Anorrhinus austeni Jerdon, 1872

Plumage and Bare Skin Features

Austen's brown hornbill (Anorrhinus austeni Jerdon, 1872) has dark brown upperparts, including the back, wings, and tail, with lighter-colored belly, cheeks, and throat. Its tail and wings have white tips, and it has blue bare skin surrounding the eyes.

Sexual Dimorphism Overview

This species is sexually dimorphic.

Bill and Casque Differences

Females have ivory white bills and casques, while males have cream-colored bills and casques.

Plumage Differences Between Sexes

Females have grey-brown throats, bellies, and cheeks; males have whitish throats and cheeks paired with a reddish belly. Females also have a yellow wash of color below the eye.

Juvenile Characteristics

Juveniles resemble adult males, but have short yellow bills, orange skin around the eyes, and pale-brown feather tips.

Adult Size and Weight

Adult males weigh 710–900 g (25–32 oz) and measure 73–80 cm (29–31 in) in length; females are smaller in size.

Geographic Range

Austen's brown hornbill is distributed across northeastern India, central and northern Thailand, Myanmar, Laos, Vietnam, and Cambodia. It was historically found in China, but no recent reports of the species there exist.

Population Status Across Range

It is rare across most of its range, and occurs mainly in protected forests within national parks and sanctuaries, such as Patkai Wildlife Sanctuary and Namdapha Tiger Reserve. It is common in Laos, though its population in the country is declining.

Preferred Habitat Types

The species lives primarily in dense lowland and foothill evergreen forests, and occurs less commonly in deciduous forests.

Elevational Range

It has been recorded up to 1,000 m (3,300 ft) in India, 1,500 m (4,900 ft) in Southeast Asia, and 1,800 m (5,900 ft) in Tibet.

Movement Within Forest

It moves through forest at or below the canopy level, but uses all canopy layers equally.

Breeding System

Austen's brown hornbill is a monogamous cooperative breeder. A dominant breeding pair has an average of two non-breeding helpers, though the number of helpers can range from zero to five.

Helper Characteristics

Helpers are the pair's own non-breeding offspring, and are mostly adult males, but sometimes juveniles.

Helper Nest Duties

Helpers bring food to the nesting female and chicks, and defend the nest from predators, conspecifics, and other closely related hornbill species. Food is delivered to the nest via regurgitation.

Nest Site Characteristics

This hornbill nests in natural tree cavities or abandoned woodpecker holes, located around 5–7 m (16–23 ft) above the ground, and sometimes as high as 27 m (89 ft). Tree species used for nesting include magnolia, hollong, Anthoshorea assamica, and Artocarpus chama.

Breeding Timing

Breeding activity begins between February and March depending on location, usually before the monsoon season. The main breeding season lines up with the peak availability of non-fig fruits.

Female Nesting Behavior

Like other hornbills, the female seals herself inside the nesting cavity and moults her flight feathers during nesting.

Clutch Size and Incubation

The average clutch size is two eggs, and rarely reaches up to five. The incubation period lasts 24–30 days, and the nesting period lasts 57–62 days.

Fledging and Nest Cycle Duration

The female and chicks all fledge at the same time, between May and July depending on location. The full nesting cycle lasts 73–112 days.