Saunders’s tern (Sterna saundersi)

Description

Saunders’s tern fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Saunders’s tern description

A poorly known species ⁽³⁾, Saunders’s tern (Sterna saundersi), also known as the black-shafted tern ⁽²⁾, is a small bird that is easily be mistaken for the little tern (Sterna albifrons) ⁽⁴⁾.

Adult Saunders’s terns have pale grey upperparts, while the underparts, rump and tail are a contrasting white ⁽⁵⁾. The first three or four main flight feathers on the outermost parts of the wings are black, creating a striking streak along the edge of the wing when the bird is in flight ⁽⁵⁾. Its legs and feet can vary in colour, being olive, dark reddish-brown or pinkish-brown ⁽⁵⁾.

Breeding adult Saunders’s terns have a black cap. with a triangular white forehead patch reaching from the top of the beak to the front of the eye, and a yellow bill with a black tip ⁽⁵⁾. Outside of the breeding season, adults have a mostly white head, with black plumage extending from the back of the neck through the eye, and an all-black bill ⁽⁵⁾.

Juvenile Saunders’s terns have sandy buff plumage, with each feather having a darker centre ⁽⁵⁾.

Also known as

Saunders’ little tern.

French

Sterne de Saunders.

Size

Length: 20 - 28 cm ⁽²⁾

Wingspan: 50 - 55 cm ⁽²⁾

Weight

40 - 45 g ⁽²⁾

Saunders’s tern biology

Marine animals, such as small fish, crustaceans and molluscs are the favoured foods of Saunders’s tern, but it will also feed on various insects ⁽²⁾. In a flock, it may travel up to 15 kilometres offshore to feed ⁽⁴⁾, where it hovers, often for long periods of time, before diving from up to 20 metres in the air into the water to seize its prey ^{(2) (4)}. Saunders’s tern may also occasionally capture prey near the surface by simply dipping its head into the water ⁽⁴⁾.

During the breeding season Saunders’s tern forms small colonies of about five to thirty pairs ^{(2) (3)}. Each pair selects a suitable site, typically above the high-tide line or on mudflats ⁽²⁾, where small mounds of sand surrounding plants or other debris provide the perfect nest ⁽²⁾. Alternatively, a small hollow or animal footprint in the ground may be lined with small pebbles to create a suitable nest ⁽²⁾. The nest is usually placed between 20 and 100 metres apart from other nests in the colony ⁽²⁾. Each female lays two pale eggs ⁽²⁾, between February and late April ⁽⁶⁾. 

Saunders’s tern range

Saunders’s tern has a very large range. Its breeding range stretches from the Red Sea coast and Arabian Gulf, to north-west India, Sri Lanka and the Maldives ⁽³⁾.

During winter, Saunders’s terns that breed in north-east Africa migrate south, as far as Tanzania, while other populations migrate eastwards to the west coast of India, Sri Lanka, the Maldives, Seychelles and Malaysia. Populations in south-east Somalia, Sudan and Socotra appear to remain in the same area year-round ⁽³⁾.

Saunders’s tern habitat

A range of coastal areas provide habitat for Saunders’s tern, including shallow tropical and subtropical inshore waters ⁽⁴⁾, estuaries, tidal lagoons ⁽²⁾ and harbours ⁽⁴⁾. It nests up to two kilometres inland and travels up to 15 kilometres out to sea when feeding ⁽³⁾.

Saunders’s tern status

Saunders’s tern is classified as Least Concern (LC) on the IUCN Red List ⁽¹⁾.

Saunders’s tern threats

When nesting, Saunders’s term is highly vulnerable to human disturbance, and its coastal breeding habitat is threatened by development ⁽³⁾. Saunders’s tern chicks and eggs are also preyed on by rats and cats in some areas ⁽²⁾.

Saunders’s tern conservation

A frequently overlooked bird, in part due to significant difficulties in its identification, there are no known specific conservation measures in place for Saunders’s tern ⁽²⁾.

However, it does occur in a number of protected areas throughout its range. For example, some stretches of the Watamu coast, Kenya, which contain internationally important numbers of Saunders’s tern (5,700) are protected as a National Marine Park ⁽⁷⁾, and the Khawr Shumayr wetlands in Oman, protected by Royal Decree in 1994, provides internationally important habitat for Saunders’s tern ⁽⁸⁾.

View information on this species at the UNEP World Conservation Monitoring Centre.

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Find out more

Learn more about bird conservation:

• BirdLife International:
  http://www.birdlife.org/

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This species information was authored as part of the ARKive and Universities Scheme.

Glossary

Crustaceans

A diverse group of animals with jointed limbs and a hard external skeleton, characterised by the possession of two pairs of antennae, one pair of mandibles (parts of the mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps and barnacles.

Molluscs

A diverse group of invertebrates, mainly marine, that have one or all of the following; a horny, toothed ribbon in the mouth (the radula), a shell covering the upper surface of the body, and a mantle or mantle cavity with a type of gill. Includes snails, slugs, shellfish, octopuses and squid.

References

1. IUCN Red List (November, 2010)
   http://www.iucnredlist.org/
2. del Hoyo, J,. Elliot, A. and Sargatal, J. (1996) Handbook of Birds of the World. Volume 3: Hoatzin to Auks. Lynx Edicions, Barcelona.
3. BirdLife International (November, 2010)
   http://www.birdlife.org/
4. Snow, D.W and Perrins, C.M. (1998) The Birds of the Western Palearctic. Volume 1. Oxford University Press, New York.
5. World Register of Marine Species (November, 2010)
   http://www.marinespecies.org/
6. Newton, S.F. (2006) Guide to Standard Survey Methods for Seabirds. Regional Organization for the Conservation of the Red Sea and Gulf of Aden (PERSGA), Saudi Arabia. Available at:
   http://www.persga.org/Files/Common/Sea_Birds/SSM_Seabirds.pdf
7. Ramsar Sites Information Service (November, 2010)
   http://ramsar.wetlands.org/Portals/15/OMAN.pdf
8. BirdLife International – Watamu Coast (November, 2010)
   http://www.birdlife.org/datazone/sitefactsheet.php?id=6406