Zone-tailed Hawk
Encyclopedia
The Zone-tailed Hawk is a medium-sized hawk
Buzzard
A buzzard is one of several large birds, but there are a number of meanings as detailed below.-Old World:In the Old World Buzzard can mean:* One of several medium-sized, wide-ranging raptors with a robust body and broad wings....

 of warm, dry parts of the Americas
Americas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...

. It feeds on small vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...

s of all kinds (other than fish), including bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

s up to the size of quail
Quail
Quail is a collective name for several genera of mid-sized birds generally considered in the order Galliformes. Old World quail are found in the family Phasianidae, while New World quail are found in the family Odontophoridae...

.

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
Gram
The gram is a metric system unit of mass....

 (1.8 lbs
Pound (mass)
The pound or pound-mass is a unit of mass used in the Imperial, United States customary and other systems of measurement...

). Adult plumage
Plumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...

 is mostly blackish except that the flight feather
Feather
Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds and some non-avian theropod dinosaurs. They are considered the most complex integumentary structures found in vertebrates, and indeed a premier example of a complex evolutionary novelty. They...

s 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
Cère
The Cère is a long river in south-western France, left tributary of the Dordogne River. Its source is in the south-western Massif Central, near the mountain Plomb du Cantal...

 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
Common Black Hawk
The Common Black Hawk is a bird of prey in the family Accipitridae, which also includes the eagles, hawks and Old World vultures. It formerly included the Cuban Black Hawk as a subspecies...

 but are smaller and have more white bars on the tail.
The bird's plumage closely resembles that of the Turkey Vulture
Turkey Vulture
The Turkey Vulture is a bird found throughout most of the Americas. It is also known in some North American regions as the Turkey Buzzard , and in some areas of the Caribbean as the John Crow or Carrion Crow...

, 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
Falsetto
Falsetto is the vocal register occupying the frequency range just above the modal voice register and overlapping with it by approximately one octave. It is produced by the vibration of the ligamentous edges of the vocal folds, in whole or in part...

 voice) in the middle and an equally abrupt drop back down.

Zone-tailed Hawks range from parts of Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...

, New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...

, and western Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

 to southern Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

, Paraguay
Paraguay
Paraguay , officially the Republic of Paraguay , is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to the east and northeast, and Bolivia to the northwest. Paraguay lies on both banks of the Paraguay River, which runs through the center of the...

, Bolivia
Bolivia
Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...

, and northern Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

. In winter they generally withdraw from the U.S.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 part of their range. They sometimes wander out of their normal range, and the bird was once recorded in Nova Scotia
Nova Scotia
Nova Scotia is one of Canada's three Maritime provinces and is the most populous province in Atlantic Canada. The name of the province is Latin for "New Scotland," but "Nova Scotia" is the recognized, English-language name of the province. The provincial capital is Halifax. Nova Scotia is the...

. 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
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...

, often marked with brown.

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