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BC Conservation Data Centre: Species Summary


Hydroprogne caspia
Caspian Tern

 
Scientific Name: Hydroprogne caspia (Pallas, 1770)
Scientific Name Synonyms: Sterna caspia
English Name: Caspian Tern
 
Classification / Taxonomy
Scientific Name - Concept Reference: American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in The Auk]. Also available online: http://www.aou.org/.
Classification Level: Species
Taxonomy Comments: Jan. 2007 - changed from Sterna caspia as per NatureServe and 2006 AOU (DDW).
Species Group: Vertebrate Animal
Species Code: B-CATE
Kingdom Phylum Class Order Family
Animalia Craniata Aves Charadriiformes Laridae
   
Conservation Status / Legal Designation
Global Status: G5 (Apr 2016)
Provincial Status: S2S4B (Apr 2024)
BC List: Blue
Provincial FRPA list:   
Provincial Wildlife Act:
COSEWIC Status: Not at Risk (May 1999)
SARA Schedule:
General Status Canada: 3 - Sensitive (2005)
Migratory Bird Convention Act: Y
   
Ecology & Life History
General Description: A large stocky tern with a stout orange to coral red bill, grayish flight feathers, white underparts, and a moderately forked tail; adult has black cap in breeding season; immature and adults in basic plumage have a dusky or streaked crown; average length 53 cm, wingspan 127 cm (NGS 1983).
Global Reproduction Comments: Along the U.S. mid-Atlantic coast, nesting begins by late May or early June. Clutch size usually is 2-3. Incubation, by both sexes, lasts 20-22 days. Young are tended by both parents, leave nest in a few days, first fly at 4-5 weeks. Parental care (feeding) may extend up to 5-7 months after fledging. Nests singly or usually in colonies of up to several thousand pairs (5000+ at Sand Island, Washington).
Global Ecology Comments: Nonbreeding: often rests with flocks of other terns. At a colony at the mouth of the Columbia River, 50% of adults foraged within 8 kilometers and 90% foraged within 21 kilometers (Collis et al. 1999); at other colonies, some adults travel long distances to obtain food; up to 50 kilometers on Lake Michigan (Cuthbert and Wires 1999) and 29-60 kilometers in another reported case (Gill 1976). At expanding colonies on the Pacific Coast, birds exhibited low natal philopatry (Collis et al. 1999), but elsewhere adults show strong fidelity to colonies (Cuthbert 1988).
Migration Characteristics:
(Global / Provincial)		 
    Nonmigrant:
    Local Migrant:
    Distant Migrant:
    Within Borders Migrant: 		Y /
Y /
Y /
na /
Global Migration Comments: Juveniles in western North America disperse northward before migrating south to wintering areas, remain in wintering area through second winter, thereafter make annual migrations between breeding and wintering areas (Gill and Mewaldt 1983).

Great Lakes population winters along shores of Gulf of Mexico (Evers 1992).
Habitats:
(Type / Subtype / Dependence) 		Anthropogenic / Urban/Suburban / Facultative - frequent use
Lakes / Lake / Facultative - frequent use
Ocean / Intertidal Marine / Facultative - frequent use
Ocean / Sheltered Waters - Marine / Facultative - frequent use
Ocean / Subtidal Marine / Facultative - frequent use
Other Unique Habitats / Beach / Facultative - frequent use
Other Unique Habitats / Estuary / Facultative - frequent use
Riparian / Gravel Bar / Facultative - occasional use
Stream/River / Stream/River / Facultative - frequent use
Wetland / Marsh / Facultative - occasional use
Global Habitat Comments: Seacoasts, bays, estuaries, lakes, marshes, and rivers.

Nests on sandy or gravelly beaches and shell banks along coasts or large inland lakes; sometimes with other water birds. Pacific coast populations formerly nested mainly in inland marshes, now mainly on human-created habitats (e.g., salt pond dikes and levees) along coast; nests on dredge-spoil islands in North Carolina and Florida. See Spendelow and Patton (1988) for further details. In northeastern Lake Michigan, tended to use same colony site in successive years unless previous reproductive effort was unsuccessful (Cuthbert 1988).
Food Habits: Carnivore: Adult, Immature
Piscivore: Adult, Immature
Global Food Habits Comments: Eats mainly fishes obtained at surface of water by diving from air; sometimes feeds from surface like a gull and eats eggs and young of other terns and gulls (Terres 1980).
Global Phenology: Diurnal: Adult, Immature
Provincial Phenology:
(1st half of month/
2nd half of month)
Colonial Breeder: Y
Length(cm)/width(cm)/Weight(g): 53/ / 661
Elevation (m) (min / max): Global: 
Provincial: 
   
 
Distribution
Endemic: N
Global Range Comment: BREEDS: Eastern U.S.: locally on Atlantic and Gulf coasts, from Virginia to northern Florida (very few), also recently in New Jersey, on the central Gulf Coast of Florida, and in southeastern Louisiana, Alabama, Mississippi, and Texas; and around the Great Lakes. Canada: Labrador, southeastern Quebec, and Newfoundland; Great Lakes region in southern Ontario; southern Manitoba and central Saskatchewan, along shores of Lake Winnipeg, Lake Winnepegosis, and Dore Lake; in Lake Athabasca in northeastern Alberta; and vicinity of Great Slave Lake in southern Mackenzie. In western North America: locally (mostly in interior but on coast in Washington and California) in Washington, eastern Oregon, northern Utah, northwestern Wyoming, Idaho (recent range expansion), and North Dakota, south to southern California and western Nevada; also Baja California and Sinaloa. WINTERS: southern U.S. (mainly coastal areas north to California and North Carolina) south to Mexico; sometimes to northern South America (Colombia, Venezuela), rarely in the West Indies. Casual in Hawaii. Breeds and winters extensively also in the Old World (Africa, Eurasia, Australian region).
 
Authors / Contributors
Global Information Author: HAMMERSON, G.
Last Updated: Dec 28, 1994
Provincial Information Author:
Last Updated: Nov 27, 1998
   
References and Related Literature
American Ornithologists' Union (AOU). 1983. Check-list of North American Birds, 6th edition. Allen Press, Inc., Lawrence, Kansas. 877 pp.
Bent, A.C. 1921. Life histories of North American gulls and terns. U.S. Natl. Mus. Bull. 113. Washington, D.C.
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 Croxall et al., eds. Status and conservation of the world's seabirds. ICBP Tech. Pub. No. 2.
Byrd, M. A., and D. W. Johnston. 1991. Birds. Pages 477-537 in K. Terwilliger, coordinator. Virginia's endangered species: proceedings of a symposium. McDonald and Woodward Publ. Co., Blacksburg, Virginia.
Campbell, R.W., N.K. Dawe, I. McTaggart-Cowan, et al. 1990b. The Birds of British Columbia Vol. 2: Nonpasserines: Diurnal Birds of Prey through Woodpeckers. Royal British Columbia Museum, Victoria, BC.
Collis, K., S. Adamany, D. D. Roby, D. P. Craig, and D. E. Lyons. 1999. Avian predation on juvenile salmonids on the lower Columbia River. 1998 draft annual report submitted to Bonneville Power Administration and U.S. Army Corps of Engineers. Second Version, October 1999. Available at: www.columbiabirdresearch.org/Reports/1998_Annual_Report.pdf.
Cooper, J., A. J. Williams, and P. L. Britton. 1984. Distribution, population sizes and conservation of breeding seabirds in the Afrotropical region. Pages 403-419 in Croxall et al., eds. Status and conservation of the world's seabirds. ICBP Tech. Pub. No. 2.
Cuthbert, F. J. 1985. Mate retention in Caspian terns. Condor 87:74-78.
Cuthbert, F. J. 1988. Reproductive success and colony-site tenacity in Caspian terns. Auk 105:339-344.
Cuthbert, F. J., and L. R. Wires. 1999. Caspian Tern (STERNA CASPIA). No. 403 IN A. Poole and F. Gill, editors. The birds of North America. The Birds of North America, Inc., Philadelphia, PA. 32pp.
Evans, P. G. H. 1984b. Status and conservation of seabirds in northwest Europe (excluding Norways and the USSR). Pages 293-321 in Croxall et al., eds. Status and conservation of the world's seabirds. ICBP Tech. Pub. No. 2.
Evers, D. C. 1992. A guide to Michigan's endangered wildlife. Univ. Michigan Press, Ann Arbor. viii + 103 pp.
Feare, C. J. 1984. Seabird status and conservation in the tropical Indian Ocean. Pages 457-471 in Croxall et al., eds. Status and conservation of the world's seabirds. ICBP Tech. Pub. No. 2.
Gallagher, M. D., et al. 1984. The distribution and conservation of seabirds breeding on the coasts and islands of Iran and Arabia. Pages 421-456 in Croxall et al., eds. Status and conservation of the world's seabirds. ICBP Tech. Pub. No. 2.
Gill, R. E., Jr. 1976. Notes on the foraging of nesting Caspian terns, HYDROPROGNE CASPIA (Pallas). California Fish and Game 62:155.
Gill, R. E., Jr., and L. R. Mewaldt. 1983. Pacific coast Caspian terns: dynamics of an expanding population. Auk 100:369-381.
Harrison, C. 1978. A Field Guide to the Nests, Eggs and Nestlings of North American Birds. Collins, Cleveland, Ohio.
Hyslop, C., and J. Kennedy, editors. 1992. Bird trends: a report on results of national ornithological surveys in Canada. Number 2, Autumn 1992. Migratory Birds Conservation Division, Canadian Wildlife Service, Ottawa, Ontario. 20 pp.
Kress, S. W., E. H. Weinstein, and I. C. T. Nisbet. 1983. The status of tern populations in the northeastern United States and adjacent Canada. Colonial Waterbirds 6:84-106.
Melville, D. S. 1984. Seabirds of China and the surrounding seas. Pages 501-511 in Croxall et al., eds. Status and conservation of the world's seabirds. ICBP Tech. Pub. No. 2.
National Geographic Society (NGS). 1983. Field guide to the birds of North America. National Geographic Society, Washington, DC.
Quinn, J. S. 1984. Egg predation reduced by nest covers during research activities in a Caspian tern colony. Colonial Waterbirds 7:149-151.
Robertson, C. J. R., and B. D. Bell. 1984. Seabird status and conservation in the New Zealand region. Pages 573-586 in Croxall et al., eds. Status and conservation of the world's seabirds. ICBP Tech. Pub. No. 2.
Shugart, G. W., M. A. Fitch, and V. M. Shugart. 1981. Minimizing investigator disturbance in observational studiesof colonial birds: access to blind through tunnels. WilsonBull. 93:565-569.
Smith, G. A. 1987d. A selected and annotated bibliography for use in management of the Caspian tern (Sterna caspia). New York Dept. Environ. Conserv., Delmar, New York. 29 pp.
Spendelow, J. A. and S. R. Patton. 1988. National Atlas of Coastal Waterbird Colonies in the Contiguous United States: 1976-1982. U.S. Fish and Wildlife Service, Biological Report 88(5). x + 326 pp.
Terres, J. K. 1980. The Audubon Society encyclopedia of North American birds. Alfred A. Knopf, New York.
van Tets, G. F., and P. J. Fullagar. 1984. Status of seabirds breeding in Australia. Pages 559-571 in Croxall et al., eds. Status and conservation of the world's seabirds. ICBP Tech. Pub. No. 2.
 

Please visit the website Conservation Status Ranks for definitions of the data fields used in this summary report.

Suggested Citation:

B.C. Conservation Data Centre. 1994. Species Summary: Hydroprogne caspia. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Oct 1, 2026).