Lake St. Martin Islands (MB083)
Fairford, Manitoba
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.
Birds
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. 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 3.0% of the North American Caspian Tern population.
Double-crested Cormorants also occur in large numbers at this site. In 2012, 3,169 cormorant nests were observed. Hundreds of American White Pelicans have nested here too, 670 nests being recorded in 1969. Gulls also nest on these islands. An estimated 3,765 Ring-billed Gull nests were recorded in 2012. These breeding birds were split over three colonies across the lake. 53 Herring Gull nests were noted during the same survey.
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 the lake. 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.
Conservation Issues
Given that the numerous waterbirds that breed here consume fish as a large part of their diets, it is possible that local fishermen may not support the conservation of these birds. Although these bird species are known to largely eat non-game species, in some locations fisherman perceive these birds as threats to local fish stocks and occasionally illegally kill many cormorants, and in some cases herons and possibly terns.
This is traditional land for three First Nations (Lake St Martin First Nation, Pinaymootang First Nation and Little Saskatchewan First Nation), but this site is not well known by ornithologists and more bird surveys are needed.
Following flooding in 2011, water was diverted from the Assiniboine River into Lake Manitoba and then into Lake St Martin resulting in flooding of surrounding communities and land. Water is now regulated in Lake St Martin by the Fairford River Control Structure and the Lake St. Martin Emergency Channel. In the long-term it is unknown how these changes may impact on bird populations and movements across the lake.
IBA Criteria Habitats Land Uses Potential or Ongoing Threats Conservation Status
