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Sooty Tern Sterna fuscata fuscata 


Sooty Tern

At a glance

A pelagic tern with a dark back and white underparts.

Occurs in tropical seas worldwide.

Will not land on water. Pelagic sub-adults stay on the wing for years at a time (6-10 years), never resting and ‘sleeping’ while in flight

Three quarters of all the seabirds nesting in the West Indies are Sooty Terns.

THE egg bird of the West Indies.

Index


Identification:

Except for Bridled Terns all other black terns are have dark ventral surfaces (although adult male Black Terns have white under-wings). Sooty Terns are larger (43-45 cm (17-18 inches) total length) than Bridled Terns, their white forehead extends only back to the eye, and they lack a white collar.

Adults

Age of first breeding 4-10 years. Known to live for up to 34 years. Black dorsally with white breast, necks, under wings and tail, and forehead. Similar appearing adult Bridled Terns have white cervical collar.

Juveniles

Immature Sooty Terns tend to be sooty brown (appear black) with white spotting on upper wing, have all black heads, and in their second to adult years have variably dark heads, necks and upper breasts. Once they leave their nesting islands most young Sooty Terns live in the eastern south Atlantic until they achieve adult plumage.

Alternative Names

English: Wideawake

French: Sterne fuligineuse

Spanish: Charrdon sombrio

Systematics

One of four species of dark-backed, pelagic Sterna, three of which are tropical. In the past, the tropical species have been placed from time to time in other genera. Seven subspecies are recognized; the nominate is the only one occurring in the Atlantic.

Likely locations

Except at nesting sites and after tropical storms seldom seen from land, species is highly pelagic.

Distribution

This tern occurs throughout the world's tropical seas.

Regional population breeds throughout the Bahamas and Greater and Lesser Antilles, also on US coast, North Carolina (sporadic), Florida Keys, Louisiana and Texas coasts. Additional colonies are known from the Caribbean coastal cays of Mexico and islands off the coast of northern South America. Outside this region, species also breeds on a number of tropical Atlantic oceanic islands.

Young sooty terns from the Western North Atlantic live primarily off the west coast of Africa. Adults are largely confined to the tropical seas of our region and, in summer, a few wander north through the Gulf Stream. 

sote terns

Biology

At sea

Pelagic: high-flying and frequently in large flocks, sometimes thousands of birds are in a single flock. Feeding flocks, often mixed with other species of pelagic birds, form over foraging surface feeding fishes (frequently schools of tuna). Hunts from 1-20 meters above surface descending as prey nears surface. Catches prey by aerial dipping and contact dipping. Main foods are small pelagic fishes and squid. Does not land on water as development of uropygial gland does not provide for proper oiling of feathers during preening.

At the nest

Vocalizing adults swarm over nesting islands at night for months prior to nest construction. Can arrive as early as February, but most appear in late April and May. Nest in both open and vegetated sites depending on location. Nest is a simple scrape. Single, pale, speckled egg. Average incubation 30 days. Fledge in about 8 weeks (dependent on food availability). Remain in colony another half-month and are fed by parents. Parents probably continue to feed fledglings at sea over the following 2-3 months. Young birds return to nesting sites as breeding adults in 4 to 10 years.

Current Population 

Country Breeding Sites Low Estimate High Estimate
United States (Dry Tortugas)44000040000
Bahamas 62 21431 22885
Turks and Caicos 7 48315 48405
Cuba 9 2696 2714
Jamaica 8 71100 85500
Dominican Republic 4 130001 130110
Puerto Rico 10 40510 40600
US Virgin Islands 9 30354 40835
Anguilla 5 30332 52446
St. Bartholomew 1 150 300
Saba 1 15 30
St. Christopher and Nevis 1 200 250
Antigua and Barbuda 5 514 519
Guadeloupe 9 4947 5847
Dominica 3 2 20
Martinique 5 6030 8796
St. Lucia 2 33280 43280
St. Vincent and the Grenadines 4 1565 3565
Grenada 7 6 510
Trinidad and Tobago 6 2800 4100
Venezuela 7 10010 12325
Aruba 1 6650 6650
Colombia 2 100 1000
Total 172 481008 550687


Southeastern United States: Single large nesting colony at Dry Tortugas, but small groups and individual pairs occasionally nest along Gulf Coast and north to the Outer Banks: 40,000 pairs (Clapp and Buckley 1984); Bahamas: 4,000-8,000 pairs (Salvia 2000); West Indies: 200,000-300,000 pairs (Salvia 2000); Islands off Central America: ca 1,000s (van Halewyn and Norton 1984); Islands off South America 30,000+ (van Halewyn and Norton 1984). Greater Caribbean: Total 230,000-500,000+ pairs. (Sylva 2000; van Halewyn and Norton 1984)


Kushlan et al. (2003) estimate 3,360,000-4,380,000 (1,680,000-2,190,000 pairs) Sooty Terns in the Americas. This figure includes breeding colonies in portions of the tropical Pacific. While this is the most common seabird nesting in the West Indies the region’s colonies are small in comparison to some in the Indian Ocean where single colonies many have hundreds of thousands of nests. The global population (probably also the entire galaxy) is estimated to be 18-23 million pairs (Schreiber et al. 2002).

Conservation Status

This is the most abundant seabird breeding in the tropical Atlantic. Many of its nesting colonies are protected and it is not a species of conservation concern.

Conservation Needs

Because of the size of some of the larger colonies this became THE egg bird of the region. Egging is done on both subsistence and commercial scales and continues today in many places throughout the West Indies where colonies have little or no protection. Many still believe that seabird and marine turtle eggs possess aphrodisiac qualities. At least in the past when large numbers of eggs were collected, people would go through entire colonies stepping on all the eggs, and then later return and collect the eggs knowing they were fresh and of market quality. All colonies of Sooty Terns with more than a few hundred pairs need constant surveillance during the peak nesting periods.

Despite the species abundance, it is in need of protection. The majority of birds nest in 13 colonies of 1,000 or more pairs. These sites should all be off limits to visitation during the breeding season and given whatever levels of protection are necessary. Exotic predator control may be necessary at some sites, and vegetation management should be considered on a site-by-site basis. Several of the really large colonies (10,000 or more pairs) would benefit from seasonal wardens being stationed at the sites.

Feral dogs and cats are the biggest threat to regional colonies and attempts should be made to eradicate them from breeding sites. As in many seabird colonies, black and Norway rats can be significant factors in the loss of eggs and chicks. The introduced red fire ant is also reported to have negative impact on colony success. Individual Laughing Gulls that are seen making a living patrolling tern colonies for eggs and chicks should be eliminated.

Species has been well studied within in the region (Florida Keys, Puerto Rico). Seminal annual census of the large colonies is needed to insure stability. Many sites have not been surveyed for decades. The West Indies region is dotted with small rocks and cays with <100 pairs of nesting Sooty Terns. While individually less important than the larger colony sites, collectively these smaller sites represent a significant portion of the total population. These sites need to be identified and periodically monitored. In some cases posting these colonies would be beneficial but many are in existence because they are on rocks that are not assessable by boat. Others are isolated and seldom visited.

Education and enforcement programs need to stepped-up throughout the region.

Photos

Selected References:

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.

Robertson, W. W. Jr. 1964. The terns of the Dry Tortugas. Bull. Fla. State Museum Biological Sciences. 8: 1-95.

Saliva, J. E. 2000. Conservation priorities for Sooty Terns in the West Indies. Pages 103-108 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.

Schreiber, E. A., C. J. Feare, B. A. Harrington, B. G. Murray, Jr., W. B. Robertson, Jr., M. J. Robertson, and G. E. Woolfenden. 2002. Sooty Tern (Sterna fuscata). In The Birds of North America, No. 665 (A Poole and F. Gill, eds.). The Birds of North America, Inc. Philadelphia, PA.

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.

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. 2008. Sooty Tern. West Indian Breeding Seabird Atlas <http://www.wicbirds.net/sote.html>. Last Updated: _____. Date accessed: ______.

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