Sterna balaenarum (Damara tern) 

Damarasterretjie [Afrikaans]; Damara-stern [Dutch]; Sterne des baleiniers [French]; Damaraseeschwalbe [German]; Gaivina de Damara [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: Charadriiformes > Family: Laridae > Genus: Sterna

Sterna balaenarum (Damara tern) 

Damara tern. [photo Johann Grobbelaar ]

Distribution and habitat

Occurs along the western coast of Africa; within southern Africa it is locally common along the coast of Namibia and the Northern Cape, while scarce further south. It generally prefers arid desert shores, especially with sheltered bays and reefs, while it mainly breeds on gravel plains between dunes and on salt pans.

Distribution of Damara tern 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

Mainly an intra-African breeding migrant, breeding in southern Africa before heading north to the west African coast in the non-breeding season.

Food 

Mainly eats fish and aquatic invertebrates, doing most of its foraging over shallow water, repeatedly plunge-diving from 3-8 metres up. The following food items have been recorded in its diet:

  • Fish
    • Tylosaurus (needle fish)
    • Mugil (small mullet)
    • Engraulis encrasicolus
    • larval blennies (Blennidae)
  • Aquatic invertebrates
    • small squid

Breeding

  • Monogamous, either nesting solitarily or in loose colonies, performing a courtship display in which the male brings fish to the female.
  • The nest is a shallow scrap in gravel or a hard salt pan, sometimes sparsely lined with shell chips or small stones and typically placed in an elevated position adjacent to a large stone, tyre, ostrich track or piece of driftwood.
  • Egg-laying season is from October-June, peaking from October-December.
  • It lays a single egg, which is incubated by both sexes for 17-30, usually 18-22 days.
  • The chick is mainly brooded by the female while the male provides the food, leaving the nest after about two days then slowly travelling towards the sea. It learns to fly at about 20 days old, at which point juveniles form flocks on the beach. It is still dependent on its parents for approximately ten more weeks.

Threats

Previously considered Endangered in Namibia, it is now thought to be Near-threatened there, as its population is now somewhat stable. However it is still Endangered in South Africa, where disturbance and urbanisation have already resulted in the loss of two colonies.

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