Knobbed Hornbill

Rhyticeros cassidix

A huge black hornbill with a prominent knob on the bill, conspicuous red “gills” on the sides of the beak, a turquoise-blue throat pouch, and a white tail. Males have a red casque and rufous neck, females a yellow knob and black neck. Juveniles resemble male, but with an entirely yellow casqueless bill. Found in pairs or groups in canopy of forested and wooded areas of lowlands and hills. Larger and more colorful than Sulawesi Hornbill. Gives powerful, short “krok” notes and a more drawn-out “oooo-aa-ooo-aaa.”

Identification

This is a large black hornbill with a yellow bill, white tail feathers, pale blue skin around eye, blackish feet and bare dark blue throat. The male has rufous/buff face and neck, orange-red eyes, and a high red casque on the top of his bill. The female has a black face and neck, a yellow casque, and brownish eyes.

Taxonomy

Scientific name
Rhyticeros cassidix
Authority
(Temminck, 1823)
Order
Bucerotiformes
Family
Bucerotidae
Genus
Rhyticeros

Range and habitat

An Indonesian endemic, the knobbed hornbill is found in Sulawesi, Buton, Lembeh, Togian and Muna Island. It inhabits evergreen forest at an elevation of up to 1,800 m and also makes use of secondary forest, woodland and plantations for foraging.

Migration
Resident species

Behavior

As with other hornbills, the knobbed hornbill is believed to be monogamous. Its diet consists mainly of fruits, but it will also take insects and small vertebrates. Breeding season spans 27–30 weeks and appears to be triggered by a dramatic reduction in rainfall. The female seals itself inside a tree hole for egg-laying using its own feces. During this time, the male will provide foods for the female and the young through a slit in the seal.<p>Knobbed hornbills are important seed dispersers in their habitat and influence the initial fate of seeds of several tropical forest tree species.

Conservation

The species is currently classified as vulnerable by the IUCN. Despite being locally very common, they are threatened by habitat destruction from logging (since they depend on large and mature trees for breeding) and to some extent by hunting.

Population trend
declining

Photos

Distribution

Other Birds

Sabine's Puffback

Sabine's Puffback

Dryoscopus sabini

A relatively large-billed shrike-like bird primarily found in lowland forest canopy. Male is white below and iridescent black above except for a white rump. The female is overall reddish brown, with more reddish wings and a grayish hood. Similar to several bicolored shrikelike birds in the region, but note Sabine’s Puffback’s large bill, striking sexual dimorphism, and unique song, which consists of a distinctive series of long whistles descending in pitch before arriving at a single repeated pitch, growing louder, and then ending suddenly. Songs can sometimes last several minutes, and are more reminiscent of some Yellow Longbill songs than of the songs of other puffbacks. Calls include typical puffback-like rattles and harsh calls. 

Garnet Robin

Garnet Robin

Eugerygone rubra

A small bird of montane forest. Gray underparts and face, paler to whitish on the throat and belly, black wing with white flash and black tail with white outer tail feathers and tips to the undertail. Note the white eye-ring which is broader at the back. Male has a dark, reddish back and the female olive green. Distinctive horizontal posture and twitching wings and tail. No other similar-sized bird in this habitat have a white patch in the wing. Song, a repeated, high-pitch, tinkling “twiddle-dee”.

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