Île Deslauriers is part of the Varennes Archipelago in the St. Lawrence River, just east of Montréal and directly north of the town of Varennes. The western part of the island contains mounds of sediment from dredging of the river. In spring, about 30% of the island becomes submerged.
Vegetation on the island consists of short grasses, and Black Mustard and dandelions grow on the spoil piles. Aquatic vegetation is composed of arrowhead, Sago Pondweed and Spiked Water-milfoil.
An extremely large Ring-billed Gull colony is located on Île Deslauriers. Over the past two decades, the colony has substantially increased in size. At last count in 2000, 51,667 pairs (5% of the global Ring-billed Gull population) nested on the island, which makes this colony the largest in Québec as well as one of the largest in Canada, and represents over 5% of the world’s population.
A population of Black-crowned Night-Herons has recently become established on the island and has shown a large increase in recent years. In 1994, 28 pairs nested on the island, and in 1997 there were 49 pairs. Compared to other nearby islands, Île Deslauriers hosts large numbers of breeding Gadwall and other waterfowl species. A Bank Swallow colony is also located on the northeast part of the island.
BirdLife International (2019) Important Bird Areas factsheet: Île Deslauriers. Downloaded from http://www.birdlife.org on 27/06/2019.