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Sandwich Tern Sterna sanvichensis acuflavidus


Sandwich Tern

At a glance

Temperate-subtropical species

Coastal inshore forging

Only crested tern with a black bill

Extending breeding range southward into Caribbean over the last 30-40 years

No really large colonies in the region at this time

Index


Identification:

A medium sized (40-45 cm (16-18 inches) total length) very white tern with a dark crest. Can be distinguished from similar Atlantic terns by its all black, yellow- tipped bill. Only other adult plumaged white tern with a black bill is the Gull-billed Tern. The Gull-billed tern's bill is not slender and lacks the yellow tip. In flight the yellow tip of Sandwich Tern’s bill may not show, making the bill appear as if it has a square end. Cayenne Terns have yellow bills, legs and feet. For these and other terns in difficult to identify plumages, note the colors of the legs, feet and bills.

Adults

Begin nesting in 3rd to 4th summer. Can live to 23-24 years of age. Black crested, black billed, white tern. Legs and feet also black. Non-breeding adult with reduced cap, forehead white.
Sandwich Tern, non-breeding, photo: Dave Lee

Juveniles

Juveniles similar to adults but have gray backs, feathers tipped with brown.

Alternative Common Names

English: Cabot’s Tern

French: Sterne caugek

Spanish: Charran de sandwich, Charran de Cbot, Charran patinegro, Gaviota de pico Amarillo (Cuba), Gaviota oico agudo (Dominican Republic), Gaviota piquiaguda (Puerto Rico).

Systematics

Often placed in the genus Thalasseus with other crested terns. Two subspecies, the nominate is European, and S. s. acuflavida is the New World race. Many consider the Cayenne Tern, S. (s.) eurygaatha, of the southern Caribbean to be the third subspecies. It is treated separately here, mostly because it is simpler for us to discuss distributions and conservation issues in individual accounts.

Likely locations

At nesting colonies and near coast, does not normally feed far at sea.

Distribution

This species breeds in North America, Central America, and Eurasia. It is named after one of its European breeding sites, the Isle of Sandwich. Two subspecies are recognized one each in the Old and New World, another known as the Cayenne Tern, is not common and is restricted to the coast of South America and the lower Caribbean. Many consider it to be a separate species (see that account)

Breeds in New World from Virginia southward and along the Gulf coast. Also breeds in West Indies, islands and off Central America. This is a coastal foraging species and excluding migration periods it is almost never seen more than 20 km from land.

Biology

At sea

Feeds along coast and in bays. Seldom more than 2 km from land. Roost at night on sand bars, beaches and reefs. Prey items fishes, squid, and crustaceans. In Puerto Rico feeds mainly on sardines and dwarf herring. Vertical dives from 5-7 meters into water. In shallow water dives are at acute angels, sometimes from hovering flight. Will follow trawlers for discarded fish and diving pelicans for fish that are stirred up by the foraging pelicans.

At the nest

The first colony in the West Indies was found in 1965. Breeding colonies begin to form in late April and early May. Nest a simple scrape, sometimes lined with pieces of shell or wrack. Generally lays only one egg, occasionally two. Eggs are pale with variable markings. Incubation 21-29 days. Chicks move away from nest in first 2-3 weeks after hatching and form crèche, will leave nest earlier if subject to disturbance. First flight 25-28 days, dispersal from colonies soon after young are fledged. Colonies vacant by late August and early September. Young accompany adults to near by feeding areas. Total time adults spend in nesting colonies (pre-laying to post nesting dispersal) is about 52 days. Colony size fluctuates, in Puerto Rico between 23 and 450 pairs from 1990-1994.

Current Population

New World Sandwich Tern, Sterna s. sandvicensis

Area Breeding Pairs Source
Central Atlantic States (Virginia) 140 Buckley and Buckley 1984
Southeastern US 44805 Clapp and Buckley 1984
Central America (islands off coast) 100s van Halewyn and Norton 1984
West Indies 2100-3000 Norton 2000
North America Total 48000 (37500-50000) Kushlan et al. 2002

Conservation Status

This is not a species of conservation concern in the West Indies. Formerly in western Caribbean off Belize but now extirpated there. Also recently extirpated from several cays in US and British Virgin Islands.

Conservation Needs

In that this species has been extending its range southward from coastal North America into the West Indies for the last 30-40 years, this tern cannot be considered a conservation priority. Nonetheless, colonies disserve protection, and at many sites these terns are nesting with, or adjacent to, seabirds with conservation needs. Like other seabirds, colonies of Sandwich Terns need protection from development, disturbance, and introduced predators. Closing nesting cays from visitation during the breeding season should be encouraged. Laws prohibiting egging need to be enforced.

Genetic studies to determine the relationship of Sandwich Terns to Cayenne Terns are needed.

Selected References:

Buckley, P. A. and F. G. Buckley. 1984. Seabirds of the North and Middle Atlantic coast of the United States: their status and conservation. Pages 101-133 in J. P. Croxall, P. G. Evans and R. W. Schreiber (eds.). Status and Conservation of the World's Seabirds. ICBP Tech. Publ., No. 2. 778 p.

Clapp, R. B. and P. A. Buckley. 1984. Status and conservation of seabirds in the southeastern United States. Pages 135-155 in J. P. Croxall, P. G. Evans and R. W. Schreiber (eds). Status and Conservation of the World's Seabirds. ICBP Tech. Publ., No. 2. 778 p.

Kushlan, J. A., et al. 2002. Waterbird Conservation for the Americas: the North American Waterbird Conservation Plan, Version 1. Waterbird Conservation for the Americas, Washington, DC, USA., 78 pp.

Norton, R. L. 2000. Status and conservation of Sandwich and Cayenne Terns in the West Indies. Pages 80-83 in E. A. Schreiber and D. S. Lee (eds.) Status and Conservation of West Indian Seabirds. Society of Caribbean Ornithology, Special Publication Number 1.225 pp.

Shealer, D. 1999. Sandwich Tern (Sterna sandvicensis). in The Birds of North America, No. 405 (A. Poole and F. Gill. Eds.). The Birds of North America, Inc., Philadelphia.

van Halewyn, R. and R. Norton. 1984.The status and conservation of seabirds in the Caribbean. Pages 169-222 in J. P. Croxall, P. G. Evans and R. W. Schreiber (eds). Status and Conservation of the World's Seabirds. ICBP Tech. Publ., No. 2. 778 p.

West Indian Breeding Seabird Atlas by Will Mackin and David Lee is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 United States License. Based on work at www.wicbirds.net. Permissions beyond the scope of this license may be available at www.wicbirds.net.

Suggested Citation: Lee, D. S., W. A. Mackin. 2009. Sandwich Tern. West Indian Breeding Seabird Atlas <http://www.wicbirds.net/sate.html>. Last Updated: _____. Date accessed:_________.

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