Sulawesi redknobbed hornbill

Aceros cassidix

SUBFAMILY

Bucerotinae

TAXONOMY

Buceros cassidix Temminck, 1823, Sulawesi. Sometimes classified as Rhyticeros cassidix. Monotypic.

OTHER COMMON NAMES

English: Red-knobbed hornbill, knobbed hornbill, island hornbill, Celebes hornbill, Sulawesi wrinkled hornbill; French: Calao a cimier; German: Helmhornvogel; Spanish: Cálao grande de Célebes.

PHYSICAL CHARACTERISTICS

27.6-31.5 in (70-80 cm); female weight unknown, male 5.2-5.5 lb (2.36-2.5 kg). Black with white tail; high wrinkled casque is red; neck is rufous (male) or black (female); ridged yellow beak with blue throat skin.

DISTRIBUTION

Indonesian island of Sulawesi and neighboring islands of Lem-beh, Togian, Muna, and Buton.

HABITAT

Prefers primary lowland rainforest below 3,600 ft (1,100 m) altitude.

BEHAVIOR

Wide-ranging, non-territorial bird. Usually seen in pairs and observed in large numbers at fruiting figs, rarely up to 120 individuals. Emits loud barking calls that can be heard more than 1.2 mi (2 km) away. High mobility and reliance on fruit makes these hornbills critical agents of seed dispersal and forest regeneration.

FEEDING ECOLOGY AND DIET

One of the most frugivorous hornbills with a diet of up to 90% fruit comprised of more than 60 species during a year. Forage primarily in the top of the canopy.

REPRODUCTIVE BIOLOGY

Nests in high densities of up to 10 pairs/km2 beginning June/July at end of rainy season, so fledging is timed with fruiting peak. Lays two to three eggs; incubation 32-35 days and nestling period c. 100 days resulting in nesting cycle of c. 139 days. Female emergence highly variable, ranging from 58 to 140 days but generally before chick. Only one chick fledges but nesting success high at an average of 80%.

CONSERVATION STATUS

Not threatened. Locally common attaining densities of 130 birds/mi2 (51 birds/km2) in Tangkoko Nature Reserve, North Sulawesi—the highest density ever recorded for a forest hornbill. Distribution, however, becoming restricted and patchy due to massive deforestation.

SIGNIFICANCE TO HUMANS

Feathers and casques, believed to impart power and insure invincibility, are used to decorate headdresses and drums for the Cakalele, a traditional warrior's dance. Less frequently, heads are hung in rafters to bring power to the homes and protect against evil spirits. Meat also eaten. ♦

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