Mycteria ibis (Yellow-billed stork)

Nimmersat [Afrikaans]; Nepando [Kwangali]; Mokotatsie (also applied to White stork) [South Sotho]; Afrikaanse nimmerzat [Dutch]; Tantale ibis [French]; Nimmersatt [German]; Cegonha-de-bico-amarelo [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

Yellow-billed stork, Spitskop Dam, South Africa. [photo Trevor Hardaker ©]	Top right: Yellow-billed stork. [photo Johann Grobbelaar ©] Bottom right: Yellow-billed stork. [photo Jeff Poklen ©]

Distribution and habitat

Occurs across much of sub-Saharan Africa. In southern Africa it is common to locally abundant in Mozambique, Zimbabwe, the eastern half of South Africa, northern and eastern Botswana and Namibia (including the Caprivi Strip). It generally prefers wetlands, such as pans, flood plains, marshes, streams, flooded grassland and small pools, occasionally moving into mudflats and estuaries.

Predators and parasites

• Predators
  • of adults
    • Crocodylus niloticus (Nile crocodile)
  • of eggs
    • Haliaeetus vocifer (African fish-eagle)

Movements and migrations

Largely resident and nomadic, moving in response to fish availability and water levels. Its numbers peak from October-April in Mozambique, Zimbabwe, Botswana and Namibia, suggesting that it might be an intra-African breeding migrant.

Food 

It mainly eats fish, doing most of its foraging in shallow water without vegetation, often wading with its bill half open and immersed in the water while stirring up mud with its feet, catching any flushed by snapping its bill shut. It may also follow Nile crocodiles (Crocodylus niloticus) or Hippopotamuses (Hippopotamus amphibius), catching the animals they disturb. The following food items have been recorded in its diet:

• Vertebrates
  • fish
  • frogs
    • Pyxicephalus adspersus (Giant bullfrog)
• Invertebrates
  • aquatic insects
  • worms
  • crustaceans

Breeding

• Monogamous, breeding in colonies of 10-20, sometimes up to 50 nests per tree, often alongside ibises, herons, African darters, other storks (especially Marabou storks), African spoonbills and/or cormorants.
• The nest is built by both sexes in about 7-10 days, consisting of a platform of sticks with a shallow central cup lined with leaves, fine grass, reeds and aquatic grasses. It is typically placed on top of a tree, such as Acacia, Water fig (Ficus verruculosa) or Baobab (Adansonia digitata), roughly 3-7 metres above ground or water.
• Egg-laying season is from July-March, peaking from August-October.
• It lays 2-4 eggs, which are incubated by both sexes for roughly 30 days.
• The chicks are brooded by both parents, constantly at first but more intermittently later, while both adults provide food by regurgitation. They take their first flight at about 35 days old, leaving the nest at about 55 days old and becoming independent five days or so later, although they may return to the nest to roost up to approximately 90 days old.

Threats

Not threatened globally, although Near-threatened in South Africa due to wetland disturbance and destruction..

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.