Ubara asiatica

Identificazione

This medium-sized bustard is about 65 cm (26 in) long with a 140 cm (55 in) wingspan. It is brown above and white below, with black stripes down the sides of the neck. In flight, the long wings show large areas of black and brown on the flight feathers and a white patch at the base of the primaries. From below the wing is mostly white with a black trailing edge. Sexes are similar, but the female is smaller and paler above.<p>Males and females are nearly identical in plumage but males are slightly larger than females. A study of the morphometrics of MacQueen's bustards from Pakistan based on about 79 individuals of known sex showed that the males were 9 to 15% larger than females on most measurements. The use of discriminant analysis allowed correct identification of the sexes based on morphometrics in about 99% of the cases.<p>MacQueen's bustard is very silent except for the sounds that males make in their display. Like other bustards, they have a flamboyant display, raising the white feathers of the head and throat and withdrawing the head while walking around a chosen lek site.

Tassonomia

Otis macqueenii was proposed by John Edward Gray in 1834 for a bustard from India drawn by Thomas Hardwicke.It was long regarded a subspecies of the African houbara bustard Chlamydotis undulata. It was classified as a distinct species in 2003.<p>The genus name Chlamydotis is from Ancient Greek khlamus, a horseman's cloak with weights sewn into the corners, and otis, bustard.<p>MacQueen's bustard is larger than the houbara and much paler. The feathers on the top of the head include some long and curved feathers which are white or black with white bases. In the houbara, these crest feathers are all white and the difference is evident during the display of the male. The lack of intermediate forms in the region where the ranges of MacQueen's bustard and houbara bustard meet, presumed to be in the Nile valley, differences in morphology and display behaviour led to their being elevated to full species. The houbara bustard now refers only to the North African population, included as the nominate subspecies C. undulata undulata and a small population on the Canary Islands (C. u. fuertaventurae).<p>Estimates based on the divergence of mitochondrial DNA sequence suggest that the species separated from the common ancestors of C. u. undulata and C. u. fuertaventurae nearly 430,000 years ago. This divergence may have begun 900,000 years ago, at a time of extreme aridity. The wide dispersal abilities of MacQueen's bustard ensure that their genes are more well mixed unlike the geographically structured genetic patterns shown by the African houbara.

Nome scientifico

Chlamydotis macqueenii

Autorità

(Gray, JE, 1832)

Ordine

Otidiiformes

Famiglia

Otididae

Genere

Chlamydotis

Areale e habitat

MacQueen's bustard occurs from the east of the Sinai Peninsula to the Caspian Sea and extending east to the Gobi Desert in Mongolia. Birds from the northern populations winter further south in Pakistan (mainly in western Balochistan) and in the dry arid zone of western India. Vagrants have historically been found as far west and north as Britain and as far south as northern Kerala (Kanhangad). A bird was shot in 1847 at Lincolnshire, Yorkshire in 1898, and another in Aberdeenshire in 1898 all in the month of October. Possibly the last of these vagrants visited Suffolk in November–December 1962. This species breeds in deserts and other very arid sandy areas. A study of their habitat in Saudi Arabia found the species to be very dependent on good vegetation cover and tended to be found in areas with dense growth of scrub vegetation, particularly Capparis spinosa. A study in the steppes of Iran found that nest sites were chosen mainly in locations with high densities of insect prey which in turn were related to vegetation characteristics.<p>Their migrations have been tracked using satellite transmitters. Mongolian birds leave the wintering areas in Afghanistan and Pakistan from mid to late March and arrive in their breeding grounds after about two months of flying, taking a path that avoids the high mountains of the Himalayas. They fly about 220 km (140 mi) a day and cover a total of 4,400 km (2,700 mi) with stopovers along the path. They spend about four months in their breeding territories before setting off again and reach their winter grounds from October to December.<p>Satellite tracking of 48 individual houbaras across multiple migrations showed that this species uses the local temperature to time their spring migration departure.

Migrazione

Migratori completi

Comportamento

Comportamento migratorio: Migratori completi.

Conservazione

Tendenza della popolazione: in diminuzione.

Tendenza della popolazione

in diminuzione