Short-tailed Hawk
Encyclopedia
The Short-tailed Hawk is an American
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...

 bird of prey
Bird of prey
Birds of prey are birds that hunt for food primarily on the wing, using their keen senses, especially vision. They are defined as birds that primarily hunt vertebrates, including other birds. Their talons and beaks tend to be relatively large, powerful and adapted for tearing and/or piercing flesh....

 in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Accipitridae
Accipitridae
The Accipitridae, one of the two major families within the order Accipitriformes , are a family of small to large birds with strongly hooked bills and variable morphology based on diet. They feed on a range of prey items from insects to medium-sized mammals, with a number feeding on carrion and a...

, which also includes the eagle
Eagle
Eagles are members of the bird family Accipitridae, and belong to several genera which are not necessarily closely related to each other. Most of the more than 60 species occur in Eurasia and Africa. Outside this area, just two species can be found in the United States and Canada, nine more in...

s and Old World vulture
Old World vulture
Old World vultures belong to the family Accipitridae, which also includes eagles, buzzards, kites, and hawks.Old World vultures are not closely related to the superficially similar New World vultures and condors, and do not share that group's good sense of smell. The similarities between the two...

s. As a member of the genus Buteo
Buteo
Buteo is a genus of medium to fairly large, wide-ranging raptors with a robust body and broad wings. In the Old World, members of this genus are called "buzzards", but "hawk" is used in North America...

, it is not a true hawk
Accipiter
The genus Accipiter is a group of birds of prey in the family Accipitridae, many of which are named as goshawks and sparrowhawks. They can be anatomically distinguished from their relatives by the lack of a procoracoid foramen. Two small and aberrant species usually placed here do possess a large...

 and thus also referred to as a "buteo" or (outside North America) "buzzard". The White-throated Hawk
White-throated Hawk
The White-throated Hawk, Buteo albigula, is a bird of prey in the family Accipitridae, which includes the eagles, hawks and Old World vultures. In British usage it would be called a buzzard rather than a true hawk....

 (B. albigula) is a close relative and was formerly included in the species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 B. brachyurus.

Description

The Short-tailed Hawk is a small buzzard
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....

, about 16 in (40 cm) long with a 35-inch (90 cm) wingspan. Males average about 14 oz (400 g) and females approach 20 oz (over 500 g), but the size difference is slighter than in most birds of prey and the sexes are indistinguishable in the field. It has broad rounded wings, the tips of which are curved upwards while soaring, and a broad tail that despite the bird's name is of average length for a buteo in proportion to the body. Its call is a high-pitched scream similar to other buzzards.

One of the most interesting things about this bird is the melanistic
Melanism
Melanism is an undue development of dark-colored pigment in the skin or its appendages, and the opposite of albinism. It is also the medical term for black jaundice.The word is deduced from the , meaning black pigment....

 "black" phase – this species occurs in two colour morphs
Polymorphism (biology)
Polymorphism in biology occurs when two or more clearly different phenotypes exist in the same population of a species — in other words, the occurrence of more than one form or morph...

, with no intermediates. The dark form predominates in Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...

, where it is known as "little black hawk". The light form is common elsewhere in the species' range. In most of the North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

n buteos – e.g. the Red-tailed Hawk
Red-tailed Hawk
The Red-tailed Hawk is a bird of prey, one of three species colloquially known in the United States as the "chickenhawk," though it rarely preys on standard sized chickens. It breeds throughout most of North America, from western Alaska and northern Canada to as far south as Panama and the West...

 (B. jamaicensis) and Swainson's Hawk
Swainson's Hawk
The Swainson's Hawk , is a large buteo hawk of the Falconiformes, sometimes separated in the Accipitriformes like its relatives. This species was named after William Swainson, a British naturalist...

 (B. swainsoni) – melanistic individuals are known, although wholly black plumage is comparatively rare. Only in the North American population of Buteo brachyurus does it seem to be the prevalent form.

The adult light morph has dark brown upperparts. The underparts are white, except that the tail and flight feathers are grey barred with dark. The immature is similar to the adult but the face is streaked rather than white, and the tail bands are of equal width, whereas the adult has a broad bar near the tail tip.

The adult dark morph has black-brown upperparts and underparts, apart from the tail and flight feathers, which are grey barred with dark as in the light morph but possibly with darker grey. The young bird has the same tail pattern as the light-morph immature, and the underparts are spotted with white.

For a long time, it was thought that the dark phase of the present bird was a distinct species Buteo fuliginosus. For example, when Robert Ridgway discussed the Short-tailed Hawk collected at Oyster Bay, Lee County, Florida
Lee County, Florida
Lee County is a county located in the U.S. state of Florida. Located in southwest Florida, the principal cities in the county are Fort Myers and Cape Coral...

 by W. S. Crawford on January 28, 1881, the question whether or not the black birds were of the same species as the light ones was not yet settled.

Range and ecology

Short-tailed hawks breed in the tropical and subtropical 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...

 from southeastern 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...

 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...

 north through Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...

 to northern Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

, as well as in southern Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...

, USA. This species is generally found below 4,500 ft (c. 2,000 meters) ASL
Above mean sea level
The term above mean sea level refers to the elevation or altitude of any object, relative to the average sea level datum. AMSL is used extensively in radio by engineers to determine the coverage area a station will be able to reach...

 and most common below 2,500 ft (c.1,400 meters). It is replaced by the White-throated Hawk
White-throated Hawk
The White-throated Hawk, Buteo albigula, is a bird of prey in the family Accipitridae, which includes the eagles, hawks and Old World vultures. In British usage it would be called a buzzard rather than a true hawk....

 (B. albigula) in the Andes of southern Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...

 and south to central Argentina and Chile
Chile
Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...

; the Short-tailed Hawk is found in the Cordillera Central
Cordillera Central, Colombia
The Cordillera Central range is one of the three branches of ridges in the Andes Mountains that split in southern Colombia towards the north up to the Montes de Maria....

 and Cordillera Occidental of Colombia, while B. albigula occurs south of these locales. As far as is known, B. brachyurus is a year-round resident except that most of the Florida population migrates
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...

 in winter to the southern tip of the state, including the Keys
Florida Keys
The Florida Keys are a coral archipelago in southeast United States. They begin at the southeastern tip of the Florida peninsula, about south of Miami, and extend in a gentle arc south-southwest and then westward to Key West, the westernmost of the inhabited islands, and on to the uninhabited Dry...

.

Most of what is known about its natural history has been studied in the Floridan population, and might not apply to birds at the south of the species' range. In general, this species is associated with woodland, often near water.

It apparently eats mainly smaller birds. The Short-tailed Hawk hunts from soaring flight, often at the borders between wooded and open areas. A frequent maneuver is "kiting" – coming to a stop, the bird heads into the wind, with its wings held stationary. It typically attacks prey with a nearly vertical swoop, sometimes pausing and then continuing downward in a "stair-step" manner. Typical prey ranges from a New World warbler
New World warbler
The New World warblers or wood-warblers are a group of small, often colorful, passerine birds restricted to the New World. They are not related to the Old World warblers or the Australian warblers....

 (Parulidae) to a bobwhite (Colinus) in size. In Florida, icterid
Icterid
The Icterids are a group of small to medium-sized, often colorful passerine birds restricted to the New World. Most species have black as a predominant plumage color, often enlivened by yellow, orange or red. The family is extremely varied in size, shape, behavior and coloration...

s – namely the Red-winged Blackbird
Red-winged Blackbird
The Red-winged Blackbird is a passerine bird of the family Icteridae found in most of North and much of Central America. It breeds from Alaska and Newfoundland south to Florida, the Gulf of Mexico, Mexico, and Guatemala, with isolated populations in western El Salvador, northwestern Honduras, and...

 (Agelaius phoeniceus) and the Eastern Meadowlark
Eastern Meadowlark
The Eastern Meadowlark, Sturnella magna, is a medium-sized icterid bird, very similar in appearance to the Western Meadowlark. It occurs from eastern North America to South America, where it is also most widespread in the east.-Description:...

 (Sturnella magna) – make up the bulk of the prey. It also eats some frog
Frog
Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...

s, lizard
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...

s, large insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s, as well as the occasional smallish mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

, such as a rodent
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....

. Among the heaviest prey recorded are young Common Marmoset
Common Marmoset
The common marmoset is a New World monkey. It originally lived on the Northeastern coast of Brazil, in the states of Piaui, Paraiba, Ceará, Rio Grande do Norte, Pernambuco, Alagoas and Bahia...

s (Callithrix jacchus) and similar small monkey
Monkey
A monkey is a primate, either an Old World monkey or a New World monkey. There are about 260 known living species of monkey. Many are arboreal, although there are species that live primarily on the ground, such as baboons. Monkeys are generally considered to be intelligent. Unlike apes, monkeys...

s; these do not seem to form an important prey item however, and are only snatched when the opportunity presents itself.

The large stick nest is built in a tree; in Florida the Bald Cypress (Taxodium distichum) is a popular nesting tree of the Short-tailed Hawk. Its 1–3 eggs prer clutch
Clutch (eggs)
A clutch of eggs refers to all the eggs produced by birds or reptiles, often at a single time, particularly those laid in a nest.In birds, destruction of a clutch by predators, , results in double-clutching...

 are white, usually with dark spots and blotches.

The Short-tailed Hawk is uncommon and local in most of its range. But due to its wide extent of occurrence, it is not considered threatened by the IUCN.
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