Phalacrocorax carbo (White-breasted cormorant)

[= Phalacrocorax carbo] 

Witborsduiker [Afrikaans]; Ugwidi (generic term for cormorants) [Xhosa]; iWonde [Zulu]; Nkororo (generic term for cormorant) [Kwangali]; Timeletsane-botha [South Sotho]; Ngulukwani [Tsonga]; Timêlêtsane [Tswana]; aalscholver [Dutch]; Cormoran à poitrine blanche [French]; Weißbrustkormoran [German]; Corvo-marinho-de-faces-brancas [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: Phalacrocoracidae

White-breasted cormorant, Strandfontein Sewerage Works, Western Cape, South Africa. [photo Duncan Robertson ©]	White-breasted cormorant, Strandfontein Sewerage Works, Western Cape, South Africa. [photo Duncan Robertson ©]

Distribution and habitat

Occurs in patches of sub-Saharan Africa; in southern Africa it is common in Zimbabwe, much of South Africa (largely excluding the arid Kalahari) and central and western Namibia, while more scarce in northern and eastern Botswana and patches of Mozambique. It can occur in almost any aquatic habitat, such as dams, streams, rivers, estuaries and the coast.

Predators and parasites

• Predators
  • of adults
    • Arctocephalus pusillus (Cape fur seals)
  • of chicks and eggs
    • Larus dominicanus (Kelp gull)  
    • Leptoptilos crumeniferus (Marabou stork) 
    • Haliaeetus vocifer (African fish-eagle)
    • Milvus aegyptius (Yellow-billed kite)
• Parasites
  • Pasteurella multocida (Avian cholera)

Movements and migrations

Largely sedentary, although it may make movements in response to changing water levels,

Food 

It mainly eats fish, doing most of its foraging 10-200 metres from the shoreline (when foraging at sea), diving in stints of up to about 82 seconds, although considerably less in freshwater. Its jaw is adapted to handling bottom-dwelling slow-moving fish, but it may catch faster fish that live closer to the surface. Smaller fish may be swallowed underwater, but with larger fish it has to take them to shore: in one case a bird died of suffocation after attempting to swallow a large Carp. The following food items have been recorded in its diet:

• fish
  • Aconthopagrus berda (Riverbream)
  • Johnius dussumieri (Small kob)
  • Rhabdosargus sarba (Natal stumpnose)
  • Thryssa vitrirostris (Orangemouth glassnose)
  • Atherina breviceps (Cape silverside)
  • Cyprinus carpio (Carp)
  • Oreochromis mossambicus (Mozambique tilapia)
  • Myxus capensis (Freshwater mullet)
  • Mugil cephalus (Flathead mullet)
  • Trachurus trachurus (Horse mackerel)
  • Cheilodactylus fasciatus (Redfinger)
  • Pterogymnus laniarus (Panga)
• frogs
  • Xenopus laevis (Common platanna)
  • Afrana angolensis (Common river frog)'
• Phalacrocorax capensis (Cape cormorant chicks)
• crabs
• molluscs

Breeding

• Usually a monogamous, colonial nester, typically living in colonies of under 50 breeding pairs, although colonies of been recorded with over 700 breeding pairs. It is often joined by other breeding birds, such as Reed cormorants, African darters, African spoonbills, Cattle egrets and other herons.
• The nest is built in roughly a week by the female, with material collected by the male, consisting of a flat platform of sticks and twigs and feathers, sometimes with seaweed and human debris. It is typically placed at a largely predator-free site, such as an island, cliff ledge, man-made guano pile, shipwreck, pylon, pan wall or the shoreline of a dams or river.
• Egg-laying season is year-round, peaking from September-December in the Western Cape and from January-July elsewhere.
• It lays 2-5, usually 3-4 eggs, which are incubated by both sexes for about 27-28 days.
• The chicks are fed by both parents by regurgitation, leaving the nest at about 28 days old. They fledge at about 49-56 days old, becoming fully independent after another 40-50 days or so.

Threats

Not threatened, although colonies may be abandoned due to human interference and predation by feral dogs.

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.