Forster's Tern
(Sterna forsteri)

Summary

Picture of bird
© Glen Tepke (www.pbase.com/gtepke)
For additional photos and vocalizations, visit Dendroica. (Link opens in a new window.)

The Canadian breeding range of Forster's Tern extends from Alberta through Manitoba, as well as several isolated sites in south-western Ontario. Marshlands in the Canadian prairies host the greatest concentration of Forster’s Tern in North America, yet high turnover of colony sites in response to changing wetland conditions prevents accurate monitoring through standard surveys (McNicholl et al. 2001). Data were insufficient in 1996 to allow determination of conservation status by Committee on the Status of Endangered Wildlife in Canada (COSEWIC), and population trends remain poorly quantified. This species has been identified as a priority for conservation and/or stewardship in one or more Bird Conservation Region Strategies in Canada.

Designations

Listing of the main designations for the species
DesignationStatusDateSubspecies, population
IUCN (Global)Least Concern2012 
Wild Species (Canada)Secure2010 
Bird Conservation Region StrategyPriority Species2013 

Population status

Geographic areaStatusReliability
CanadaData DeficientData Deficient
 

Population estimate

Canada10,000 - 25,000 breeding birds
 

Distribution maps

 

Migration strategy, occurrence

Short-distance migrant

Responsibility for conservation of world population

CanadaTo be determined

Conservation and management

Although Foster’s Tern is considered sensitive to the loss of wetlands (Semenchuk 2007), its nomadic movement among breeding locations may allow it to tolerate habitat change better than some other species. Occupied colony sites are often abandoned in response to fluctuations in water level or vegetation growth, but may be recolonised once suitable nesting conditions return (McNicholl et al. 2001). High predation risks posed by ground-nesting may also be tempered by the species’ flexible breeding behaviour. The threat of contaminant-induced reproductive failure, common to other piscivorous birds, is uncertain (Weseloh 2007, McNicholl et al. 2001).

 

Bird conservation region strategies

Environment and Climate Change Canada and partners have developed Bird Conservation Region Strategies in each of Canada’s Bird Conservation Regions (BCRs). In these strategies, selected species are identified as priorities for one or more of the following reasons:

  • conservation concerns (i.e., species vulnerable due to population size, distribution, population trend, abundance, or threats)
  • stewardship responsibilities (i.e., species that typify the regional avifauna or have a large proportion of their range or population in the sub-region)
  • management concerns (i.e., species that require ongoing management because of their socio-economic importance as game species, or because of their impacts on other species or habitats)
  • other concerns (i.e., species deemed a priority by regional experts for other reasons than those listed above or because they are listed as species at risk or concern at the provincial level)

Select any of the sub-regions below to view the BCR strategy for additional details.

BCRs, marine biogeographic units, and sub-regions in which the species is listed as a priority
RegionSub-region and priority type
Boreal Taiga PlainsBoreal Taiga Plains, sub-region and priority type: Prairie and Northern Region
Lower Great Lakes/St. Lawrence PlainLower Great Lakes/St. Lawrence Plain, sub-region and priority type: Ontario Region
Northern RockiesNorthern Rockies, sub-region and priority type: Pacific and Yukon Region
Prairie PotholesPrairie Potholes, sub-region and priority type: Prairie and Northern Region
 

References

  • McNicholl, M.K., P.E. Lowther, and J.A. Hall. 2001. Forster's Tern (Sterna forsteri), The Birds of North America Online (A. Poole, Ed.). Cornell Lab of Ornithology, Ithaca, New York. McNicholl, M.K., P.E. Lowther, and J.A. Hall. 2001. Forster's Tern (Sterna forsteri), The Birds of North America Online (A. Poole, Ed.). Cornell Lab of Ornithology, Ithaca, New York. (Link)
  • Moore, D.J., D.V.C. Weseloh, J. McCracken and C.A. Friis. 2010. Forster’s Terns breeding in Ontario: Historical trends and recent surveys of eastern Lake St. Clair and Long Point. Ontario Birds 28:2-19.
  • Semenchuk, G.P. 2007. The Atlas of Breeding Birds of Alberta: A Second Look. G.P. Semenchuk, Editor. Federation of Alberta Naturalists. Edmonton, Alberta. 626 pp.
  • Weseloh, C. 2007. Forster's Tern. pp. 274-275 in: Atlas of the Breeding Birds of Ontario, 2001-2005. Cadman, M.D., D.A. Sutherland, G.G. Beck, D. Lepage and A.R. Couturier, Eds. Bird Studies Canada, Environment Canada, Ontario Field Ornithologists, Ontario Ministry of Natural Resources, and Ontario Nature, Toronto, Ontario.