Crested Goshawk (Accipiter trivirgatus)

Crested Goshawk

Subspecies

Monotypic species

Genus

Members of the genus Accipiter are small and medium-sized hawks, often called Sparrow-hawks or Goshawks. The females are almost invariably much larger than the males – in some cases weighing twice as much – a level of size dimorphism only exceptionally reached in any other genus Falconiformes. Their wings are short and rounded; the tail usually quite long. They are well adapted for flying through dense bush. Bird-catching Sparrow-hawks generally have long and slender legs, with slender digits, the middle one being especially long. Goshawks are usually larger, with shorter, thicker tarsi and digits and a shorter middle digit. Some smaller species have goshawk-like feet and vice versa, making it difficult on a world-wide basis to subdivide the genus on this or any other broad basis. Although many accipiters feed upon birds moreso than do other hawks, some species take many mammals, especially squirrels; others take lizards, frogs, snakes, insects, even snails. In these species the legs and digits are sometimes slender, but short. Accipiters are rarely crested, but some have very attractive colour patterns. Black phases are present, especially in the tropical species. One in Australia has the only pure white phase. Accipiter is the largest genus in the family, having about fifty species. It is present worldwide, but is especially rich in Papua-New Guinea, where a small island like New Britain may have three to five endemic species or distinct sub-species.

Physical charateristics

Accipiter trivirgatus indicus of continental northern India and China has a black forehead and crown with occipital crest and grey sides to the face. The rest of the upper surfaces are dark sepia with some white marks at the base of the feathers, and a feint white bar at the base of the tail. The tail itself is light brown with four darker brown bars. The chin and throat are white with three fine black streaks. The upper breast is white streaks of brown and a red/brown patch on each side. The lower breast and stomach area are white with dark and light brown bars. The remainder of the underside is white with brown markings, except for the flight feathers which, from below, are grey-brown, with darker bars. The eyes, cere and legs are yellow. Females are larger, browner, and less clearly marked than the males. Juveniles are mostly sepia above, with some mottling. The crest is apparent. Overall they are paler than the adult and with less distinct marking.

Accipiter trivirgatus layardi of Sri Lanka is smaller and with darker markings below than the major race. Accipiter trivirgatus peninsulae of southern India has less rufous on the male. The female is lighter above and darker below. Accipiter trivirgatus trivirgatus of Sumatra is a good deal paler than A. t. indicus Accipiter trivirgatus javanicus of Java is more grey above, has a shorter crest and a more tawny breast. Accipiter trivirgatus niasensis of the Nias Islands is darker and smaller than A. t. trivirgatus Accipiter trivirgatus microstictus of Borneo is paler below than A. t. trivirgatus Accipiter trivirgatus palawanus of Palawan and surrounding islands is like A. t. microstictus but the male is more heavily barred below. Accipiter trivirgatus extimus of the Philippines, except the Polillo Islands is, in the male, like A. t. microstictus but with more rufous barring. The female has a very rufous breast. Accipiter trivirgatus castroi of the Polillo Islands of the Philippines is more blue on the back than is A. t. extimus , and more heavily marked. The tail and tarsus are also longer.

Listen to the sound of Crested Goshawk

[audio:http://www.planetofbirds.com/MASTER/ACCIPITRIFORMES/Accipitridae/sounds/Crested Goshawk.mp3]

Copyright remark: Most sounds derived from xeno-canto

wingspan min.:	65	cm	wingspan max.:	85	cm
size min.:	37	cm	size max.:	46	cm
incubation min.:	32	days	incubation max.:	32	days
fledging min.:	110	days	fledging max.:	130	days
broods:	1		eggs min.:	1
			eggs max.:	3

Range

Oriental Region : widespread

Habitat

A bird of the deep forest, the Crested Goshawk prefers areas with some clearings at altitudes from sea level to 6,000 feet or more. Old cultivation and stream banks are its favoured spots, but it can also be seen in and around areas of human habitation.

Reproduction

The Crested Goshawk nests in trees – often at a height of 100 feet or more – usually close to water. The nests are constructed by the birds themselves from sticks, and lined with green leaves. It is a sturdy construction up to twenty inches wide and twelve inches deep, and is typically used for many years. Two or three bluish white eggs are laid between December and March, depending on the area. Incubation lasts about five weeks and the young generally fledge in three to five months.

Feeding habits

The adult Crested Goshawks feed mostly on small birds, and small ground mammals and reptiles. Larger birds, up to the size of a jungle fowl, are sometimes taken.

Video Crested Goshawk

httpv://www.youtube.com/watch?v=Kb3M-MIhd_4

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). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size may be moderately small to large, 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.

Migration

Sedentary

Distribution map

Crested Goshawk distribution range map

Planet of Birds