Bucorvus leadbeateri (Southern ground-Hornbill)

Bromvoël [Afrikaans]; Intsingizi, Intsikizi [Xhosa]; iNgududu, iNsingizi [Zulu]; Dendera [Shona]; Insingizi, Ingududu [Swazi]; Nghututu [Tsonga]; Lehututu [Tswana]; Zuidelijke hoornraaf Southern, African [Dutch]; Bucorve du Sud [French]; Hornrabe [German]; Calau-gigante [Portuguese]

Life > Eukaryotes > Opisthokonta > Metazoa (animals) > Bilateria > Deuterostomia > Chordata > Craniata > Vertebrata (vertebrates)  > Gnathostomata (jawed vertebrates) > Teleostomi (teleost fish) > Osteichthyes (bony fish) > Class: Sarcopterygii (lobe-finned fish) > Stegocephalia (terrestrial vertebrates) > Tetrapoda (four-legged vertebrates) > Reptiliomorpha > Amniota > Reptilia (reptiles) > Romeriida > Diapsida > Archosauromorpha > Archosauria > Dinosauria (dinosaurs) > Saurischia > Theropoda (bipedal predatory dinosaurs) > Coelurosauria > Maniraptora > Aves (birds) > Order: Bucerotiformes > Family: Bucorvidae

Southern ground-hornbill. [photo H. Robertson, Iziko ©]

Southern ground-hornbills mating. [photo Arno Meintjes ©]

The Southern ground-hornbill occurs from Kenya and the DRC to southern Africa, where it is widespread but never common, living in a wide range of grassland, savanna woodland habitats. In South Africa, it is listed as Vulnerable, with an estimated population of just 1500-2000. It eats a wide range of food, especially animals, such as grasshoppers, frogs, mongooses and bird nestlings. It is a monogamous, cooperative breeder, with a group consisting of a dominant breeding pair and 0-9 helpers, who are usually either adult males, or juveniles from previous breeding seasons. It lays 1-2 eggs, which hatch in the sequence laid, meaning that the one chick is 3-14 days older than the other chick. The younger chick is unable to compete for food with its older sibling, and dies of starvation when it is 1, rarely 3-4 weeks old

Distribution and habitat

The Southern ground-hornbill occurs from Kenya and the DRC to southern Africa, where it is widespread but fairly scarce in Botswana, Zimbabwe, Mozambique, KwaZulu-Natal, Eastern Cape, Limpopo Province and northern Namibia. It generally prefers grassland and savanna woodland habitats, ranging from montane grassland to extensive, tall stands of Zambezi teak (Baikiaea plurijaga), Mopane (Colospermum mopane) and Musasa (Brachystegia spiciformis) woodlands with sparse understorey.

Food 

Mainly eats animals, such as insects, frogs, mongooses and bird nestlings. It forages in groups, so that when one bird locates a prey item it can signal the rest of the flock with a low bark.  It often finds prey by digging, especially in dung heaps, and it may snatch food from birds of prey. The following food items have been recorded in its diet:

• Animals
  • Vertebrates
    • reptiles
      • snakes (Serpentes)
      • lizards
      • chameleons (Chamaeleonidae)
      • tortoises (Testudinidae)
      • turtles (Cheloniidae)
    • mammals
      • mongooses
      • squirrels
      • young hares
    • birds
      • Quelea quelea (Red-billed quelea) nestlings
      • other birds
    • amphibians
      • frogs
      • toads
  • Invertebrates
    • insects
      • termite alates
      • dung beetles
      • Orthoptera (crickets and grasshoppers)
    • snails
  • carrion
• Plants (rarely)

Breeding

• Monogamous, cooperative breeder, with a group consisting of a dominant breeding pair and 0-9 helpers, who are either adult males or juveniles from previous breeding seasons. The group roosts in trees on rock faces, descending to the ground just before dawn and foraging for a lot of the day. They often take a break at midday to play, preen and pass around food to one another.

Southern ground hornbill in nest cavity, South Africa. [photo Arno Meintjes ©]

• The nest is usually a cavity in a tree lined with dry leaves, rarely nesting in cavities in rock faces or earthen banks. The same site is used repeatedly over many breeding seasons.
• Egg-laying season begins with the first heavy summer rains, from August-January, peaking from October-November.
• It lays 1-2, rarely 3 eggs 3-14 days apart, which are incubated solely by the female for 37-43 days. The female only makes 3-4 brief sorties out of the nest per day, so is largely reliant on the male and helpers to provide food.
• The eggs hatch in the sequence laid, meaning that the one chick is 3-14 days older than the other chick. The younger chick is unable to compete for food with its older sibling, and dies of starvation when it is about one week old, occasionally surviving for a few more weeks.. The female leaves the nest when the chick is about four weeks old, after which the chick is mostly alone in the nest. The fledging leaves the nest when it is approximately 86 days old, remaining with its parents for several years.

Threats

Vulnerable in South Africa, were it has an estimated population of just 1500-2000. Its South African distribution rang has decreased hugely recently, due to persecution and habitat alteration. Its range is also decreasing in areas of  Swaziland, Zimbabwe, Botswana and other areas of high human population density or extensive farming. However it is still widespread in areas less populated by humans, such as north-eastern Botswana and northern Zimbabwe, but it is still never common. It is generally revered by African people, but it is also feared, leading to rare cases of it being collected for "muti" for bringing rain. Current conservation measures include hand-rearing of the otherwise redundant second born chicks, captive breeding and reintroduction. For more information, visit the Endangered wildlife trust's page on the Southern ground hornbill.

References

• Hockey PAR, Dean WRJ and Ryan PG (eds) 2005. Roberts - Birds of southern Africa, VIIth ed. The Trustees of the John Voelcker Bird Book Fund, Cape Town.