Sandwich Tern

Sandwich Tern

Sterna sandvicensis

Charrßn de Sandwich,
Gaviota de Pico Agudo

Photo: B. Hallett

IDENTIFICATION: Smaller than the Royal Tern, the Sandwich Tern is a medium-sized white seabird with very light gray upper parts. It has a black bill with a contrasting, yellow tip. It has a black cap in breeding season, but the black is limited to the back of the head most of the year. Unlike many medium-sized terns, its legs and feet are black. Length: 38 cm.; weight: 170-210 g.

VOICE: A harsh, two-note call. Audio (M. Oberle).

HABITAT: Coastal marine waters; nests on isolated sandbars and islands.

HABITS: The Sandwich Tern dives for small fish, shrimp, squid, and marine worms. Both sexes scrape a nest on a sandy or shell-covered beach in a nesting colony, often near Royal Terns. Both sexes incubate a single egg (occasionally two) and feed the young. Laughing Gulls, Oystercatchers (Haematopus palliatus), and Ruddy Turnstones (Arenaria interpres) prey upon unguarded eggs. Even outside the breeding season, this species often feeds, roosts and travels with Royal Terns.

STATUS AND CONSERVATION: A locally common bird in coastal Puerto Rico. In addition to local breeding populations, migrants from North America occur in Puerto Rico. Sandwich Terns banded in North Carolina have been recovered in Puerto Rico. Nests at Culebra and some islets off La Parguera and Guayanilla, and is a regular winter visitor in San Juan harbor, Mayagüez Bay, and Boquerón Bay. The West Indian breeding population is estimated at 2,100-3,000 pairs.

RANGE: Breeds in eastern North America and a few Caribbean islands and disperses as far south as Uruguay in winter. A European population breeds from the British Isles east to the Caspian Sea.

TAXONOMY: CHARADRIIFORMES; LARIDAE; Sterninae. A yellow-billed form of this bird, the Cayenne Tern (Sterna eurygnatha, Charrßn de Cayena), has been considered a separate species by some biologists. This form has bred at Culebra since 1986 and has also bred at La Parguera. Birds with varying degrees of yellow suggest that Sandwich and Cayenne Terns may interbreed regularly. Intermediate forms with different degrees of yellow on the bill can be seen in San Juan harbor or at Puente Moscoso.

Photo: J. Saliva

Photo: A. Sßnchez Mu±oz

Photo: B. Hallett

Photo: G. Beaton

References

Bent, A.C. 1921. Life histories of North American gulls and terns. Smithsonian Instit. U.S. National Museum Bull. 113. (Reprinted by Dover Press, 1963).

del Hoyo, J., A. Elliott, and J. Sargatal, eds. 1996. Handbook of Birds of the World, Vol. 3. Hoatzin to Auks. Lynx Edicions, Barcelona.

Ehrlich, P.R., D.S. Dobkin, and D. Wheye. 1988. The birder's handbook: a field guide to the natural history of North American birds. Simon and Schuster/ Fireside, NY.

Harrison, P. 1983. Seabirds: an identification guide. Houghton Mifflin, Boston.

Harrison, P. 1987. A field guide to seabirds of the world. Stephen Greene Press, Lexington, MA.

Norton, R. L. 2000. Status and conservation of Sandwich and Cayenne Terns in the West Indies. Pp. 80-86 in Status and conservation of West Indian seabirds (E. A. Schreiber and D. S. Lee, eds.). Soc. Carib. Ornith., Special Pub. No. 1.

Quintana, F. and P. Yorio. 1997. Breeding biology of Royal and Cayenne Terns at a mixed-species colony in Patagonia. Wilson Bull. 109:650-662.

Raffaele, H.A. 1989. A guide to the birds of Puerto Rico and the Virgin Islands. Princeton.

Raffaele, H.A. 1989. Una guía a las aves de Puerto Rico y las Islas Vírgenes. Publishing Resources, Inc., Santurce, PR.

Raffaele, H.A., J.W. Wiley, O.H. Garrido, A.R. Keith, and J.I. Raffaele. 1998. Guide to the birds of the West Indies. Princeton.

Schreiber, E. A. and D. S. Lee. 2000. West Indian seabirds: a disappearing natural resource. Pp. 1-10 in Status and conservation of West Indian seabirds (E. A. Schreiber and D. S. Lee, eds.). Soc. Carib. Ornith., Special Pub. No. 1.

Schreiber, E. A. 2000. Action plan for conservation of West Indian seabirds. Pp. 182-191 in Status and conservation of West Indian seabirds (E. A. Schreiber and D. S. Lee, eds.). Soc. Carib. Ornith., Special Pub. No. 1.

Shealer, D.A. 1996. Foraging habitat use and profitability in tropical Roseate Terns and Sandwich Terns. The Auk. 113:209-217.

Shealer, D. A. 1998. Differences in diet and chick provisioning between adult roseate and sandwich terns in Puerto Rico. Condor 100(1):131-140.

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

Stienen, E. W. M. and A. Brenninkmeijer. 2002. Foraging decisions of Sandwich Terns and kleptoparasitising gulls. Auk 119(2):473-486.

Wiley, J. W. 2000. A bibliography of seabirds in the West Indies. Pp. 192-225 in Status and conservation of West Indian seabirds (E. A. Schreiber and D. S. Lee, eds.). Soc. Carib. Ornith., Special Pub. No. 1.

Sandwich Tern, Spanish text

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