Chilean hawk | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Accipitriformes |
Family: | Accipitridae |
Genus: | Astur |
Species: | A. chilensis |
Binomial name | |
Astur chilensis | |
Synonyms | |
Accipiter bicolor chilensisPhilippi & Landbeck, 1864 (but see text) Contents |
The Chilean hawk (Astur chilensis) is a bird of prey species belonging to the family Accipitridae. It breeds in Andes forests from central Chile and western Argentina south to Tierra del Fuego, from sea level to 2,700 m[ verification needed ] altitude (though birds are rarely observed above 1,000 m). Some winter apparently in the lowlands of NW Argentina.
It is sometimes considered to be a subspecies of its northern relative the bicolored hawk (Astur bicolor), including by the American Ornithological Society and sometimes a distinct species. The two show differences in habitat preference and have allopatric distributions. But the situation is complicated by the subspecies pileatus, which is intermediate in plumage between bicolor and chilensis, and has been variously assigned to either species by those that consider them distinct.
The male is 37 to 38 cm long, while the larger female measures 41 to 42 cm. The adults have black upperparts, and an ash-grey chest and abdomen with dark barring. The throat has longitudinal dark stripes and the undertail is white. The uppertail is brown with 5 or 6 dark bands. The legs are greenish yellow, and the eyes are yellow. The sexes have similar plumage.
Young birds have browner upperparts with cream fringes to the feathers. The paler chest and abdomen have longitudinal stripes. The paler uppertail makes the banding more obvious.
Birds are only vocal during the breeding season. While engaging in reproductive activity, its calls do not seem to differ from those of the bicoloured hawk. This has at least two rather high-pitched scolding vocalizations: a barking row of keh or kow, and a woodpecker-like faster and accelerating staccato of kek calls. These are given near the nest and might announce intruders such as the scientists coming to study the birds. A series of higher-pitched kie, given by a definite Chilean hawk under similar circumstances, might replace one of the above, or it might be a distinct type of call. Pairmates address each other with a squealing waaah, and a soft clear whistle is apparently used by parents to communicate something to the young. [1]
In Argentina, it is found north to Neuquén Province at about 36° latitude. The northern limit of the breeding range in Chile is not well known. In significant numbers, the Chilean hawk probably only occurs north to O'Higgins Region, though it at least occasionally breeds in Valparaíso Region, and perhaps also in Coquimbo Region and Fray Jorge National Park from where there are a few sightings. The southern limit is generally accepted to be at about 55° latitude in Tierra del Fuego. [1]
Their movement patterns are not well resolved. Generally it seems to be sedentary, but there is a seasonal influx of Chilean hawks to NW Argentina. Perhaps they follow the swarms of migrant passerines or even Chilean pigeons (Columba araucana). It has been recorded as breeding in Magallanes Province but migrating away afterwards. Young birds seem to be quite prone to vagrancy: there is one certain and one possible record from Tafí del Valle and Oasis de Pica, respectively; both locations are hundreds of kilometers north even of the suspected breeding range. [1]
The Chilean hawk is specifically found in temperate forest. Far more rarely, it is also found in sclerophyllous forest, parkland and mixed forest and open habitat. Top hunt, it also visits open areas like shrubland, grassland or agricultural land to hunt. It is rarely if ever seen in heavily human-modified habitat however, and the few individuals that have been encountered in city parks and gardens are probably not resident birds. As it seems, it requires not much less than 200 hectares of native forest to breed. [1]
Typically, forest inhabited by this bird is dominated by Araucaria and southern beech (Nothofagus). Particular species that have been recorded are coihue (N. dombeyi), hualle (N. obliqua) and lenga (N. pumilio). It probably tolerates some logging, as long as the native character of the forest is not altered. Secondary growth with abundant mature trees remaining and dense undergrowth, e.g. of South American mountain bamboo (Chusquea), as caused by limited logging activity, may even be prime breeding habitat, although too little is known to be certain. When enough native forest is present, plantations, e.g. of introduced pines, are also utilized. [1]
During the day, it likes to perch on branches in its territory, moving between favorite areas of forest in low flight. Areas with strong human activity like settlements are approached cautiously; it is generally not a bird that announces its presence. Pairs split outside the breeding season; it is not studied whether they are monogamous only during the breeding season or for several seasons. It seldom soars unrelated to reproductive activity. Males do aerobatic displays in courtship, such as a double loop resembling an upright "8". [1]
The louse Colpocephalum turbinatum was found on a museum specimen of the Chilean hawk, but whether it actually parasitizes these birds or had simply crossed over from some other specimen is not known. [1]
It is not well known how this carnivore catches its prey, but as it seems it is optimized for pursuit of small and maneuvrable birds throughout all levels of the forest. It is also able to seize large insects in mid-air. Both active searching for prey and sitting in ambush to wait what might come along has been observed. During the breeding season, pairs may cooperate in hunting; their different sizes ensures that they do not compete for prey much. [1]
The Chilean hawk's food is almost exclusively birds (97.8% of all prey remains in one study), [2] in particular a diverse selection of forest passerines. More than 30 bird species are documented to be eaten by this hawk at least occasionally. Rodents of at least 4 species and every now and then an occasional insect or squamate round off its diet. [1]
The Chilean hawk hunts forest passerines quite indiscriminately of species, habitat or habits provided they have the right size, though it has a preference for species that live closer to the forest floor. Depending on availability, favorite prey species include thorn-tailed rayadito (Aphrastura spinicauda) black-chinned siskin (Carduelis barbata), white-crested elaenia (Elaenia albiceps), Austral thrush (Turdus falcklandii) and fire-eyed diucon (Xolmis pyrope). [2] It has been claimed that the Chilean pigeon (Columba araucana) constitutes important prey, but this seems only to be correct at certain times or places, if at all.
This hawk breeds in the austral summer. Pairs apparently form from mid-late October on. Incubating birds have been observed in December, and chicks are seen from about New Year's Eve to February, after which the families disperse again. A 1937 nest and a 1945 egg description of the Chilean hawk appear to be based on a misidentification; the nest at least was probably of the chimango caracara (Milvago chimango). [1]
The oval platform nest measures about 50–80 by 50–60 cm and is some 25 cm high when freshly built. Some nests are more than twice as high; these might have been used in several years. It is built from strongly intertwined dry twigs and sticks. It is placed on forked branches in the upper part of a tree, close to the main trunk or a main vertical branch, some 16–20 m above ground. At least locally, full-grown coihue trees (Nothofagus dombeyi) seem to be much preferred for nesting. Nests are sometimes reused in successive seasons, but more often a new nest is constructed in a different tree every season. [3]
The clutch is probably two, sometimes three and rarely one, as usual for Accipitridae. The eggs are dull light bluish to off-white all over and are shaped like a chicken's egg. The eggshell's inside has a slightly more pronounced bluish tinge. Incubation lasts probably about 3 weeks. The parents defend their nesting grounds against other birds of prey, such as the red-backed hawk (Buteo polyosoma), and the golden eagle (Aquila chrysaetos); during approaches by such potentially dangerous species, the nestlings will tuck away their heads. It seems that 2 or 3 young are raised on a regular basis, unlike in many other Accipitridae where only the strongest nestling survives. [3]
Because of its forest habitat and secretive behaviour, the Chilean hawk is one of the least-studied raptors in the Patagonian temperate forest. It is considered relatively common in the Cape Horn region, e.g. in Ñuble National Reserve, population densities as high as 4 birds per square km have been recorded. Elsewhere, it is far less often seen and usually quite rare. Attempts to assess its population density are hampered by the fact that it requires a certain amount of prime habitat to settle in a locale at all. Thus, much otherwise suitable land might be under-utilized by these birds, and subpopulations have an extremely patchy distribution. [1]
It is listed as a rare or insufficiently known species in Chile and legally protected under the Hunting Law. In Argentina it is not listed as threatened. On a global scale, it is a rare bird, though not under immediate threat. Populations may decline due to increasing habitat loss from extensive fires, logging pressures, and hunting. [2] It is not evaluated by the IUCN, as they do not consider it specifically distinct, but is included on the CITES Appendix II as part of the blanket listing of Falconiformes. [1]
The Accipitridae is one of the three families within the order Accipitriformes, and is a family of small to large birds of prey 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 few feeding on fruit. The Accipitridae have a cosmopolitan distribution, being found on all the world's continents and a number of oceanic island groups. Some species are migratory. The family contains 255 species which are divided into 70 genera.
The Eurasian sparrowhawk, also known as the northern sparrowhawk or simply the sparrowhawk, is a small bird of prey in the family Accipitridae. Adult male Eurasian sparrowhawks have bluish grey upperparts and orange-barred underparts; females and juveniles are brown above with brown barring below. The female is up to 25% larger than the male – one of the greatest size differences between the sexes in any bird species. Though it is a predator which specialises in catching woodland birds, the Eurasian sparrowhawk can be found in any habitat and often hunts garden birds in towns and cities. Males tend to take smaller birds, including tits, finches and sparrows; females catch primarily thrushes and starlings but are capable of killing birds weighing 500 g (18 oz) or more.
Cooper's hawk is a medium-sized hawk native to the North American continent and found from southern Canada to Mexico. This species is a member of the genus Astur. As in many birds of prey, the male is smaller than the female. The birds found east of the Mississippi River tend to be larger on average than the birds found to the west. It is easily confused with the smaller but similar sharp-shinned hawk.
The shikra is a small bird of prey in the family Accipitridae found widely distributed in Asia and Africa where it is also called the little banded goshawk. The African forms may represent a separate species but have usually been considered as subspecies of the shikra. The shikra is very similar in appearance, as well as behavior, at least to some degree, to other species including the Chinese sparrowhawk, Eurasian goshawk and Eurasian sparrowhawk. They have a sharp two note call and have the typical flap and glide flight. Their calls are imitated by drongos and the common hawk-cuckoo resembles it in plumage. This species was formerly placed in the genus Accipiter.
The lizard buzzard, or lizard hawk, is a bird of prey in the family Accipitridae. It is native to Sub-Saharan Africa. Despite its name, it may be more closely related to the Accipiter hawks than the Buteo buzzards.
The Magellanic woodpecker is a species of large woodpecker found in southern Chile and southwestern Argentina; it is resident within its range. This species is the southernmost example of the genus Campephilus, which includes the famous ivory-billed woodpecker.
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 Japanese sparrowhawk is a bird of prey in the family Accipitridae which also includes many other diurnal raptors such as eagles, buzzards and harriers. The bird is known by many alternative names such as the Japanese lesser, Asiatic, or Eastern sparrowhawk. This species is a small raptor with broader and rounder wings and a shorter tail. Its total length measures 23–30 centimetres (9.1–11.8 in). It has a dark back and whitish underside with brown-grey barring and red-brown colouring on the sides in males, and with heavier brown barring on the abdomen in females. Both sexes have a stripe across the throat, but its more obvious in the female. Is it typically identified by its appearance, but occasionally produces a chattering kiki-kik-kik... sound. This species generally breeds in parts of Russia, Korea, Japan, and China. There are three subspecies of Japanese sparrowhawk that differ by distribution and appearance. The species is globally listed as least concern, although it is listed as endangered in Japan and protected in China.
The Réunion harrier, also known as Réunion marsh harrier, is a species of bird of prey belonging to the marsh harrier group of harriers. It is now found only on the Indian Ocean island of Réunion, although fossil material from Mauritius has been referred to this species. It is known locally as the papangue or pied jaune. The Malagasy harrier of Madagascar and the Comoro Islands was previously treated as a subspecies of this bird but is increasingly regarded as a separate species. The Réunion harrier appears to be declining in numbers and it is classed as an endangered species.
The bicolored hawk is a species of bird of prey in the family Accipitridae. It is found in forest, woodland, second growth, plantations, and wooded savanna in southeastern Mexico, Central America, and northern and central South America. Though generally uncommon, it is the most common species of Astur in most of its range, but it does not occur at altitudes above 2,700 metres (8,900 ft) such as the highest parts of the Andes.
Gundlach's hawk is a species of bird of prey in the family Accipitridae. It is one of 21 endemic bird species of Cuba. The common name and Latin binomial commemorate the German-Cuban ornithologist Juan Cristobal Gundlach (1810–1896). It is threatened by habitat loss and human persecution.
Henst's goshawk is a species of bird of prey in the family Accipitridae. It is a large, diurnal bird endemic to the island of Madagascar. It is an obligate forest species that occurs at very low densities on the island and is rarely seen. It can only occupy the primary and secondary forests found within the island. Its natural habitats are subtropical or tropical dry forest, subtropical or tropical moist lowland forest, subtropical or tropical moist montane forest, and plantations.
The black sparrowhawk, sometimes known as the black goshawk or great sparrowhawk, is the largest species of True hawk in Africa. It occurs mainly in forest and non-desert areas south of the Sahara, particularly where there are large trees suitable for nesting; favored habitat includes suburban and human-altered landscapes. It preys predominantly on birds of moderate size, such as pigeons and doves, in suburban areas.
The grey-bellied hawk or grey-bellied goshawk is a fairly large and rare species of forest-dwelling South American bird of prey in the family Accipitridae.
The rufous-tailed hawk is a species of bird of prey in the family Accipitridae.
Cassin's hawk-eagle or Cassin's eagle, is a relatively small eagle in the family Accipitridae. Its feathered legs mark it as member of the Aquilinae or booted eagle subfamily. A forest-dependent species, it occurs in primary rainforests across western, central and (marginally) eastern Africa where it preys on birds and tree squirrels. It was named after John Cassin who first described it in 1865. Due to widespread habitat destruction, its populations are steadily declining but have not yet warranted upgrading its status from Least Concern.
The Aquilinae are a subfamily of eagles of the family Accipitridae. The general common name used for members of this subfamily is "booted eagle", although this is also the common name of a member of the subfamily. At one point, this subfamily was considered inclusive with the Buteoninae based probably on some shared morphological characteristics. However, research on the DNA of the booted eagles has shown that they are a monophyletic group that probably have had millions of years of separation from other extant forms of accipitrid.
The Eurasian goshawk is a species of medium-large bird of prey in the family Accipitridae, a family which also includes other extant diurnal raptors, such as eagles, buzzards and harriers. It was formerly placed in the genus Accipiter. It is a widespread species that inhabits many of the temperate parts of the Eurasia. Except in a small portion of southern Asia, it is the only species of "goshawk" in its range and it is thus often referred to, both officially and unofficially, as simply the "goshawk". It is mainly resident, but birds from colder regions migrate south for the winter. As of 2023, the goshawks found primarily in North America are no longer considered Astur gentilis, but are now designated as the American goshawk.
The American goshawk is a species of raptor in the family Accipitridae. It was first described by Alexander Wilson in 1812. The American goshawk was previously considered conspecific with the Eurasian goshawk, but was assigned to a separate species in 2023 based on differences in morphology, vocalizations, and genetic divergence. It was formerly placed in the genus Accipiter. It is mainly resident, but birds from colder regions migrate south for the winter. In North America, migratory goshawks are often seen migrating south along mountain ridge tops at nearly any time of the fall depending on latitude.
Astur is a genus containing hawks, goshawks and sparrowhawk in the family Accipitridae. The species were formerly placed in the genus Accipiter.