Socotra Buzzard

Socotra Buzzard

Summary:

Profile Socotra Buzzard
[Authority] Porter and Kirwan, 2010 | [group] Kites, hawks and eagles | [order] ACCIPITRIFORMES | [family] Accipitridae | [latin] Buteo socotraensis | [UK] Socotra

[Authority] Porter and Kirwan, 2010 | [group] Kites, hawks and eagles | [order] ACCIPITRIFORMES | [family] Accipitridae | [latin] Buteo socotraensis | [UK] Socotra Buzzard | [FR] Buse de socotra | [DE] Socotrabussard | [ES] Busardo de socotra | [NL] Socotra Buizerd | copyright picture

Small to mid-sized,with relatively short,compact wings pale greyish, often with a gingery hue, and
10-12 narrow, dark bands; subterminal broadest + no pale horseshoe usually solid and dark brown,
contrasting rather strongly with the coverts, but less so than in B. rufinus. Brown upperparts and pale underparts, which are barred and blotched brown on the breast, belly and underwing-coverts. Individual plumage variation in both adult and juvenile plumages is less than in any of the other members of the B. buteo superspecies, as might be expected in an insular taxon. In adult plumage the brown upperparts are relieved only by pale bases to the outer primaries, which form a diffuse but noticeable panel. The uppertail is narrowly barred as it is in most B. b. buteo and some B. b. vulpinus. In socotraensis, nevertheless, the pale greyish tail, often showing a gingery hue, especially distally, has 10-12 narrow, dark bands, with the subterminal the broadest. Below socotraensis is white (very slightly tinged buff) with fine brown streaking on throat and heavier dark brown streaking on the breast, belly, flanks and thighs, becoming most solid. The warm brown
/ chestnut-brown underwing-coverts in socotraensis are rather irregularly streaked and chequered dark brown, most intensely on the greater coverts. The large carpal patch is solid dark brown. The variation in the strength or intensity of these underbody and underwingcovert markings is slight (Figs. 7-8). Some individuals possess a whiter throat, upper breast and thighs. The underside of the primaries and secondaries is similar to that of the other Buteo taxa, showing a wide dark band on the hindwing typical of adults.

Socotra Buzzard is resident in the foothills and plateaux, mostly where there are deep ravines, from sea level to at least 1,370 m, but principally at 150-800 m. It does not appear to be dependent on trees, but steep cliffs would seem to be prerequisite for nesting. No seasonal altitudinal movements have been observed, and it is reasonable to assume that if there are any, they are not significant. Competition for nesting sites has not been studied, but with Egyptian Vulture Neophron percnopterus, Peregrine Falcon Falco peregrinus and Brown-necked Raven Corvus ruficollis all using similar cliffledges for nesting on Socotra, this might be a limiting factor to the buzzard population. Much time is spent perched on rocks, cliff ledges, trees and bushes, which are presumably used as scanning posts to search for food. In all months, birds have been observed soaring high above plains and hills, sometimes in loose groups of up to five, often with spells of calling.

Diet almost certainly exclusively comprises reptiles and invertebrates. Individuals are often seen perched on a prominent rock or tree, and the method of foraging appears to be to wait for prey to come into range and then pounce. However, there is no detailed information on the diet of either adults or juveniles, but food being taken and consumed has included a snake, small lizard, locusts, at least once a large centipede and a large caterpillar. House Mouse Mus musculus and Black Rat Rattus rattus, both of which are found near settlements, where this buzzard rarely occurs. As the rodents are thought to be historically recent arrivals on the island, it has been assumed that the bulk of the buzzard?s prey must be lizards, large insects and possibly nestlings; the birds have
never been observed feeding on carrion. Clarification of its diet will be an important factor in guaranteeing its survival.


This species qualifies as Vulnerable because its population is estimated to be very small, although there is no evidence of a decline in the population, nor is there evidence of any serious and immediate threats, thus it is suspected to be stable [conservation status from birdlife.org]


Display, notably aerial tumbling and talon grappling, has been observed in October-December and February, and copulation in November. Nest building has been observed in late October and a nest with a chick (c.15 days old), being tended by both adults, was found on 28 October; in this case egg laying would have been in mid September. A nest with two eggs was found on 16 November and nests with young observed in January (young c.1 month old) and in early April, to which adults were bringing food. A juvenile in captivity on 2 March was just a few weeks out of the nest, suggesting egg laying in January. One instance of a pair nest building in April and May was not followed by egg
laying. Fully-fledged young, still with a strong parental bond, have been observed from mid February to early April. All the above observations suggest that the breeding season extends from September-April, with egg laying in September-January. It is probably important for this buzzard to have completed its breeding cycle before the onset of the monsoon winds in late May, which could hamper its ability to hunt and find food for the young. Broods of only one or two nestlings have been recorded on single occasions, but there is one record of a pair with three fledged young, indicating that clutch size can be larger. The few nests observed have been constructed of sticks on a cliff-ledge or crevice, sometimes with a tree, small bush or vegetation for protection or support.
Live branches with leaves have been observed being brought to the nest. No tree nests have been reported. Nests have been noted at 150-650 m. There is no information on the role of the sexes in nest building or incubation, both have been observed tending young in the nest and are present during the post-fledging period. There is a record of repeated attacks on an Egyptian Vulture by a pair of buzzards, when their nest was approached, and another observer reported an adult becoming agitated by a Peregrine Falcon near a possible cliff nest site.

Sedentary

Specification

  1. Measurements
  2. spanwidth min.: 110 cm
  3. spanwidth max.: 125 cm
  4. size min.: 43 cm
  5. size max.: 49 cm
  6. Breeding
  7. incubation min.: 0 days
  8. incubation max.: 0 days
  9. fledging min.: 0 days
  10. fledging max.: 0 days
  11. broods 1
  12. eggs min.: 1
  13. eggs max.: 3
  14. Conservation Status
  15. Socotra Buzzard status Vulnerable
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