Common Tern
(Sterna hirundo)

Summary

Picture of bird
© Jukka Jantunen (flickr.com/photos/jukka_jantunen)
For additional photos and vocalizations, visit Dendroica. (Link opens in a new window.)

Common Terns are found across much of Canada, and breed primarily on freshwater and marine islands from the subarctic to the United States. The abundance of Common Terns in Canada has most likely shown little overall change relative to about 1970, though the species has decreased in abundance in the Great Lakes area and has shown decreases over the last 20 years in parts of the prairies. Competition with gulls, disruptions in the abundance of prey, and disturbance from recreational boats all adversely affect Common Terns at some breeding locations. 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
CanadaLittle ChangeMedium
 

Population estimate

Canada100,000 - 200,000 breeding birds
 

Distribution maps

 

Migration strategy, occurrence

Long-distance migrant

Responsibility for conservation of world population

CanadaLow

Conservation and management

Common Terns breeding in the Great Lakes face increasing disturbance from recreational boat traffic, but benefit from active management of habitat and predators at their colonies. At Machias Seal Island, New Brunswick (once the largest tern colony in the Gulf of Maine), terns have suffered near complete reproductive failure since 2003, and have largely deserted the colony since 2006. This dramatic decline in breeding success and abundance was associated with a switch in the diet fed to chicks, from herring to lower quality diet items, and may also have been exacerbated by increased predation from Great Black-backed and Herring Gulls (Gaston et al. 2009).

 

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
Atlantic Northern ForestsAtlantic Northern Forests, sub-region and priority type: Atlantic Region - New Brunswick
Atlantic Northern ForestsAtlantic Northern Forests, sub-region and priority type: Atlantic Region - Nova Scotia
Atlantic Northern ForestsAtlantic Northern Forests, sub-region and priority type: Atlantic Region - Prince Edward Island
Atlantic Northern ForestsAtlantic Northern Forests, sub-region and priority type: Quebec Region
Boreal Hardwood TransitionBoreal Hardwood Transition, sub-region and priority type: Ontario Region
Boreal Softwood ShieldBoreal Softwood Shield, sub-region and priority type: Atlantic Region - Newfoundland and Labrador
Boreal Softwood ShieldBoreal Softwood Shield, sub-region and priority type: Prairie and Northern Region
Boreal Softwood ShieldBoreal Softwood Shield, sub-region and priority type: Quebec Region
Boreal Taiga PlainsBoreal Taiga Plains, sub-region and priority type: Prairie and Northern Region
Great BasinGreat Basin, sub-region and priority type: Pacific and Yukon Region
Gulf of St. LawrenceGulf of St. Lawrence, sub-region and priority type: Atlantic Region - New Brunswick
Gulf of St. LawrenceGulf of St. Lawrence, sub-region and priority type: Atlantic Region - Newfoundland and Labrador
Gulf of St. LawrenceGulf of St. Lawrence, sub-region and priority type: Atlantic Region - Nova Scotia
Gulf of St. LawrenceGulf of St. Lawrence, sub-region and priority type: Atlantic Region - Prince Edward Island
Lower Great Lakes/St. Lawrence PlainLower Great Lakes/St. Lawrence Plain, sub-region and priority type: Ontario Region
Lower Great Lakes/St. Lawrence PlainLower Great Lakes/St. Lawrence Plain, sub-region and priority type: Quebec Region
Newfoundland and Labrador Shelves Newfoundland and Labrador Shelves , sub-region and priority type: Atlantic Region - Newfoundland and Labrador
Northern Pacific RainforestNorthern Pacific Rainforest, sub-region and priority type: Pacific and Yukon Region
Prairie PotholesPrairie Potholes, sub-region and priority type: Prairie and Northern Region
Scotian ShelfScotian Shelf, sub-region and priority type: Atlantic Region - New Brunswick
Scotian ShelfScotian Shelf, sub-region and priority type: Atlantic Region - Nova Scotia
Taiga Shield and Hudson PlainsTaiga Shield and Hudson Plains, sub-region and priority type: Atlantic Region - Newfoundland and Labrador
Taiga Shield and Hudson PlainsTaiga Shield and Hudson Plains, sub-region and priority type: Prairie and Northern Region
 

References

  • Courtney, P.A and H. Blokpoel. 1983. Distribution and numbers of Common Terns on the lower Great Lakes during 1900-1980: A review. Colonial Waterbirds 6:107-120.
  • Gaston, A.J., D.F. Bertram, A.W. Boyne, J.W. Chardine, G. Davoren, A.W. Diamond, A. Hedd, W.A. Montevecchi, J.M. Hipfner, M.J.F. Lemon, M.L. Mallory, J.-F. Rail and G.J. Robertson. 2009. Changes in Canadian seabird populations and ecology since 1970 in relation to changes in oceanography and food webs. Environmental Reviews 17:267-286.
  • Morris, R.D., C. Pekarik and D.J. Moore. 2012. Current status and abundance trends of Common Terns breeding at known coastal and inland nesting regions in Canada. Waterbirds 35: 194-207.
  • Morris, R.D., D.V. Weseloh, F.J. Cuthbert, C. Pekarik, L.R. Wires and L. Harper. 2010. Distribution and abundance of nesting Common and Caspian Terns on the North American Great Lakes, 1976 to 1999. Journal of Great Lakes Research 36:44-56.
  • Wilson, S., R. Bazin, W. Calvert, T.J. Doyle, S.D. Earsom, S.A. Oswald, and J.M. Arnold. 2014. Abundance and trends of colonial waterbirds on the Large Lakes of Southern Manitoba. Waterbirds 37(3):233-244. Wilson, S., R. Bazin, W. Calvert, T.J. Doyle, S.D. Earsom, S.A. Oswald, and J.M. Arnold. 2014. Abundance and trends of colonial waterbirds on the Large Lakes of Southern Manitoba. Waterbirds 37(3):233-244. (Link)