Family Hornbills (Bucerotidae)

Least Concern

Red-billed Hornbill (Tockus erythrorhynchus)

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Taxonomy

French: Calao à bec rouge German: Nördlicher Rotschnabeltoko Spanish: Toco piquirrojo
Other common names: African Red-billed Hornbill, Ruaha Hornbill (ruahae), South African Red-billed Hornbill (rufirostris)
Taxonomy:

Buceros erythrorhynchus

Temminck

, 1823,

Mora, Cameroon

.

Closest to T. monteiri, but close also to T. flavirostris, T. leucomelas and T. deckeni (and presumably jacksoni), on basis of similar calls and behaviour, and DNA studies#R. Recent trend towards splitting all subspecies as separate species resisted here pending further, stronger evidence, but some are clearly distinctive and one, T. damarensis, achieves species status (see above), while another form, ruahae, treated since description as full species (see HBW SV), although notably distinct from nominate erythrorhynchus, differs from subspecies rufirostris only in its black vs pale pink periorbital skin (score 3) and grey streaks on face, ear-coverts, neck and upper breast (1). Population from S Mozambique to KwaZulu-Natal described as race degens on basis of smaller size, but differences slight; birds of N Botswana (Ngamiland) formerly separated as race ngamiensis, which sometimes still accepted#R. Type specimen lost and original description gave only a generalized range, so a type locality (Podor, Senegal) was proposed, in 1960; however, birds of that region have since been discovered to have have black facial skin, whereas illustrations associated with original description show birds with pale facial skin, so a new type locality and a neotype were recently established to accord with these#R. Four subspecies currently recognized.

What do the figures in brackets mean? Learn more about the scoring system.
Subspecies and Distribution
  • T. e. kempi Tréca & Érard, 2000 – Western Red-billed Hornbill – S Mauritania and Senegambia E to Inner Niger Delta.
  • T. e. erythrorhynchus (Temminck, 1823) – Northern Red-billed Hornbill – Inner Niger Delta E to Eritrea, and Somalia, S to Kenya and N Tanzania.
  • T. e. ruahae Kemp & Delport, 2002 – Tanzanian Red-billed Hornbill – C & W Tanzania.
  • T. e. rufirostris (Sundevall, 1850) – Southern Red-billed Hornbill – S Angola and NE Namibia E to Zambia and S Malawi and S to NE South Africa.
  • Descriptive notes

    35 cm; male 124–185 g, female 90–151 g (nominate), male 182 g, female 148 g (race kempi), male 128 g, female 125 g (race ruahae). Small, black-and-white hornbill with spotted wing-coverts, white in outer tail, and long, slender, red bill. Male nominate race has thin yellow basal line of bill, black inner half of lower mandible; bare skin around eye and on throat yellow to pinkish; eyes brown. Female smaller, lower mandible with only small black patch. Juvenile resembles adult male, but bill shorter and pale ­orange. Races differ mainly in size, eye colour, and colour of facial skin and feathering: kempi smaller, with black facial skin; ruahae is comparatively small, with white facial feathering, yellow eyes and black facial skin; rufirostris slightly larger than nominate, darker grey on face to upper breast, less black on bill, facial skin flesh-coloured, eyes yellow.

    ssp kempi   Western Red-billed Hornbill

    Drawing by Tim Worfolk
    ssp kempi   Western Red-billed Hornbill
    Descriptive notes:

    35 cm; male 124–185 g, female 90–151 g (nominate), male 182 g, female 148 g (race kempi), male 128 g, female 125 g (race ruahae). Small, black-and-white hornbill with spotted wing-coverts, white in outer tail, and long, slender, red bill. Male nominate race has thin yellow basal line of bill, black inner half of lower mandible; bare skin around eye and on throat yellow to pinkish; eyes brown. Female smaller, lower mandible with only small black patch. Juvenile resembles adult male, but bill shorter and pale ­orange. Races differ mainly in size, eye colour, and colour of facial skin and feathering: kempi smaller, with black facial skin; ruahae is comparatively small, with white facial feathering, yellow eyes and black facial skin; rufirostris slightly larger than nominate, darker grey on face to upper breast, less black on bill, facial skin flesh-coloured, eyes yellow.

    ssp erythrorhynchus   Northern Red-billed Hornbill

    Drawing by Tim Worfolk
    ssp erythrorhynchus   Northern Red-billed Hornbill
    Descriptive notes:

    35 cm; male 124–185 g, female 90–151 g (nominate), male 182 g, female 148 g (race kempi), male 128 g, female 125 g (race ruahae). Small, black-and-white hornbill with spotted wing-coverts, white in outer tail, and long, slender, red bill. Male nominate race has thin yellow basal line of bill, black inner half of lower mandible; bare skin around eye and on throat yellow to pinkish; eyes brown. Female smaller, lower mandible with only small black patch. Juvenile resembles adult male, but bill shorter and pale ­orange. Races differ mainly in size, eye colour, and colour of facial skin and feathering: kempi smaller, with black facial skin; ruahae is comparatively small, with white facial feathering, yellow eyes and black facial skin; rufirostris slightly larger than nominate, darker grey on face to upper breast, less black on bill, facial skin flesh-coloured, eyes yellow.

    Drawing by Tim Worfolk
    ssp erythrorhynchus   Northern Red-billed Hornbill
    Descriptive notes:

    35 cm; male 124–185 g, female 90–151 g (nominate), male 182 g, female 148 g (race kempi), male 128 g, female 125 g (race ruahae). Small, black-and-white hornbill with spotted wing-coverts, white in outer tail, and long, slender, red bill. Male nominate race has thin yellow basal line of bill, black inner half of lower mandible; bare skin around eye and on throat yellow to pinkish; eyes brown. Female smaller, lower mandible with only small black patch. Juvenile resembles adult male, but bill shorter and pale ­orange. Races differ mainly in size, eye colour, and colour of facial skin and feathering: kempi smaller, with black facial skin; ruahae is comparatively small, with white facial feathering, yellow eyes and black facial skin; rufirostris slightly larger than nominate, darker grey on face to upper breast, less black on bill, facial skin flesh-coloured, eyes yellow.

    ssp ruahae   Tanzanian Red-billed Hornbill

    Drawing by Tim Worfolk
    ssp ruahae   Tanzanian Red-billed Hornbill
    Descriptive notes:

    35 cm; male 124–185 g, female 90–151 g (nominate), male 182 g, female 148 g (race kempi), male 128 g, female 125 g (race ruahae). Small, black-and-white hornbill with spotted wing-coverts, white in outer tail, and long, slender, red bill. Male nominate race has thin yellow basal line of bill, black inner half of lower mandible; bare skin around eye and on throat yellow to pinkish; eyes brown. Female smaller, lower mandible with only small black patch. Juvenile resembles adult male, but bill shorter and pale ­orange. Races differ mainly in size, eye colour, and colour of facial skin and feathering: kempi smaller, with black facial skin; ruahae is comparatively small, with white facial feathering, yellow eyes and black facial skin; rufirostris slightly larger than nominate, darker grey on face to upper breast, less black on bill, facial skin flesh-coloured, eyes yellow.

    Drawing by Tim Worfolk
    ssp ruahae   Tanzanian Red-billed Hornbill
    Descriptive notes:

    35 cm; male 124–185 g, female 90–151 g (nominate), male 182 g, female 148 g (race kempi), male 128 g, female 125 g (race ruahae). Small, black-and-white hornbill with spotted wing-coverts, white in outer tail, and long, slender, red bill. Male nominate race has thin yellow basal line of bill, black inner half of lower mandible; bare skin around eye and on throat yellow to pinkish; eyes brown. Female smaller, lower mandible with only small black patch. Juvenile resembles adult male, but bill shorter and pale ­orange. Races differ mainly in size, eye colour, and colour of facial skin and feathering: kempi smaller, with black facial skin; ruahae is comparatively small, with white facial feathering, yellow eyes and black facial skin; rufirostris slightly larger than nominate, darker grey on face to upper breast, less black on bill, facial skin flesh-coloured, eyes yellow.

    ssp rufirostris   Southern Red-billed Hornbill

    Drawing by Tim Worfolk
    ssp rufirostris   Southern Red-billed Hornbill
    Descriptive notes:

    35 cm; male 124–185 g, female 90–151 g (nominate), male 182 g, female 148 g (race kempi), male 128 g, female 125 g (race ruahae). Small, black-and-white hornbill with spotted wing-coverts, white in outer tail, and long, slender, red bill. Male nominate race has thin yellow basal line of bill, black inner half of lower mandible; bare skin around eye and on throat yellow to pinkish; eyes brown. Female smaller, lower mandible with only small black patch. Juvenile resembles adult male, but bill shorter and pale ­orange. Races differ mainly in size, eye colour, and colour of facial skin and feathering: kempi smaller, with black facial skin; ruahae is comparatively small, with white facial feathering, yellow eyes and black facial skin; rufirostris slightly larger than nominate, darker grey on face to upper breast, less black on bill, facial skin flesh-coloured, eyes yellow.

    Drawing by Tim Worfolk
    ssp rufirostris   Southern Red-billed Hornbill
    Descriptive notes:

    35 cm; male 124–185 g, female 90–151 g (nominate), male 182 g, female 148 g (race kempi), male 128 g, female 125 g (race ruahae). Small, black-and-white hornbill with spotted wing-coverts, white in outer tail, and long, slender, red bill. Male nominate race has thin yellow basal line of bill, black inner half of lower mandible; bare skin around eye and on throat yellow to pinkish; eyes brown. Female smaller, lower mandible with only small black patch. Juvenile resembles adult male, but bill shorter and pale ­orange. Races differ mainly in size, eye colour, and colour of facial skin and feathering: kempi smaller, with black facial skin; ruahae is comparatively small, with white facial feathering, yellow eyes and black facial skin; rufirostris slightly larger than nominate, darker grey on face to upper breast, less black on bill, facial skin flesh-coloured, eyes yellow.

    Voice

    Gives high-pitched, single, clucking notes in contact or low-intensity alarm, becoming an irregular series when alarm more intense; notes become double-noted in display, “kok-kok-kok-kokok-kokok-kokok” (typically given from prominent perch in early morning); utters screeching notes in fright, while young beg with high-pitching piping notes and both they and female utter squawks when accepting food.

    Habitat

    Open savanna and woodland, especially with sparse ground cover, extending into drier thorn-scrub and more hilly areas in sub-Saharan areas, but also denser forest formations in N Ghana, as well as dry Anogeissus forest and partially cultivated Vitellaria orchards; in Malawi and Zambia, commonest in tall mopane woodland; occurs at up to 2120 m in Ethiopia. Race ruahae inhabits Brachystegia woodland, Acacia and Combretum woodland, and riverine forest, perhaps mainly in areas with baobab trees (Adansonia).

    Food and feeding

    Beetles, termites, fly larvae and grasshoppers important in diet, but takes small vertebrates such as geckos, nestlings (e.g. of Red-billed Quelea Quelea quelea and Crimson-breasted Shrike Laniarius atrococcineus) and (usually dead) rodents when these available; some fruit eaten (e.g. Ficus thonningii, Boscia senegalensis, B. coriaceae, Premna resinosa, Dictyoptera, Commiphora holtziana and C. riparia), and in dry season even grain, especially by nominate race. Study in Transvaal found that insects were most important constituent of diet, with beetles (especially dung beetles) and their larvae, grasshoppers, termites, ants and fly larvae the most important of these, but a wide range of (generally small) arthropod prey is accepted including antlions, butterflies, crickets, solifugids, scorpions and centipedes. In Senegal, seasonally favoured invertebrates and fruit in summer, and grain in winter. For race ruahae stomach contents of one specimen consisted of insect remains, including ants (Formicidae), and seeds; another stomach held insect remains, including a beetle larva (Coleoptera), and seeds. Most (94% in one study) food obtained on ground, particularly by digging in dung and debris for small insects (35% in wet season, 65% in dry season). Rarely takes food in flight. Often joins bird parties (in Ethiopia, including with Stresemann’s Bushcrow Zavattariornis stresemanni), and sometimes forms single-species flocks of up to 50 individuals. Nominate race forages more often in trees, especially when competitive congeners are absent.

    Breeding

    Lays usually 4–7 weeks after start of rains, but has been suggested that breeding starts before the rains in Ghana: Mar–Nov in W Africa, various months in NE & E Africa, e.g. Apr–May in Somalia and Feb–Aug in Ethiopia, and Feb–Mar in Namibia, and Sept–Mar in C & S Africa; at least Jan–Mar in SW Tanzania (race ruahae). Territorial in pairs; mean territory size c. 10 ha in Transvaal. Nest in natural cavity 0·3–9·1 m (mean 3·2 m in S Africa, 1·9 m in Kenya) up in tree (e.g. Adansonia, Sclerocarya, Acacia, Combretum, Lonchocarpus, Diospyros, Albizia, Colophospermum, Lannea, Schotia, Delonix, Commiphora, Ehretia), in old hole of barbet or woodpecker, or in bee-hive log, lined with green leaves and some bark and dry grass; recorded also breeding in a hollow brickstone wall#R; male selects site, and sometimes brings lining and sealing materials to assist, female seals entrance with own droppings and food remains; often takes over nest of other hornbill species, once when still containing chicks, whereafter both adults (the other Lophoceros nasutus) indiscriminately fed all of the young. Will use same nest-hole in subsequent seasons. Clutch 2–7 white eggs, size 31·5–37 mm × 22–25·5 mm (number of eggs varies in response to rainfall and egg size within a clutch appears to decline as laying proceeds), laid 1–7 days apart following pre-laying period 3–24 days; incubation 23–25 days, starting from first egg; female and chicks fed by male, with latter being generally fed 1–17 times/hour, but up to 50 times/hour (peaking when chicks half-grown); female moults remiges and rectrices simultaneously during laying, but emerges when oldest chick 16–24 days old; fledging 39–50 days, although achieves peak mass at 28–38 days. Young capable of breeding in first season following fledging. Breeding success: in Transvaal, 45% of eggs produced fledged young (from 26 nests), with 90% of attempts resulting in at least one fledgling (mean 1·5 young per effort), while in Kenya 59% of eggs hatched and 94% of eggs that hatched resulting in fledged young, with overall productivity at 11 nests being 1·4 young per attempt; main causes of failure are death of male (raptors such as Bateleur Terathopius ecaudatus, Wahlberg’s Eagle Hieraaetus wahlbergi, Tawny Eagle Aquila rapax and Gabar Goshawk Micronisus gabar, among others are known to kill adults), infertile or cracked eggs, starvation of some chicks in large broods, nest flooding and damage to nest-tree. In captivity, capable of laying again within six weeks of chicks fledging. One adult male survived more than 18 years in captivity.

    Movements

    In some areas, congregates during dry season in flocks of several hundred birds, which make local movements in search of food; this is evident in Zambezi Valley of Zimbabwe and, especially, arid sub-Saharan zones, where it may amount to regular migration. Unusual drowning of c. 1000 birds in L Kariba, in Zimbabwe, apparently on migration. Wandering birds occasionally recorded in SE Ghana and Lower Shire Valley of Malawi.

    Status and conservation

    Not globally threatened (Least Concern). A widespread and locally common (even abundant) species (e.g. in Ethiopia and across N Ghana), with many populations in large reserves. Overall density estimated at one pair/50 ha in Transvaal. In Malawi, now only really common within protected areas. If some discrete races or populations prove to be full species, as in W Africa, their smaller ranges may make them more vulnerable; nevertheless, race ruahae is common in Ruaha National Park and also present in Katavi National Park. Trade is potentially under-appreciated, but perhaps not yet significant, threat. The effects of climate change might prove potentially severe over the next half-century, especially in the N half of Africa. Generally benefits from sparse ground cover created by stocking with game or livestock, provided sufficient trees suitable for nesting remain. In South Africa, race rufirostris regularly uses artificial nestboxes, and race kempi has also shown readiness to use such artificial sites in Senegal.

    Recommended citation

    Kemp, A.C. & Kirwan, G.M. (2018). Red-billed Hornbill (Tockus erythrorhynchus). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from https://www.hbw.com/node/55892 on 21 October 2018).