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Aug 27 2011

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Ayress Hawk-Eagle (Hieraaetus ayresii)

Ayress Hawk-Eagle

[order] ACCIPITRIFORMES | [family] Accipitridae | [latin] Hieraaetus ayresii | [authority] Gurney, 1862 | [UK] Ayress Hawk-Eagle | [FR] Aigle d’Ayres | [DE] Fleckenadler | [ES] Aguila-azor de Ayres | [NL] Ayres’ Havikarend

Subspecies

Monotypic species

Genus

Members of the genus Hieraaetus are small to medium-sized eagles, with long and pointed wings; a longish tail, and feathered legs. They are very active eagles, not given to eating carrion, and found usually in lightly forested country. The genus is difficult to separate from Aquila, Spizastur and Spizaetus. Some species have at one time or another been placed in more than one genus, and some references combine Hieraaetus with Aquila. The main species are: Hieraaetus fasciatus of southern Eurasia, the Booted Eagle Hieraaetus pennatus of Eurasia, Hieraaetus morphnoides of Australia and the New Guinea race – Hieraaetus morphnoides weiskei, the smallest of all the booted eagles; Hieraaetus dubius of Africa and Hieraaetus kienerii of India.

Physical charateristics

The adult male is sepia above, mottled with white, and usually with a white forehead and eyebrow. The upper-wing coverts are similar. The tail is ashy grey with a broad black tip and three to four narrower dark bars. Primary and secondary flight feathers are black. The underside is white, with heavy dark brown spots and blotches on the breast and belly, becoming fewer on thighs and vent. The legs are pure white. The under-wing coverts are brown mottled with white, the under side of flight feathers is dark, heavily barred and without a noticeable grey patch. The eyes are yellow to orange, the cere and feet yellow, the beak bluish horn coloured, paler towards the base, and with a black tip. Females are larger than males, darker and usually more heavily spotted below, with less white on the forehead and eyebrow. There is a melanistic phase, which is mostly black with white markings.


wingspan min.: 120 cm wingspan max.: 130 cm
size min.: 45 cm size max.: 61 cm
incubation min.: 43 days incubation max.: 48 days
fledging min.: 70 days fledging max.: 80 days
broods: 1   eggs min.: 1  
      eggs max.: 1  

Range

A relatively rare and little-known bird throughout its range. It frequents either open forest, often in mountains, the wetter and better-wooded savannahs, or river-edge forest strips. It is not often found in the densest rain forests or in open country. It may occasionally appear in more open country when making local movements, but a pair is usually resident close to their breeding site.Africa : widespread. Ayres?s hawk eagle has a patchy sub-Saharan distribution ranging from Sierra Leone east to Somalia, and south to northern Namibia and northeast South Africa.

Habitat

A relatively rare and little-known bird throughout its range. It frequents either open forest, often in mountains, the wetter and better-wooded savannahs, or river-edge forest strips. It is not often found in the densest rain forests or in open country. It may occasionally appear in more open country when making local movements, but a pair is usually resident close to their breeding site.

Reproduction

At the beginning of the breeding season the pair soar above the forest near their nest, close together, and with a good deal of calling. They make occasional stoops into the forest trees at high speed. They give the impression of being closely bonded to each other, and to the nest site, seldom far away from it at all times of the year, and inclined to display right through and outside the breeding season.
The nest is a bulky structure built in a fork of a forest tree, 30-60 feet above ground. It is made of thin sticks up to half an inch in diameter, and is fairly square and compact; about two-and-a-half feet across by one-and-a-half feet deep. Both sexes take part in nest repair, and spend much time at, and on, the nest in this period, which may involve months of occasional work, but usually occupies four to six weeks at the beginning of the breeding season. Green-leaved branches are brought at this time, in increasing quantities just prior to egg-laying.

Two eggs are generally laid – white, with odd markings of brown and lilac. They are laid in late winter. Replacement clutches rea sometimes laid at unusual times – when a natural disaster befalls a nest this species sometimes lays again up to three months later.
The female is a very close and tight sitter, and incubates alone. The male feeds her near the nest at intervals of two to three days. She does not leave the nest to kill for herself, but answers the male’s call and leaves the nest to receive prey from him. The male also visits during the incubation period without bringing prey, in which case the female usually leaves the nest and joins him, returning in a few minutes. The incubation period is 45 days.

Like other young eagles, the young when first hatched is helpless. The first body feathers break through the down by about 26 days, and cover it at 53 days; the crest has by then developed. Thereafter plumage development is largely in the wings and tail. The eaglet will try to feed it self at about 40 days, but is not usually successful until about 50 days. The young is rather sluggish, but towards the end of the fledging period practises wing-flapping, and climbs out on to the branches of the nest tree at times. It makes its first flight at about 75 days.
The female spends most of her time on the nest for the first ten days of the fledging period and thereafter the time on the nest is gradually reduced until, towards the end of the fledging period, she is only on the nest for brief periods amounting to about an hour during daylight. Right up to the end of the fledging period she roosts on the nest with the eaglet. The male’s job is to bring prey in the early fledging period; he does not feed the chick, although it will beg from him, and when he arrives with prey in the female’s absence he leaves quite quickly. The female feeds the eaglet in the early stages and up to 55 days on occasion; between 24 days and 40 days she spends most of the time perched on trees near the nest, but not brooding the eaglet. At this time she pulls off and brings to the nest green branches collected from trees within 100 yards or so of the nest. After 25 days she does kill some prey for the eaglet herself, and in the last third of the fledging period she brings as many kills as the male. In the early stages she shares the kills brought by the male with the eaglet.
After the eaglet has flown it remains near the nest for some time, roosting near it at night and some times in it, for a minimum of three weeks. The family of adults and eaglet remain near the nest for up to three months, and the eaglet becomes independent at about that time, the total nesting cycle from nest repair to family dispersal occupying about 230-240 days.

Feeding habits

The Ayres’ Hawk-eagle subsists on a diet composed mainly of small birds, from small passerines to doves, but occasionally larger. Apart from birds, it kills only an occasional squirrel. It occasionally attacks domestic poultry and pigeons. Birds are mainly caught on tree branches, but are occasionally taken in flight also.

Video Ayress Hawk-Eagle

httpv://www.youtube.com/watch?v=5nhGzpDlQdE

copyright: khaled Azamnoor


Conservation

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size may be small, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Ayress Hawk-Eagle status Least Concern

Migration

In the rainy season (Nov-Apr) moves out of denser and taller deciduous woodlands of C Africa into more open tree savanna further S, and probably into coastal E Africa; spring foliage turns woodland into forest and tree savanna into woodland. May then enter towns in S Africa to prey mainly on doves and feral pigeons. Similar N-S movements expected in W Africa, where species recorded (uncertainly) W to Senegambia.

Distribution map

Ayress Hawk-Eagle distribution range map

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