Common white tern (Gygis alba)

Description

Common white tern fact file

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

Common white tern description

Perhaps the most elegant and delicate seabird, the common white tern, also known as the fairy or white tern, has immaculate all-white plumage ⁽²⁾. This dainty bird has a slender body with long, tapering wings, a short, deeply forked tail and a black bill, which is unique amongst terns in that it curves slightly upwards and tapers to a sharp point ^{(2) (3) (4)}. The legs are blackish with yellow webs between the toes, while the small eyes are surrounded by black rings making them appear much larger ^{(2) (3)}. Adult common white terns look alike, but the juvenile has a brownish-grey back with grey on the neck and a black mark behind the eye. This tern flies with deep, slow wingbeats in an undulating pattern, which, although appearing erratic, is extremely strong and even allows for sustained periods of hovering ^{(2) (4)}.

Also known as

angel tern, common fairy tern, common white-tern, fairy tern, white noddy, white tern.

French

Gygis blanche.

Size

Head-body length: 25 – 30 cm ⁽²⁾

Wingspan: 76 – 80 cm ⁽²⁾

Weight

92 – 139 g ⁽²⁾

Common white tern biology

The common white tern is a proficient predator of fish, which is its main prey, as well as crustaceans and squid ⁽²⁾. It spots its prey as it hovers in the wind before diving headlong into the water and seizing its target in its bill ⁽⁴⁾. It may also take flying fish in the air and is commonly seen foraging around groups of dolphins and predatory fish which drive its prey towards the surface ⁽³⁾. 

While solitary for much of the year, during the breeding season the monogamous common white tern returns to nesting colonies and form breeding pairs ⁽³⁾. Breeding birds engage in elaborate courtship displays where the male ascends at speed to great heights, followed by the female. The pair then glide and zigzag downwards before strutting together on the ground with the tail raised and the wings dropped ⁽⁴⁾. After mating, a single egg is laid on a depression of a bare branch as, unlike other terns, this species does not build a nest ^{(3) (5)}. This nest site is aggressively defended from other birds, and intruders are viciously repelled by bill grappling and jabbing ⁽³⁾. Both the male and female share the incubation duties and soon after hatching, the chicks, which have well developed feet, toes and claws, start exploring the surrounding area ^{(3) (4)}. After fledging, the young birds stay with the parents to be fed and learn how to catch prey before becoming fully independent ⁽⁴⁾. 

Common white tern range

A widespread seabird, the common white tern inhabits islands in the tropical and subtropical waters of the south Atlantic Ocean, Indian Ocean and western and central Pacific ^{(3) (5)}.

Common white tern habitat

The common white tern breeds on small islands made of coral with some degree of vegetation, where it nests in trees and bushes, and forages over deep ocean waters ^{(2) (3) (5)}.

Common white tern status

Classified as Least Concern (LC) on the IUCN Red List ⁽¹⁾.

Common white tern threats

Although not currently at risk of extinction, the common white tern is threatened by predation from rats and cats, which have been introduced onto some islands upon which it breeds. As a result of this threat, some populations have declined while others have been lost completely. However, the common white tern has benefited on some remote islands areas from human occupation, such as on Midway Aoll where the introduction of trees and building construction increased the amount of nesting habitat available to the species. Similarly, a breeding population was established on Tern Island after the island’s vegetation was altered and buildings were constructed. The adaptable nature of this species has also allowed it to recover from past declines as it can feed on a variety of food types and reproduce quickly ⁽³⁾.    

Common white tern conservation

The common white tern is not currently the target of any specific conservation measures, but it is found in a number of protected areas. It occupies a number of reserves in the Seychelles, while most of its colonies within the Hawaiian archipelago are protected by national reserves ⁽³⁾. It has also benefited from conservation efforts to remove invasive predators on Rose, Kure and Midway Atolls and Pitcairn Island ^{(3) (6)}.  

ARKive is supported by OTEP, a joint programme of funding from the UK FCO and DFID which provides support to address priority environmental issues in the Overseas Territories, and Defra

Find out more

To find out more about bird conservation, see:

• BirdLife International:
  http://www.birdlife.org/
• The Royal Society for the Protection of Birds:
  http://www.rspb.org.uk/
• The American Bird Conservancy:
  http://www.abcbirds.org/

Authentication

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

Glossary

Crustaceans

Diverse group of animals 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, slaters, woodlice and barnacles.

Incubation

The act of incubating eggs, that is, keeping them warm so that development is possible.

Monogamous

Having only one mate during a breeding season, or throughout the breeding life of a pair.

References

1. IUCN Red List (July, 2010)
   http://www.iucnredlist.org/
2. del Hoyo, J., Elliott, A. and Sargatal, J. (2001) Handbook of the Birds of the World. Volume 3: Hoatzin to Auks. Lynx Edicions, Barcelona.
3. Niethammer, K.R. and Patrick. L.B. (1998) White Tern (Gygis alba). Cornell Lab of Ornithology. The Birds of North America Online.
4. Perrins, C. (2009) The Encyclopedia of Birds. Oxford University Press, Oxford.
5. BirdLife International (July, 2010)
   http://www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid=3298&m=0
6. Procter, D. and Fleming, L.V (1999) Biodiversity: the UK Overseas Territories. Joint Nature Conservation Committee, Peterborough, UK. Available at:
   http://www.jncc.gov.uk/page-3045%23download