The Contrecoeur Islands are situated in the St. Lawrence River, approximately 75 km downstream from Montréal, near the village of Contrecoeur. There are 29 islands spread over a 10 km stretch, from Île au Dragon in the west to Île au Coeur de Pierre in the east. In spring, some islands are completely submerged. The islands are almost completely vegetated with grasses (mostly Canary Grass) and areas of emergent grass link some of the islands. Vegetation in the shallower marshes is comprised of cattails, rushes and arrowheads. A small Red Ash grove remains on one of the islands.
The Contrecoeur Islands are a globally significant breeding site for Ring-billed Gulls, with an average of 11,761 pairs breeding throughout the 1990’s. This is over 1% of the global population. Black Tern, Common Tern, Herring Gull, and Great Black-backed Gull also nest on the islands.
This site is a good breeding area for dabbling ducks. In particular, Gadwall nest on the islands in high densities. This site is also an important spring staging area for Bufflehead and Common Goldeneye. More than 2% of the total St. Lawrence River population of these two species may stage on the Contrecoeur archipelago.
The site has a diversity of marsh-breeding birds, including: American Bittern, Common Moorhen, Black Tern, Pied-billed Grebe, Virginia Rail, Marsh Wren and Swamp Sparrow. In addition, Savannah Sparrow, Song Sparrow, and Willow Flycatcher are common in tall grass and shrubby areas. Almost a third of the province’s breeding population of Wilson’s Phalarope occur in the archipelago, and there are also small populations of Nelson’s Sharp-tailed Sparrow and Sedge Wren. Great Blue Herons also raise young here. In late summer, emergent grasses on the north shore of St. Ours Island are a roost for thousands of swallows. Between one and three Caspian Terns have been seen in the breeding season, but breeding has not been confirmed.
BirdLife International (2019) Important Bird Areas factsheet: Réserve nationale de faune des Îles-de-Contrecoeur. Downloaded from http://www.birdlife.org on 19/03/2019.