Buteo Temporal range: Oligocene – present | |
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Common buzzard (Buteo buteo) | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Accipitriformes |
Family: | Accipitridae |
Subfamily: | Buteoninae |
Genus: | Buteo Lacépède, 1799 |
Type species | |
Falco buteo Linnaeus, 1758 | |
Species | |
About 30, see text | |
Synonyms | |
Asturina |
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 the New World (Etymology: Buteo is the Latin name of the common buzzard [1] ). As both terms are ambiguous, buteo is sometimes used instead, for example, by the Peregrine Fund. [2]
Buteos are fairly large birds. Total length can vary from 30 to 75 cm (12 to 30 in) and wingspan can range from 67 to 170 cm (26 to 67 in). The lightest known species is the roadside hawk, [lower-alpha 1] at an average of 269 g (9.5 oz) although the lesser known white-rumped and Ridgway's hawks are similarly small in average wingspan around 75 cm (30 in), and average length around 35 cm (14 in) in standard measurements. The largest species in length and wingspan is the upland buzzard, which averages around 65 cm (26 in) in length and 152 cm (60 in) in wingspan. The upland is rivaled in weight and outsized in foot measurements and bill size by the ferruginous hawk. In both of these largest buteos, adults typically weigh over 1,200 g (2.6 lb), and in mature females, can exceed a mass of 2,000 g (4.4 lb). [5] [6] [7] [8] All buteos may be noted for their broad wings and sturdy builds. They frequently soar on thermals at midday over openings and are most frequently seen while doing this. The flight style varies based on the body type and wing shape and surface size. Some long-winged species, such as rough-legged buzzards and Swainson's hawks, have a floppy, buoyant flight style, while others, such as red-tailed hawks and rufous-tailed hawks, tend to be relatively shorter-winged, soaring more slowly and flying with more labored, deeper flaps. [5] Most small and some medium-sized species, from the roadside hawk to the red-shouldered hawk, often fly with an alternation of soaring and flapping, thus may be reminiscent of an Accipiter hawk in flight, but are still relatively larger-winged, shorter-tailed, and soar more extensively in open areas than Accipiter species do. [5] [9] Buteos inhabit a wide range of habitats across the world, but tend to prefer some access to both clearings, which provide ideal hunting grounds, and trees, which can provide nesting locations and security. [6] [7]
All Buteo species are to some extent opportunistic when it comes to hunting, and prey on almost any type of small animal as it becomes available to them. However, most have a strong preference for small mammals, mostly rodents. Rodents of almost every family in the world are somewhere preyed upon by Buteo species. [5] [6] [7] Since many rodents are primarily nocturnal, most buteos mainly hunt rodents that may be partially active during the day, which can include squirrels and chipmunks, voles, and gerbils. More nocturnal varieties are hunted opportunistically and may be caught in the first or last few hours of light. [5] [7] Other smallish mammals, such as shrews, moles, pikas, bats, and weasels, tend to be minor secondary prey, although can locally be significant for individual species. [5] [7] Larger mammals, such as rabbits, hares, and marmots, including even adult specimens weighing as much as 2 to 3 kg (4.4 to 6.6 lb), may be hunted by the heaviest and strongest species, such as ferruginous, [7] [10] [11] red-tailed [12] and white-tailed hawks. [13] Birds are taken occasionally, as well. Small to mid-sized birds, i.e. passerines, woodpeckers, waterfowl, pigeons, and gamebirds, are most often taken. However, since the adults of most smaller birds can successfully outmaneuver and evade buteos in flight, much avian prey is taken in the nestling or fledgling stages or adult birds if they are previously injured. [5] [7] An exception is the short-tailed hawk, which is a relatively small and agile species and is locally a small bird-hunting specialist. [14] The Hawaiian hawk, which evolved on an isolated group of islands with no terrestrial mammals, was also initially a bird specialist, although today it preys mainly on introduced rodents. Other prey may include snakes, lizards, frogs, salamanders, fish, and even various invertebrates, especially beetles. In several Buteo species found in more tropical regions, such as the roadside hawk or grey-lined hawk, reptiles and amphibians may come to locally dominate the diet. [5] Swainson's hawk, despite its somewhat large size, is something of exceptional insect-feeding specialist and may rely almost fully on crickets and dragonflies when wintering in southern South America. [15] [16] Carrion is eaten occasionally by most species, but is almost always secondary to live prey. [5] The importance of carrion in the Old World "buzzard" species is relatively higher since these often seem slower and less active predators than their equivalents in the Americas. [17] [18] [19] Most Buteo species seem to prefer to ambush prey by pouncing down to the ground directly from a perch. In a secondary approach, many spot prey from a great distance while soaring and circle down to the ground to snatch it. [5]
Buteos are typical accipitrids in most of their breeding behaviors. They all build their own nests, which are often constructed out of sticks and other materials they can carry. Nests are generally located in trees, which are generally selected based on large sizes and inaccessibility to climbing predators rather than by species. Most Buteos breed in stable pairs, which may mate for life or at least for several years even in migratory species in which pairs part ways during winter. Generally from 2 to 4 eggs are laid by the female and are mostly incubated by her, while the male mate provides food. Once the eggs hatch, the survival of the young is dependent upon how abundant appropriate food is and the security of the nesting location from potential nest predators and other (often human-induced) disturbances. As in many raptors, the nestlings hatch at intervals of a day or two and the older, strong siblings tend to have the best chances of survival, with the younger siblings often starving or being handled aggressively (and even killed) by their older siblings. The male generally does most of the hunting and the female broods, but the male may also do some brooding while the female hunts as well. Once the fledgling stage is reached, the female takes over much of the hunting. After a stage averaging a couple of weeks, the fledglings take the adults‘ increasing indifference to feeding them or occasional hostile behavior towards them as a cue to disperse on their own. Generally, young Buteos tend to disperse several miles away from their nesting grounds and wander for one to two years until they can court a mate and establish their own breeding range. [5] [6] [7]
The Buteo hawks include many of the most widely distributed, most common, and best-known raptors in the world. Examples include the red-tailed hawk of North America and the common buzzard of Eurasia. Most Northern Hemisphere species are at least partially migratory. In North America, species such as broad-winged hawks and Swainson's hawks are known for their huge numbers (often called "kettles") while passing over major migratory flyways in the fall. Up to tens of thousands of these Buteos can be seen each day during the peak of their migration. Any of the prior mentioned common Buteo species may have total populations that exceed a million individuals. [5] On the other hand, the Socotra buzzard and Galapagos hawks are considered vulnerable to extinction per the IUCN. The Ridgway's hawk is even more direly threatened and is considered Critically Endangered. These insular forms are threatened primarily by habitat destruction, prey reductions and poisoning. [5] [6] The latter reason is considered the main cause of a noted decline in the population of the more abundant Swainson's hawk, due to insecticides being used in southern South America, which the hawks ingest through crickets and then die from poisoning. [20]
The genus Buteo was erected by the French naturalist Bernard Germain de Lacépède in 1799 by tautonymy with the specific name of the common buzzard Falco buteo which had been introduced by Carl Linnaeus in 1758. [21] [22]
A number of fossil species have been discovered, mainly in North America. Some are placed here primarily based on considerations of biogeography, Buteo being somewhat hard to distinguish from Geranoaetus based on osteology alone: [52]
An unidentifiable accipitrid that occurred on Ibiza in the Late Pliocene/Early Pleistocene may also have been a Buteo. [57] If this is so, the bird can be expected to aid in untangling the complicated evolutionary history of the common buzzard group.
The prehistoric species "Aquila" danana, Buteogallus fragilis (Fragile eagle), and Spizaetus grinnelli were at one time also placed in Buteo. [52]
Buzzard is the common name of several species of birds of prey.
The rough-legged buzzard (Europe) or rough-legged hawk is a medium-large bird of prey. It is found in Arctic and Subarctic regions of North America, Europe, and Russia during the breeding season and migrates south for the winter. It was traditionally also known as the rough-legged falcon in such works as John James Audubon's The Birds of America.
The red-tailed hawk is a bird of prey that breeds throughout most of North America, from the interior of Alaska and northern Canada to as far south as Panama and the West Indies. It is one of the most common members within the genus of Buteo in North America or worldwide. The red-tailed hawk is one of three species colloquially known in the United States as the "chickenhawk", though it rarely preys on standard-sized chickens. The bird is sometimes also referred to as the red-tail for short, when the meaning is clear in context. Red-tailed hawks can acclimate to all the biomes within their range, occurring on the edges of non-ideal habitats such as dense forests and sandy deserts. The red-tailed hawk occupies a wide range of habitats and altitudes, including deserts, grasslands, coniferous and deciduous forests, agricultural fields, and urban areas. Its latitudinal limits fall around the tree line in the subarctic and it is absent from the high Arctic. Generally it favors varied habitats with open woodland, woodland edge and open terrain. It is legally protected in Canada, Mexico, and the United States by the Migratory Bird Treaty Act.
The ferruginous hawk is a large bird of prey and belongs to the broad-winged buteo hawks. An old colloquial name is ferrugineous rough-leg, due to its similarity to the closely related rough-legged hawk.
Accipiter is a genus of birds of prey in the family Accipitridae. With 49 recognized species it is the most diverse genus in its family. Most species are called goshawks or sparrowhawks, although with the exception of the American goshawk almost all New World species are simply known as "hawks". 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 procoracoid foramen and are also distinct as regards DNA sequence. They may warrant separation in the old genus Hieraspiza.
Harris's hawk, formerly known as the bay-winged hawk, dusky hawk, and sometimes a wolf hawk, and known in Latin America as peuco, is a medium-large bird of prey that breeds from the southwestern United States south to Chile, central Argentina, and Brazil. This bird is sometimes reported to be at large in Western Europe, especially Britain, but it is a popular species in falconry and these records almost invariably all refer to escapes from captivity.
The zone-tailed hawk is a medium-sized hawk of warm, dry parts of the Americas. It is somewhat similar in plumage and flight style to a common scavenger, the turkey vulture, and may benefit from being able to blend into groups of vultures. It feeds on small terrestrial tetrapods of all kinds.
Aquila is the genus of true eagles. The genus name is Latin for "eagle", possibly derived from aquilus, "dark in colour". It is often united with the sea eagles, buteos, and other more heavyset Accipitridae, but more recently they appear to be less distinct from the slenderer accipitrine hawks than previously believed. Eagles are not a natural group but denote essentially any bird of prey large enough to hunt sizeable vertebrate prey.
The white-tailed hawk is a large bird of prey species found in tropical and subtropical environments of the Americas.
The black-chested buzzard-eagle is a bird of prey of the hawk and eagle family (Accipitridae). It lives in open regions of South America. This species is also known as the black buzzard-eagle, the gray buzzard-eagle, or analogously with "eagle" or "eagle-buzzard" replacing "buzzard-eagle", or as the Chilean blue eagle. It is sometimes placed in the genus Buteo.
The jackal buzzard is a fairly large African bird of prey. The taxonomy of this species has caused some confusion in the past and it almost certainly belongs in a species complex with other African Buteo species. Some taxonomists have considered this species, the Archer's buzzard, and the augur buzzard to be the same superspecies. Many taxonomists consider them all to be distinct, having different calls, different home ranges and variations in plumage. This is a species that lives among mountains, and on adjacent savanna and grassland. It is resident and non-migratory throughout its range.
The augur buzzard is a fairly large African bird of prey. This species is distinct in typical adult plumage for its blackish back, whitish underside and orange-red tail, while juvenile augur buzzards are generally rather brown in colour; however a dark morph is known, which causes the bird's entire body to become darker. This member of the Buteo genus is distributed in several parts of the central and southern Africa, normally being found from Ethiopia to southern Angola and central Namibia. It is resident and non-migratory throughout its range. This is a species of mountains, and adjacent savannah and grassland. This is a typical buteonine raptor, being a generalist predator which tends to prefer small mammals supplemented by reptiles and birds among various prey items.
The mountain buzzard is a bird of prey that lives in montane forests in East Africa, it and the forest buzzard of southern Africa were, until recently, considered to be a single species.
Buteogallus is a genus of birds of prey in the family Accipitridae. All members of this genus are essentially neotropical, but the distribution of a single species extends slightly into the extreme southwestern United States. Many of the species are fond of large crustaceans and even patrol long stretches of shore or riverbank on foot where such prey abounds, but some have a rather different lifestyle. Unlike many other genera of raptor, some members are referred to as "hawks", and others as "eagles".
The black-and-white hawk-eagle is a bird of prey species in the eagle and hawk family (Accipitridae). It is found throughout a large part of tropical America, from southern Mexico to northern Argentina.
The variable hawk is a polymorphic species of bird of prey in the family Accipitridae.
The gray hawk or Mexican goshawk is a smallish raptor found in open country and forest edges. It is sometimes placed in the genus Asturina as Asturina plagiata. The species was split by the American Ornithological Society (AOU) from the gray-lined hawk. The gray hawk is found from Costa Rica north into the southwestern United States.
The red-shouldered hawk is a medium-sized buteo. Its breeding range spans eastern North America and along the coast of California and northern to northeastern-central Mexico. It is a permanent resident throughout most of its range, though northern birds do migrate, mostly to central Mexico. The main conservation threat to the widespread species is deforestation.
The short-tailed hawk is an American bird of prey in the family Accipitridae, which also includes the eagles and Old World vultures. As a member of the genus Buteo, it is not a true hawk and thus also referred to as a "buteo" or "buzzard". The white-throated hawk is a close relative and was formerly included in the species B. brachyurus.
Swainson's hawk is a large bird species in the Accipitriformes order. This species was named after William Swainson, a British naturalist. It is colloquially known as the grasshopper hawk or locust hawk, as it is very fond of Acrididae and will voraciously eat these insects whenever they are available.