Anastomus lamelligerus (African openbill, Openbilled stork) 

Oopbekooievaar [Afrikaans]; isiQhophamnenke [Zulu]; Etongorokofu [Kwangali]; Mukyindlopfu [Tsonga]; Afrikaanse gaper [Dutch]; Bec-ouvert africain [French]; Klaffschnabel [German]; Bico-aberto [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: Ciconiiformes > Family: Ciconiidae

Anastomus lamelligerus (African openbill, Openbilled stork)  Anastomus lamelligerus (African openbill, Openbilled stork)

African Openbill. [photo Stephen Davis ]

African openbill, Kruger National Park, South Africa. [photo Trevor Hardaker ]

Distribution and habitat

Occurs across much of sub-Saharan Africa, from Mali to Ethiopia south to South Africa. In southern Africa, it is locally common in Mozambique, Zimbabwe, eastern South Africa, northern Botswana and northern Namibia. It generally prefers wetlands, such as temporarily flooded pans, flood plains, swamps, marshes, ponds, streams, river shallows, dams, rice fields, lagoons, lake edges and intertidal flats.

Distribution of African openbill in southern Africa, based on statistical smoothing of the records from first SA Bird Atlas Project ( Animal Demography unit, University of Cape Town; smoothing by Birgit Erni and Francesca Little). Colours range from dark blue (most common) through to yellow (least common). See here for the latest distribution from the SABAP2.  

Predators and parasites

Movements and migrations

Largely resident and sedentary, although it may also undertake nomadic movements, sometimes migrating in flocks away from arid regions at the onset of the dry season.

Food 

It almost exclusively eats snails and bivalves, as its bill is specially adapted to extract the meat without even breaking the shell. It often forages alongside African sacred and Hadeda ibises, typically wading through shallow water with floating plants, probing the water and extracting a snail. Once it has done so it holds it against the ground, using its razor sharp bottom mandible to sever the muscle that connects the snail to its shell, vigorously shaking its head until the snail body is extracted and promptly swallowing; the whole process can take under 15 seconds. It struggles to open other types of molluscs (such as bivalves), either failing completely or taking at least ten minutes for to pry open the shell. Consequently it may place them in groups of roughly 50-60 on the shoreline, waiting for the sun to kill them so that they release their hold on the shell. The following food items have been recorded in its diet:

  • snails
    • Bellamyia unicolor
    • Pila
    • land snails
      • Limicolaria martensiana
      • Lanistes ovum
  • bivalves
    • Coelatura mossambicensis
    • Corbicula fluminali
    • Chambardia wahlbergi
    • Mutela zambesiensis
  • frogs

Breeding

  • Monogamous, breeding in colonies of under 60, rarely up to 170 pairs, with 4-20 nests per tree. It sometimes joins mixed-species colonies along with cormorants, herons, African spoonbills, African darters and storks. Each male selects a nest site and displays on it, while females move from tree to tree and attempt to approach a male's nest site. The male repeatedly drives them away, sometimes violently, but eventually he allows the female to copulate with him.
  • The nest is built by both sexes in roughly a week, consisting of a thin platform of sticks and twigs, lined with leaves, grass, sedges and other aquatic plants, such as Antelope grass (Echinochloa), reeds (Phragmites) and knotweed (Polygonum senegalense). It is typically placed in a tree or bush on an island or partially submerged area.
  • Egg-laying season is from August-May, peaking from January-March.
  • It lays 3-5 eggs, which are incubated by both sexes for about 21-30 days.
  • The chicks are fed by both parents on a diet of shelled snails, since even at 42 days old they still cannot extract the meat from the shell. They leave the nest at about 50-55 days old.

Threats

Not globally threatened, although it is now classified as Near-threatened in South Africa, largely due to pesticides added to water to control mosquito populations, habitat loss and entanglement in fishing lines.

References

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

 

 

 Contact us if you can contribute information or images to improve this page.

Birds home   Biodiversity Explorer home   Iziko home   Search