Bucerotidae – Hornbills

Rhinoceros Hornbill Buceros rhinoceros ©Marcus Lilje Website

The Bucerotidae or Hornbills are a family of bird found in tropical and subtropical Africa, Asia and Melanesia. They are characterized by a long, down-curved bill which is frequently brightly coloured and sometimes has a casque on the upper mandible. Both the common English and the scientific name of the family refer to the shape of the bill, ‘buceros’ being ‘cow horn’ in Greek. Hornbills have a two-lobed kidney. They are the only birds in which the first and second neck vertebrae (the atlas and axis respectively) are fused together; this probably provides a more stable platform for carrying the bill. The family is omnivorous, feeding on fruit and small animals. They are monogamous breeders nesting in natural cavities in trees and sometimes cliffs. A number of species of hornbill are threatened with extinction, mostly insular species with small ranges.

Hornbills show considerable variation in size, ranging from the Black Dwarf Hornbill Tockus hartlaubi, at 102 grams and 30cm. Males are always bigger than the females, though the extent to which this is true varies according to species. The extent of sexual dimorphism also varies with body parts. For example, the difference in body mass between males and females is 1% to 17%, but the variation is 8% to 30% for bill length and 1% to 21% in wing length.

The most distinctive feature of the hornbills is the heavy bill, supported by powerful neck muscles as well as by the fused vertebrae. The large bill assists in fighting, preening, constructing the nest, and catching prey. A feature unique to the hornbills is the casque, a hollow structure that runs along the upper mandible. In some species it is barely perceptible and appears to serve no function beyond reinforcing the bill. In other species it is quite large, is reinforced with bone, and has openings between the hollow centre, allowing it to serve as a resonator for calls. In the Helmeted Hornbill the casque is not hollow but is filled with hornbill ivory and is used as a battering ram in dramatic aerial jousts. Aerial casque-butting has also been reported in the Great Hornbill.

Their plumage is typically black, grey, white, or brown, and is frequently offset by bright colours on the bill, or by patches of bare coloured skin on the face or wattles. Some species exhibit sexual dichromatism. The calls of hornbills are loud and vary distinctly between different species. They possess binocular vision, although unlike most birds with this type of vision, the bill intrudes on their visual field. This allows them to see their own bill tip and aids in precision handling of food objects with their bill. The eyes are also protected by large eyelashes which act as a sunshade. They are diurnal, generally travelling in pairs or small family groups. Larger flocks sometimes form outside the breeding season. The largest assemblies of hornbills form at some roosting sites, where as many as 2400 individual birds may be found.

According to the IOC there are 59 species of typical Hornbills in the family Bucerotidae; they are below. The HBW says 14 genera, 54 species, 78 taxa. The 59 species are:

Tanzanian Red-billed Hornbill Tockus ruahae
Western Red-billed Hornbill Tockus kempi
Damara Red-billed Hornbill Tockus damarensis
Southern Red-billed Hornbill Tockus rufirostris
Northern Red-billed Hornbill Tockus erythrorhynchus
Monteiro’s Hornbill Tockus monteiri
Von der Decken’s Hornbill Tockus deckeni
Jackson’s Hornbill Tockus jacksoni
Southern Yellow-billed Hornbill Tockus leucomelas
Eastern Yellow-billed Hornbill Tockus flavirostris

Bradfield’s Hornbill Lophoceros bradfieldi
Crowned Hornbill Lophoceros alboterminatus
African Pied Hornbill Lophoceros fasciatus
Hemprich’s Hornbill Lophoceros hemprichii
African Grey Hornbill Lophoceros nasutus
Red-billed Dwarf Hornbill Lophoceros camurus
Pale-billed Hornbill Lophoceros pallidirostris

Piping Hornbill Bycanistes fistulator
Trumpeter Hornbill Bycanistes bucinator
Brown-cheeked Hornbill Bycanistes cylindricus
White-thighed Hornbill Bycanistes albotibialis
Black-and-white-casqued Hornbill Bycanistes subcylindricus
Silvery-cheeked Hornbill Bycanistes brevis

Black-casqued Hornbill Ceratogymna atrata
Yellow-casqued Hornbill Ceratogymna elata

Black Dwarf Hornbill Horizocerus hartlaubi
White-crested Hornbill Horizocerus albocristatus

White-crowned Hornbill Berenicornis comatus

Rhinoceros Hornbill Buceros rhinoceros
Great Hornbill Buceros bicornis
Rufous Hornbill Buceros hydrocorax

Helmeted Hornbill Rhinoplax vigil

Palawan Hornbill Anthracoceros marchei
Oriental Pied Hornbill Anthracoceros albirostris
Malabar Pied Hornbill Anthracoceros coronatus
Sulu Hornbill Anthracoceros montani
Black Hornbill Anthracoceros malayanus

Malabar Grey Hornbill Ocyceros griseus
Sri Lanka Grey Hornbill Ocyceros gingalensis
Indian Grey Hornbill Ocyceros birostris

Tickell’s Brown Hornbill Anorrhinus tickelli
Austen’s Brown Hornbill Anorrhinus austeni
Bushy-crested Hornbill Anorrhinus galeritus

Rufous-necked Hornbill Aceros nipalensis

Blyth’s Hornbill Rhyticeros plicatus
Narcondam Hornbill Rhyticeros narcondami
Wreathed Hornbill Rhyticeros undulatus
Sumba Hornbill Rhyticeros everetti
Plain-pouched Hornbill Rhyticeros subruficollis
Knobbed Hornbill Rhyticeros cassidix

Walden’s Hornbill Rhabdotorrhinus waldeni
Writhed Hornbill Rhabdotorrhinus leucocephalus
Sulawesi Hornbill Rhabdotorrhinus exarhatus
Wrinkled Hornbill Rhabdotorrhinus corrugatus

Luzon Hornbill Penelopides manillae
Mindoro Hornbill Penelopides mindorensis
Mindanao Hornbill Penelopides affinis
Samar Hornbill Penelopides samarensis
Visayan Hornbill Penelopides panini

Number of Species
  • Number of bird species: 59

Useful Reading
  • Hornbills of the World: A Photographic Guide

    by Pilai Poonswad (Author), Alan Kemp (Author), Morten Strange (Author) | Paperback | May 2013 | Draco Publishing | 212 pages, 400+ colour photos, colour distribution maps ISBN: 9789810735289 Buy this book from NHBS.com
  • The Ecology and Conservation of Asian Hornbills

    - Farmers of the Forest by Margaret F Kinnaird and Timothy G O'Brien352 pages, 15 col plates, 91 halftones, 27 line drawings, 32 tabs. University of Chicago Press - Hardcover due February 2008 ISBN: 9780226437125 Buy this book from NHBS.com
  • The Hornbills: Bucerotiformes

    (Bird Families of the World series)by Martin Woodcock (Illustrator); A. C. Kemp Oxford University Press; (October 1996) ISBN: 019857729X Buy this book from NHBS.com
Organisations
  • Hornbill Research Foundation

    Webpage
    The Hornbill Research Foundation was set up following a project initiating research into the ecology of hornbills by the faculty of science, Mahidol University in 1980. The study was begun in Khao Yai National Park, Thailand and later expanded to include forests in western and southern regions. Apart from the biology and ecology of hornbills, research was also made into their range and status throughout the country. As a result, an increasing number of research workers were needed to cope with the expansion of project and the maintenance of uninterrupted record-keeping. This led to the creation of a foundation which H.R.H. Princess Mahachakri Sirinthorn was graciously pleased to name and The Hornbill Research Foundation was set up in July 1993…
Other Links
  • Checklist of Hornbills of the World

    Website
    Checklist & distribution.
Photographers & Artists
  • Bushy-crested Hornbill Anorrhinus galeritus

    Gallery
    Excellent image…
  • Southern Yellow-billed Hornbill Tockus leucomelas

    Gallery
    Excellent images…
  • White Crowned Hornbill Aceros comatus

    Gallery
    Stunning images

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