Forster's Tern

Sterna forsteri

Order:
Charadriiformes
Family:
Laridae
Sections
  • Version: 2.0 — Published January 1, 2001
  • Martin K. McNicholl, Peter E. Lowther, and John A. Hall
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Forster's Tern, Abundance map
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Data provided by eBird

Forster's Tern

Sterna forsteri

Abundance

This map depicts the seasonally-averaged estimated relative abundance, defined as the expected count on a one-hour, one kilometer eBird Traveling Count conducted at the ideal time of day for detection of that species in a region.  Learn more

Relative abundance
birds per km/hr
Year-round
0.21
1.71
194.56
Breeding season
Jun 7 - Jul 13
0.21
1.71
194.56
Non-breeding season
Dec 14 - Mar 1
0.21
1.71
194.56
Pre-breeding migratory season
Mar 8 - May 31
0.21
1.71
194.56
Post-breeding migratory season
Jul 20 - Dec 7
0.21
1.71
194.56
Note: Seasonal ranges overlap and are stacked in the order above; view full range in season maps.
Seasons timeline
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Adult Forster's Tern; New Jersey, June

Adult in breeding plumage (Definitive Alternate); South Cape May Meadows, NJ.; photographer Arthur Morris

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Immature Forster's Tern, first summer; Salton Sea, CA, early August.

Juvenal/Basic I plumage. ; photographer Brian L. Sullivan

Forster's Tern is the only tern restricted almost entirely to North America throughout the year. Its highest breeding numbers are found around south-central Manitoba, northern California—southern Oregon, and the Gulf Coast. Its centers of abundance in early winter match those of its coastal breeding areas, particularly around the Virginia–North Carolina border, Galveston Bay (Texas), and near Jacksonville, Florida. Similar in appearance and ecology to several other terns, it is primarily a marsh bird, although it is also found along Atlantic, Pacific, and Gulf coasts.

A “marsh tern,” this species breeds primarily in fresh, brackish, and saltwater marshes, including marshy borders of lakes, islands, or streams. It is found more often in open, deeper portions of marshes, generally in wetlands with considerable open water and large stands of island-like vegetation and/or large mats of floating vegetation. Along the Atlantic Coast, Forster's Tern breeds in marshy portions of beach and estuarine areas. The suitability of nesting habitat is often ephemeral, varying at a given site from year to year.

Major studies on Forster's Tern have focused on its breeding ecology in Manitoba (McNicholl McNicholl 1971, McNicholl 1980c, McNicholl 1982, McNicholl 1983), feeding ecology in Minnesota (Fraser Fraser 1994a, Fraser 1997) and at San Francisco Bay, CA (Salt and Willard 1971), and vocalizations and behavior in Washington (Hall Hall 1988a, Hall 1989, Hall 1998c).

Recommended Citation

McNicholl, M. K., P. E. Lowther, and J. A. Hall (2001). Forster's Tern (Sterna forsteri), version 2.0. In The Birds of North America (A. F. Poole and F. B. Gill, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bna.595