Aceros nipalensis (Hodgson, 1829)

Nomenclature

This species is scientifically named Aceros nipalensis (Hodgson, 1829), commonly called the rufous-necked hornbill.

Adult Male Plumage

For adult males, the head, neck, and lower body are rufous, with deeper color on the flanks and abdomen. The middle primaries and the lower half of the tail are tipped white. The rest of the hornbill's plumage is glossy dark-green and black, and the lower tail-covert feathers are chestnut mixed with black.

Adult Female Plumage

Adult females are entirely black except for the end of their tail and the tips of the middle primaries, which are white.

Juvenile Plumage & Beak Features

Juvenile hornbills look similar to adult individuals of the same sex, but they do not have ridges at the base of the upper beak. The beak does not have a true casque, but is thickened at the base.

Beak Ridge Characteristics

The upper beak has several dark ridges; these ridges are absent in young birds, and their number increases with age up to around seven. The beak commissure is broken in both sexes.

Overall Distribution Range

The rufous-necked hornbill has the northernmost distribution among its group, ranging from Northeast India, central Bhutan to western Thailand and northwestern Vietnam. Its total range covers 1,163,811 km² (449,350 sq mi), of which 825,837 km² (318,857 sq mi) is forested.

Protected Area Coverage

Within this range, the species occurs in 90 protected areas that cover 54,955 km² (21,218 sq mi) of protected forest, but these protected areas only include 7% of the species' optimal habitat.

Indian Distribution Records

Mahananda Wildlife Sanctuary in West Bengal marks the westernmost limit of its distribution; the species has also been recorded in Buxa Tiger Reserve, Manas National Park, Eaglenest Wildlife Sanctuary, Sessa Orchid Sanctuary, Kamlang Wildlife Sanctuary, Namdapha National Park and Pakke Tiger Reserve.

Habitat & Elevation Range

It predominantly lives in ridged and hilly forests, mainly temperate broadleaf and mixed forests at elevations between 150 m (490 ft) and 2,200 m (7,220 ft). It has also been recorded in dry woodland.

Nesting Behavior

The nesting period of this species runs from March to June, and it prefers to nest in tall trees with broad girths.

Seasonal Movement

Communities of these hornbills move seasonally between different forests to forage on fruiting trees whose availability changes with local conditions.

Egg Shape

In 1889, Hume described the egg of this species as follows: the egg is a broad oval, slightly compressed towards one end, making it slightly pyriform.

Egg Shell Texture

The shell is strong and thick, but coarse and completely without gloss, and is pitted all over with minute pores.

Egg Coloration

The egg is a very dirty white with a pale dirty yellowish tinge; when examined closely, it is faintly stippled all over with minute purer white specks, which form because dirt does not reach the bottom of the pores.

Egg Dimensions

The egg measures 2.25 by 1.75 inches.