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Location Canada, Manitoba
Central coordinates 98o 30.02' West  51o 34.86' North
IBA criteria A4i
Area 30,000 ha
Altitude 244 - 267m
Year of IBA assessment 2008

Bird Studies Canada/Nature Canada

Site description Lake St. Martin is located between Lake Manitoba and Lake Winnipeg. Water from Lake Manitoba flows to Lake St. Martin via the Fairford River, and Lake St. Martin flows into Lake Winnipeg through the Dauphin River. Not much is known about the vegetation on the islands within the lake, but they are low-lying and likely far enough offshore to provide protection from predators. The surrounding shoreline of Lake St. Martin is generally flat and often marshy.

Key Biodiversity The islands of Lake St. Martin support significant numbers of several colonial waterbird species: terns, cormorants, and pelicans. A total of 3,400 Common Tern nests were recorded at this site, representing about 3% of the estimated North American population of this species. And in 1986, 1,500 Caspian Tern nests were recorded on a reef in Lake St. Martin. This number of nests is roughly equivalent to 4.5% of the North American Caspian Tern population.

Double-crested Cormorants also occur in large numbers at this site. In 1991, 2,414 cormorant nests, or about 1.6% of the Interior cormorant population, were observed at this site. Hundreds of American White Pelicans nest here too, although a recent estimate is not available. In 1969, 670 nests were counted and if increases in the overall population of pelicans also occurred here, then the population on these islands may equal about 1% of the Canadian population of the species.

Small numbers of Great Blue Herons and Black- crowned Night-Herons breed on islands within the lake. Twenty Great Blue Heron nests were recorded on an unnamed island in 1979, and another 20 nests were recorded on Big Fisher Island in 1991. Moderate numbers of ducks and geese breed and migrate amongst the Lake St. Martin Islands, and small numbers of Forsters Terns have nested in the past in the marshes bordering Lake St. Martin. Bald Eagles have been recorded as both a breeding and a staging species - it is thought that they are attracted to the fish that spawn at the mouth of the Dauphin River.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Caspian Tern Hydroprogne caspia breeding  1986  1,500 nests  A4i  Least Concern 
Common Tern Sterna hirundo breeding  1991  3,400 nests  A4i  Least Concern 


IUCN habitat Habitat detail Extent (% of site)
Wetlands (inland) Freshwater lakes and pools  -

Land use

Land-use Extent (% of site)
fisheries/aquaculture major
unknown minor

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Lake St. Martin Islands. Downloaded from on 25/10/2016

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