White-tailed Hawk
Encyclopedia
The White-tailed Hawk is a large bird of prey
species
found in tropical or subtropical environments across the Americas
.
hawk
. Adult birds are grey above and white below and on the rump, with faint pale grey or rufous barring. The short tail is white with a narrow black band near the end that is conspicuous in flight. A rusty-red shoulder patch is just as characteristic when the bird is sitting with wings closed. The wings are dark above, admixed with grey near the bases of the blackish primary remiges. The underwing is whitish, with indistinct brownish barring on the underwing coverts that extends onto the flanks and thighs. The iris is hazel, the cere
is pale green, the beak
is black with a horn-colored base, and the feet are yellow with black talons.
Immature birds are somewhat darker than adults; they may appear nearly black in faint light, in particular individuals which have little white below. The wing lining is conspicuously spotted black-and-white; the rusty shoulder patch is absent in younger birds. The tail changes from brown with several dark bars to greyish with a hazy dark band as the birds approach maturity. The bare parts are colored much like in the adult.
Its call is a high-pitched cackling ke ke ke..., with a tinkling quality that reminds some of the bleating of a goat
or the call of the Laughing Gull
.
The White-tailed Hawk is hard to confuse with any other bird, except that in the Southern Hemisphere
winter, young birds are sometimes mistaken for migrant Red-backed Hawks.
are known:
The White-tailed Hawk can be found anywhere from coastal
Texas
and the Rio Grande Valley
to central Argentina
as well as many Caribbean
islands, although mostly the southern ones. For habitat
it prefers open or semi-open regions up to 2,000 ft (c. 600 m) ASL
, with few trees to hinder its flight. It is not a migratory bird, though some populations may make regional movements when food is scarce. It likes to perch on bushes, trees, telephone poles or even stand around on the ground, as well as to soar
. Generally, it prefers arid
habitat and rarely occurs in very rainy locales.
Though it will disappear from unsuitable locations after habitat fragmentation
, it has a wide range and is not considered to be a globally threatened species
by the IUCN.
Its preferred hunting technique is to hover and observe the surroundings for signs of potential prey, gliding to another place when nothing is found. The diet of the White-tailed Hawk varies with its environment. Rabbit
s make up the majority of the hawk's diet in southern Texas, while lizard
s of 12 in (30 cm) in length and more are the preferred prey in the Dutch West Indies. Other animals such as cotton rat
s, snake
s, frog
s, arthropod
s (especially grasshopper
s, cicada
s and beetle
s), and smallish bird
s such as passerine
s or quail
s are also eaten; it will snatch chicken
s when no other source of food is available. In the open cerrado
of Brazil
, mixed-species feeding flock
s will react to a White-tailed Hawk with almost as much alarm as they do when seeing such dedicated predators of birds as the Aplomado Falcon
. The White-tailed Hawk is also known to feed on carrion
and to gather with other birds at brushfire
s to catch small animals fleeing the flames.
Breeding pairs of White-tailed Hawks build nests out of freshly broken twigs, often of thorn
y plants, 5–15 ft (1.5–5 m) or more above the ground on top of a tree or yucca
, preferably one growing in an elevated location giving good visibility from the nest. The nest's interior is cushioned it with dried grasses and other fine materials; green twigs of mesquite
or other aromatic plants are often placed in the nest too, perhaps to deter parasites. Like many Accipitridae
, White-tailed Hawks do not like to abandon a nest site, and nests built up over the years can thus reach sizes of up to three feet (1 m) across. The eggs are white, often lightly spotted with brown or lavender; between one and three (usually two) are laid per clutch
. When approached on the nest, the adults will get airborne and observe the intruder from above, unlike related hawks, which usually wait much longer to flush and then launch a determined attack.
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....
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...
found in tropical or subtropical environments across 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...
.
Description
Averaging 21–23 in (53–58 cm) in length with a wing span of around 4 ft (1.2 m), the super White-tailed Hawk is a large, stocky buteoButeo
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...
hawk
Hawk
The term hawk can be used in several ways:* In strict usage in Australia and Africa, to mean any of the species in the subfamily Accipitrinae, which comprises the genera Accipiter, Micronisus, Melierax, Urotriorchis and Megatriorchis. The large and widespread Accipiter genus includes goshawks,...
. Adult birds are grey above and white below and on the rump, with faint pale grey or rufous barring. The short tail is white with a narrow black band near the end that is conspicuous in flight. A rusty-red shoulder patch is just as characteristic when the bird is sitting with wings closed. The wings are dark above, admixed with grey near the bases of the blackish primary remiges. The underwing is whitish, with indistinct brownish barring on the underwing coverts that extends onto the flanks and thighs. The iris is hazel, 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...
is pale green, the beak
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
is black with a horn-colored base, and the feet are yellow with black talons.
Immature birds are somewhat darker than adults; they may appear nearly black in faint light, in particular individuals which have little white below. The wing lining is conspicuously spotted black-and-white; the rusty shoulder patch is absent in younger birds. The tail changes from brown with several dark bars to greyish with a hazy dark band as the birds approach maturity. The bare parts are colored much like in the adult.
Its call is a high-pitched cackling ke ke ke..., with a tinkling quality that reminds some of the bleating of a goat
Goat
The domestic goat is a subspecies of goat domesticated from the wild goat of southwest Asia and Eastern Europe. The goat is a member of the Bovidae family and is closely related to the sheep as both are in the goat-antelope subfamily Caprinae. There are over three hundred distinct breeds of...
or the call of the Laughing Gull
Laughing Gull
The Laughing Gull, Leucophaeus atricilla, is a medium-sized gull of North and South America. It breeds on the Atlantic coast of North America, the Caribbean, and northern South America. Northernmost populations migrate further south in winter, and this species occurs as a rare vagrant to western...
.
The White-tailed Hawk is hard to confuse with any other bird, except that in the Southern Hemisphere
Southern Hemisphere
The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...
winter, young birds are sometimes mistaken for migrant Red-backed Hawks.
Subspecies
Three subspeciesSubspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
are known:
- Buteo albicaudatus hypospodius – coastalWestern Gulf coastal grasslandsThe Western Gulf coastal grasslands are a subtropical grassland ecoregion of the southern United States and northeastern Mexico. It is known in Texas as "Coastal Prairie" and as the Tamaulipan pastizal in Mexico.-Setting:...
TexasTexasTexas 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...
and the Rio Grande ValleyRio Grande ValleyThe Rio Grande Valley or the Lower Rio Grande Valley, informally called The Valley, is an area located in the southernmost tip of South Texas...
through Middle AmericaMiddle America (Americas)Middle America is a region in the mid-latitudes of the Americas. In southern North America, it usually comprises Mexico, the nations of Central America, and the West Indies. The scope of the term may vary...
to northern ColombiaColombiaColombia, 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 western VenezuelaVenezuelaVenezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...
.
- Intermediate in size and coloration. No dark morph.
- Buteo albicaudatus colonus – Eastern Colombia to Surinam south to the mouth of the Amazon RiverAmazon RiverThe Amazon of South America is the second longest river in the world and by far the largest by waterflow with an average discharge greater than the next seven largest rivers combined...
, extending into the CaribbeanCaribbeanThe Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
.
- Buteo albicaudatus colonus – Eastern Colombia to Surinam south to the mouth of the Amazon River
- Small and pale. Dark morph is ashy grey all over, except for the tail and underwing coverts; sometimes extensively marked rufous on the underside. Dark-morph immatures are sometimes black all over, except for the tail.
- Buteo albicaudatus albicaudatus – Southern Amazon RainforestAmazon RainforestThe Amazon Rainforest , also known in English as Amazonia or the Amazon Jungle, is a moist broadleaf forest that covers most of the Amazon Basin of South America...
to central ArgentinaArgentinaArgentina , 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...
- Buteo albicaudatus albicaudatus – Southern Amazon Rainforest
- Large and dark; throat usually black (except in western Argentina). The dark morph appears blackish above, blackish-brown below.
Distribution and ecology
Western Gulf coastal grasslands
The Western Gulf coastal grasslands are a subtropical grassland ecoregion of the southern United States and northeastern Mexico. It is known in Texas as "Coastal Prairie" and as the Tamaulipan pastizal in Mexico.-Setting:...
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...
and the Rio Grande Valley
Rio Grande Valley
The Rio Grande Valley or the Lower Rio Grande Valley, informally called The Valley, is an area located in the southernmost tip of South Texas...
to central 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...
as well as many Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
islands, although mostly the southern ones. For habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
it prefers open or semi-open regions up to 2,000 ft (c. 600 m) 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...
, with few trees to hinder its flight. It is not a migratory bird, though some populations may make regional movements when food is scarce. It likes to perch on bushes, trees, telephone poles or even stand around on the ground, as well as to soar
Lift (soaring)
Gliding flight is heavier-than-air flight without the use of thrust. It is employed by gliding animals and by aircraft such as gliders. The most common human application of gliding flight is in sport and recreation using aircraft designed for this purpose...
. Generally, it prefers arid
Arid
A region is said to be arid when it is characterized by a severe lack of available water, to the extent of hindering or even preventing the growth and development of plant and animal life...
habitat and rarely occurs in very rainy locales.
Though it will disappear from unsuitable locations after habitat fragmentation
Habitat fragmentation
Habitat fragmentation as the name implies, describes the emergence of discontinuities in an organism's preferred environment , causing population fragmentation...
, it has a wide range and is not considered to be a globally threatened species
Threatened species
Threatened species are any speciesg animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future.The World Conservation Union is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories,...
by the IUCN.
Its preferred hunting technique is to hover and observe the surroundings for signs of potential prey, gliding to another place when nothing is found. The diet of the White-tailed Hawk varies with its environment. Rabbit
Rabbit
Rabbits are small mammals in the family Leporidae of the order Lagomorpha, found in several parts of the world...
s make up the majority of the hawk's diet in southern Texas, while 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 of 12 in (30 cm) in length and more are the preferred prey in the Dutch West Indies. Other animals such as cotton rat
Cotton rat
A cotton rat is any member of the rodent genus Sigmodon. They are called cotton rats because they build their nests out of cotton, and can damage cotton crops. Cotton rats have small ears and dark coats, and are found in North and South America....
s, snake
Snake
Snakes are elongate, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales...
s, 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, arthropod
Arthropod
An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...
s (especially grasshopper
Grasshopper
The grasshopper is an insect of the suborder Caelifera in the order Orthoptera. To distinguish it from bush crickets or katydids, it is sometimes referred to as the short-horned grasshopper...
s, cicada
Cicada
A cicada is an insect of the order Hemiptera, suborder Auchenorrhyncha , in the superfamily Cicadoidea, with large eyes wide apart on the head and usually transparent, well-veined wings. There are about 2,500 species of cicada around the world, and many of them remain unclassified...
s and beetle
Beetle
Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...
s), and smallish 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 such as passerine
Passerine
A passerine is a bird of the order Passeriformes, which includes more than half of all bird species. Sometimes known as perching birds or, less accurately, as songbirds, the passerines form one of the most diverse terrestrial vertebrate orders: with over 5,000 identified species, it has roughly...
s or 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...
s are also eaten; it will snatch chicken
Chicken
The chicken is a domesticated fowl, a subspecies of the Red Junglefowl. As one of the most common and widespread domestic animals, and with a population of more than 24 billion in 2003, there are more chickens in the world than any other species of bird...
s when no other source of food is available. In the open cerrado
Cerrado
The Cerrado, is a vast tropical savanna ecoregion of Brazil, particularly in the states of Gioas and Minas Gerais...
of 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...
, mixed-species feeding flock
Mixed-species feeding flock
A mixed-species feeding flock, also termed a mixed-species foraging flock, mixed hunting party or informally bird wave, is a flock of usually insectivorous birds of different species, that join each other and move together while foraging...
s will react to a White-tailed Hawk with almost as much alarm as they do when seeing such dedicated predators of birds as the Aplomado Falcon
Aplomado Falcon
The Aplomado Falcon, Falco femoralis, is a medium-sized falcon of the Americas. The species' largest contiguous range is in South America, but not in the deep interior Amazon Basin. It was long known as Falco fusco-coerulescens or Falco fuscocaerulescens, but these names are now believed to refer...
. The White-tailed Hawk is also known to feed on carrion
Carrion
Carrion refers to the carcass of a dead animal. Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters include vultures, hawks, eagles, hyenas, Virginia Opossum, Tasmanian Devils, coyotes, Komodo dragons, and burying beetles...
and to gather with other birds at brushfire
Brushfire
Brushfire may refer to:* Brushfire Records, a record label* Brushfire , a fictional supervillain* Brushfire Fairytales, an album by Jack Johnson* Brushfire Inc., an advertising agency in Cedar Knolls, NJ* Brush fire, a wild fire...
s to catch small animals fleeing the flames.
Breeding pairs of White-tailed Hawks build nests out of freshly broken twigs, often of thorn
Thorns, spines, and prickles
In botanical morphology, thorns, spines, and prickles are hard structures with sharp, or at least pointed, ends. In spite of this common feature, they differ in their growth and development on the plant; they are modified versions of different plant organs, stems, stipules, leaf veins, or hairs...
y plants, 5–15 ft (1.5–5 m) or more above the ground on top of a tree or yucca
Yucca
Yucca is a genus of perennial shrubs and trees in the family Asparagaceae, subfamily Agavoideae. Its 40-50 species are notable for their rosettes of evergreen, tough, sword-shaped leaves and large terminal panicles of white or whitish flowers. They are native to the hot and dry parts of North...
, preferably one growing in an elevated location giving good visibility from the nest. The nest's interior is cushioned it with dried grasses and other fine materials; green twigs of mesquite
Mesquite
Mesquite is a leguminous plant of the Prosopis genus found in northern Mexico through the Sonoran Desert and Chihuahuan Deserts, and up into the Southwestern United States as far north as southern Kansas, west to the Colorado Desert in California,and east to the eastern fifth of Texas, where...
or other aromatic plants are often placed in the nest too, perhaps to deter parasites. Like many 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...
, White-tailed Hawks do not like to abandon a nest site, and nests built up over the years can thus reach sizes of up to three feet (1 m) across. The eggs are white, often lightly spotted with brown or lavender; between one and three (usually two) are laid per 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...
. When approached on the nest, the adults will get airborne and observe the intruder from above, unlike related hawks, which usually wait much longer to flush and then launch a determined attack.