs, often marked with brown.

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