Phalacrocorax neglectus (Bank cormorant)

Bankduiker [Afrikaans]; Kustaalscholver [Dutch]; Cormoran des bancs [French]; Küstenscharbe [German]; Corvo-marinho-dos-baixios [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

Bank cormorant, Kommetjie, South Africa. [photo Trevor Hardaker ©]

Distribution and habitat

Endemic to southern Africa's western coast, from Namibia down to the Northern and Western Cape. It generally stays close to the coastline, especially within the kelp zone, rarely moving further out to sea.

Predators and parasites

• Predators
  • Orcinus orca (Killer whale)
• Parasites
  • conjunctivitis caused by Staphylococcus and Haemophilus.

Movements and migrations

Adults generally stay within roughly 10 km of their breeding site, although juveniles disperse and travel much longer distances after fledging.

Food 

It eats fish and aquatic invertebrates, doing most of its foraging alone among kelp beds, descending to the sea floor to catch slow-moving bottom-dwellers. It dives in stints of 26-80 seconds, often descending to a depth of at least 28 metres. The following food items have been recorded in its diet:

• Fish
  • Sufflogobius bibarbatus (Pelagic goby)
  • Merluccius (hakes)
  • Cancelloxus burrelli (Slender platanna klipfish)
  • Gnathophis capensis (Southern conger)
  • Chorisochismus dentex (Rock sucker)
  • Gonorhynchus gonorhynchus (Beaked sandfish)
  • Syngnathus acus (Southern conger)
  • Sepia vermiculata (Common cuttlefish)
  • flatfish
• Invertebrates
  • Pterygosquilla armata (Cape mantis shrimp)
  • Octopus (octopus)
  • Jasus lalandii (West coast rock lobster)
  • Plagusia chabrus (Cape rock crab)
  • Parechinus angulosus (Cape urchins)
  • Haliotis (abalones)
    • H. parva
    • H. middae
    • H. chitons

Breeding

• Monogamous, typically nesting in colonies of 20-100 pairs, with the male performing a display in which he throws head forward and backward repeatedly.
• The nest is built by both sexes (see image below), consisting of a large platform built largely of fresh seaweed with a few sticks and feathers. It is typically placed on coastal islands, cliffs, boulders, walls, inshore rocks or artificial platforms next to the sea.

Adult on nest. [photos H. Robertson, Iziko ©]

• Egg-laying season is year-round, peaking from May-October in the Western Cape and from November-April in Namibia.
• It lays 1-3 eggs, which are incubated by both sexes for about 28-32 days.
• The chicks start exploring the area around the nest at about 50 days old, taking their first flight at 55-70 days old and becoming fully independent roughly three months later.

Threats

Previously classified as Vulnerable, its status has since worsened to Endangered, as its population has decreased by at least 50% in the last three generations. Its largest colony (on Ichaboe Island, Namibia) is contracting in size due to a collapse in the stocks of Pelagic goby (Sufflogobius pusillus). This combined with general food scarcity, human disturbance and competition for space with Cape fur seals (Arctocephalus pusillus) has been responsible for decreases in population on other islands and breeding sites.

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.