Indien-Grautoko

Bestimmung

The Indian grey hornbill is a medium-sized hornbill, measuring around 61 cm (24 in) in length. The upper parts are greyish brown and there is a slight trace of a pale supercilium. The ear coverts are darker. The flight feathers of the wing are dark brown with a whitish tip. The tail has a white tip and a dark subterminal band. They have a red iris and the eyelids have eyelashes. The casque is short and pointed.<p>The male has a larger casque on a dark bill, and the culmen and lower mandible are yellowish. The bare skin around the eye is dark in the male, but sometimes pale reddish in females. The female has a more yellowish bill with black on the basal half and on the casque.The juveniles lack the casque, and the bare skin around the eye is dull orange.

Taxonomie

Wissenschaftlicher Name

Ocyceros birostris

Autorität

(Scopoli, 1786)

Ordnung

Bucerotiformes

Familie

Bucerotidae

Gattung

Ocyceros

Verbreitung und Lebensraum

The species is found mainly on the plains up to about 2,000 ft (610 m). It is found from the foothills of the Himalayas southwards, bounded to the west by the Indus system and to the east by the Ganges Delta. It may make local movements in the drier western region. It is found even in cities that have old avenue trees. The species has been observed, usually in pairs, in Dharamsala town (Himachal Pradesh) at about 1500 to 1600 masl during summer and in the rainy season (May to September, 2017). and does not overlap much with the Malabar grey hornbill of the Western Ghats.

Zugverhalten

Resident species

Verhalten

The call is a squealing call somewhat like that of a black kite. The flight is heavy and involves flapping interspersed with glides. They are found in pairs or small groups.<p>The nesting season is April to June and the clutch varies from one to five very symmetrical white eggs. Indian grey hornbills usually nest in tree hollows on tall trees. An existing hollow may be excavated further to suit. The female enters the nest hollow and seals the nest hole, leaving only a small vertical slit through which the male feeds her. The nest entrance is sealed by the female using its excreta and mud-pellets supplied by the male. While inside the nest, the female moults her flight feathers and incubates the eggs. The male provides the nest inmates with a steady supply of bark pieces to ensure that the excreta is removed from the nest by absorption and adsorption and to help maintain the micro-climate within the next cavity. The regrowth of the female's feathers coincides with the maturity of the chicks, at which point the nest is broken open.<p>A study at a nest near Mumbai noted that the key fruiting trees on which the hornbills fed were Streblus asper, Cansjera rheedii, Carissa carandas, Grewia tiliaefolia, Lannea coromandelica, Ficus spp., Sterculia urens and Securinega leucopyrus. They are also known to take molluscs, scorpions, insects, small birds (they have been recorded removing and possibly preying on rose-ringed parakeet chicks) and reptiles in their diet They are known to feed on the fruits of Thevetia peruviana, which are known to be toxic to many vertebrates.<p>They are almost completely arboreal, but very rarely descend to the ground to pick up fallen fruits, to dust bathe, or to pick up mud pellets to seal the nest cavity during the nesting period. They indulge in various social activities, including bill-grappling and aerial jousting.

Schutzstatus

Bestandstrend

stable