Sterna dougallii (Roseate tern) 

Rooiborssterretjie [Afrikaans]; Dougall-stern [Dutch]; Sterne de Dougall [French]; Rosenseeschwalbe [German]; Gaivina-rósea [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 dougallii (Roseate tern) 

Roseate tern. [photo Johann Grobbelaar ©]

Distribution and habitat

Occurs along the Atlantic coasts of North America and western Europe, as well as in Arabia, Australia, Asia, southern Madagascar and the coastline of mainland Africa, largely excluding the west coast. It is uncommon and localised in southern Africa, with the largest breeding population on Bird Island in Algoa Bay, Eastern Cape, with an even smaller colony on Dyer Island off the western Cape. It generally prefers coastal and marine areas, typically breeding on offshore islands and roosting there as well, or on sandbanks and rocky outcrops at a river mouth.

Distribution of Roseate 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

Its eggs are eaten by Larus dominicanus (Kelp gull).

Movements and migrations

Largely resident in southern Africa, although when the breeding season finishes in October, it tends to disperse across the coast adjacent to the island, heading back to breed again in May.

Food 

Mainly eats fish, doing most of its foraging in flocks of 20-100, often in association with other birds, such as African penguins, gulls and other terns, catching most of its prey by plunge-diving. The following food items have been recorded in its diet:

  • Fish
    • sandfish (Gonorhynchidae)
    • fingerfins (Cheilodactylidae)
    • bathyclupeids (Clupeidae)
    • elf (Pomatomidae)
    • kingfishes (Carangidae)
    • barracudas (Sphyraenidae)

Breeding

  • Monogamous, with a colony of less than 20 pairs at Dyer Island, Western Cape and one with over 240 pairs at Bird Island, Eastern Cape. It performs a spectacular courtship display in which both sexes ascend high in the sky before gliding down back to the ground.
  • The nest is a shallow scrape in the ground, usually surrounded by vegetation and sometimes lined with plant and animal debris.
  • Egg-laying season is from June to early July.
  • It lays 1-2 eggs, which are incubated by both sexes for about 25 days.
  • The chicks leave the nest at about 7-12 days old, taking their first flight at 23-28 days old and becoming fully independent 20 days later.

Threats

Not globally threatened, but Endangered in South Africa, as its population dramatically decreased in the country from the 1930's to 1970's, although since then it has been on the increase. The predation of eggs by Kelp gulls is though to be having a significant affect on breeding success.

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