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Rufous-thighed hawk | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Accipitriformes |
Family: | Accipitridae |
Genus: | Accipiter |
Species: | A. erythronemius |
Binomial name | |
Accipiter erythronemius (Kaup, 1850) | |
Synonyms | |
Accipiter striatus erythronemius |
The rufous-thighed hawk (Accipiter erythronemius) is a small hawk found from southern Brazil and southeastern Bolivia to Paraguay, Uruguay and northern Argentina. It is usually considered a subspecies of the sharp-shinned hawk by most taxonomists, including the American Ornithological Society, but the taxonomy is far from resolved, with some authorities considering the southern taxa to represent three separate species: white-breasted hawk (A. chionogaster), plain-breasted hawk (A. ventralis), and rufous-thighed hawk (A. erythronemius).
The breeding ranges of the rufous-thighed and sharp-shinned hawk is entirely allopatric. This allopatry combined with differences in plumage (see appearance) and, apparently, certain measurements, has been the background for the split, but hard scientific data are presently lacking (AOU).
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This is a small Accipiter hawk, with males 23 to 30 cm (9.1 to 11.8 in) long, with a wingspan of 42 to 58 cm (17 to 23 in) and weight from 82–115 g (2.9–4.1 oz). As common in Accipiter hawks, females are distinctly larger in size, averaging some 30% longer, and with a weight advantage of more than 50% being common. The female measures 29 to 37 cm (11 to 15 in) in length, has a wingspan of 58 to 68 cm (23 to 27 in) and weighs 150 to 219 g (5.3 to 7.7 oz). The wings measure 14.1–22.9 cm (5.6–9.0 in) each, the tail is 12–19 cm (4.7–7.5 in) long and the tarsus is 4.5–5.9 cm (1.8–2.3 in). Measurements given here are for the sharp-shinned hawk, but they are comparable for the remaining species. [1] Adults have short broad wings and a medium-length tail banded in blackish and gray with the tip varying among individuals from slightly notched through square to slightly rounded (often narrowly tipped white). The remiges (typically only visible in flight) are whitish barred blackish. The legs are long and very slender (hence the common name) and yellow. The hooked bill is black and the cere is yellowish.
The rufous-thighed hawk resembles the sharp-shinned hawk, but upperparts are darker, streaking to underparts rufous or dusky, cheeks are typically with a clear rufous patch (occasionally lacking almost entirely) and iris is yellow (contra illustrations in some books). Juveniles resemble juveniles of sharp-shinneds, but streaking to the underparts are typically restricted to throat and central underparts, with flanks scaled or barred (often also the belly).
The species is found in Uruguay, Paraguay, north-eastern Argentina and south-eastern Bolivia. It is, as far as known, resident in some regions and migratory in others. The movements are generally poorly understood, but it only occurs seasonally at some localities in Argentina. The rufous-thighed hawk is found in tropical and subtropical regions; both in lowlands and highlands.
These birds surprise and capture most of their prey from cover or while flying quickly through dense vegetation. They are adept at navigating dense thickets, although this hunting method is often hazardous to the hawk. The great majority of this hawk's prey are small birds, especially various songbirds such as sparrows, wood-warblers, finches, wrens, nuthatches, tits, icterids and thrushes. Typically, males will target smaller birds, such as sparrows and wood-warblers, and females will pursue larger prey, such as thrushes and flickers, leading to a lack of conflict between the sexes for prey. They often pluck the feathers off their prey on a post or other perch. Rarely, rufous-thighed hawks will also eat rodents, lizards, frogs, snakes, and large insects.
Rufous-thighed hawks construct a stick nest. Clutches of 3 to 8 eggs have been recorded, but 4 to 5 eggs is the typical clutch size. The eggs measure 37.6 mm × 30 mm (1.48 in × 1.18 in) and weigh about 19 g (0.67 oz). The incubation period is thought to average at about 30 days. After hatching, the young are brooded for 16 to 23 days by the female, while the male defends the territory and catches prey. The young fledge at the age of about a month and rely on their parents for feeding and protection another four weeks. The breeding behavior of the rufous-thighed hawk is comparably poorly known, but based on the available knowledge they appear to differ little from that of sharp-shinned hawks.
The rufous-thighed hawk is fairly common (but easily overlooked due to their secretive behavior) and presently considered safe.
The merlin is a small species of falcon from the Northern Hemisphere, with numerous subspecies throughout North America and Eurasia. A bird of prey once known colloquially as a pigeon hawk in North America, the merlin breeds in the northern Holarctic; some migrate to subtropical and northern tropical regions in winter. Males typically have wingspans of 53–58 centimetres (21–23 in), with females being slightly larger. They are swift fliers and skilled hunters which specialize in preying on small birds in the size range of sparrows to quail. The merlin has for centuries been well regarded as a falconry bird. In recent decades merlin populations in North America have been significantly increasing, with some merlins becoming so well adapted to city life that they forgo migration.
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.
The sharp-shinned hawk or Northern sharp-shinned hawk, commonly known as a sharpie, is a small hawk, with males being the smallest hawks in the United States and Canada, but with the species averaging larger than some Neotropical species, such as the tiny hawk. The taxonomy is far from resolved, with some authorities considering the southern taxa to represent three separate species: white-breasted hawk, plain-breasted hawk, and rufous-thighed hawk. The American Ornithological Society keeps all four variations conspecific.
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 Accipiter, sometimes referred to as true hawks, which are famously agile, relatively small hawks common to wooded habitats around the world and also the most diverse of all diurnal raptor genera. 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 Levant sparrowhawk is a small bird of prey. It measures 32–38 cm (13–15 in) in length with a wingspan of 65–75 cm (26–30 in). The female is larger than the male, but the difference is not as marked as with Eurasian sparrowhawk. The adult male is blue-grey above, with dark wingtips, and barred reddish below.
The pearl kite is a very small raptor found in open savanna habitat adjacent to deciduous woodland. It is the only member of the genus Gampsonyx. The scientific name commemorates the English naturalist William Swainson.
The savanna hawk is a large raptor found in open savanna and swamp edges. It was formerly placed in the genus Heterospizias. It breeds from Panama and Trinidad south to Bolivia, Uruguay and central Argentina. There are also reports of it in California, from 1973 in Alameda County and from 1974 in San Diego County.
The gray-headed kite is a raptor found in open woodland and swamp forests. It shares the genus Leptodon with the extremely rare white-collared kite. It breeds from eastern Mexico and Trinidad south to Peru, Bolivia, Brazil and northern Argentina.
The tiny hawk is a small diurnal bird of prey found in or near forests, primarily humid, throughout much of the Neotropics. It is primarily a bird-eater, and is known to prey on hummingbirds.
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 Accipiter 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.
The chestnut-flanked sparrowhawk is a small west African species of sparrowhawk in the family Accipitridae.
The red-thighed sparrowhawk, alternatively known as the red-legged sparrowhawk or western little sparrowhawk, is a species of sparrowhawk in the family Accipitridae from western and northern central Africa.
The Madagascar sparrowhawk is a species of bird of prey in the family Accipitridae.
The little sparrowhawk is a species of Afrotropical bird of prey in the family Accipitridae. It is the smallest member of the genus Accipiter and forms a superspecies with the red-thighed sparrowhawk.
The rufous-breasted sparrowhawk, also known as the rufous-chested sparrowhawk and as the red-breasted sparrowhawk, is a species of bird of prey in the family Accipitridae. It is found in Angola, Democratic Republic of the Congo, Eritrea, Eswatini, Ethiopia, Kenya, Lesotho, Malawi, Mozambique, Rwanda, South Africa, South Sudan, Tanzania, Uganda, Zambia, and Zimbabwe.
The African goshawk is an African species of bird of prey in the genus Accipiter which is the type genus of the family Accipitridae.
Ayres's hawk-eagle, also referred to as Ayres' eagle, is a medium-sized bird of prey in the family Accipitridae. It is native to African woodlands. Its name honors South African ornithologist Thomas Ayres.
The red-chested goshawk is a medium-size hawk of West Africa. It is often considered conspecific with the African goshawk.
The plain-breasted hawk is a small hawk described from Venezuela to western Bolivia. It is usually considered a subspecies of the sharp-shinned hawk by most taxonomists, including the American Ornithological Society, but the taxonomy is far from resolved, with some authorities considering the southern taxa to represent three separate species: white-breasted hawk, plain-breasted hawk, and rufous-thighed hawk.
The white-breasted hawk is a small hawk found from southern Mexico to Nicaragua. It is usually considered a subspecies of the sharp-shinned hawk by most taxonomists, including the American Ornithological Society, but the taxonomy is far from resolved, with some authorities considering the southern taxa to represent three separate species: white-breasted hawk, plain-breasted hawk, and rufous-thighed hawk.