Rhabdotorrhinus exarhatus
Red List Status: VU – Vulnerable, criteria A4cd (IUCN 2018)
Distribution: Endemic to Indonesia; occurs on Sulawesi and some adjacent islands. Two subspecies recognised: P. e. exarhatus occurs on north Sulawesi and Lembeh Island; P. e. sanfordi has ridges on the lower mandible of its bill and occurs on south Sulawesi and the islands of Muna and Butung.
Description: 45 cm. Female 370 g. Small-sized and entirely black hornbill, except for male’s white face stained with yellow, possibly from preen oil. Female is smaller with all-black plumage and base of bill. Juveniles of both sexes like adult male, but almost casqueless bill smaller and dark yellow. Adult facial colours develop when juvenile 80-105 days old.
Voice: The frequent call of this species is a piercing four-syllable kerrekerre …. kerrekerre.
Habits: Occurs in primary rainforest, mainly in the lowlands to 650 m elevation, but has been recorded to 1,100 m. Extends from mature forest into secondary forest and more open areas nearby. Fruit is the main food (85%) and some animal prey, mainly invertebrates. 34 different species of fruiting trees and shrubs have been identified as food sources. This small hornbill moves inside or just below the canopy of the forest in small family groups. It is apparently sedentary and territorial; has been reported to chase the sympatric but much larger Knobbed Hornbill. The home range when breeding has been measured as 0.7-1.4 km²; another survey found an all-year home range for a group at 1.5-2.0 km². It lives in groups of up to 20 individuals; it is believed that only the dominant pair will breed, with the rest of the group acting as helpers.
