Île aux Hérons
Wildlife Habitat

(Cadastral map of site also available: 73 K)

Île aux Hérons, located in the middle of the Lachine Rapids, features relatively undisturbed mature forest vegetation dominated by hackberry (Celtis occidentalis), which is considered a rare forest community. Hackberry is listed among the species likely to be designated as threatened or vulnerable. The hackberry stands are truly remarkable: they occupy nearly two thirds of the island and constitute the largest population of this species in Quebec. This forest community has been successfully preserved despite the presence of cottages along the southeastern shore of the island. Associated plant species include basswood, slippery elm and American bladdernut (Staphylea trifolia), another species that is likely to be designated as threatened or vulnerable. Other rare plants can also be found on the island.

Great Blue Heron nests. Photo: Pierre Bilodeau, MEF

Île aux Hérons, as its name suggests, contains a large mixed heron colony whose population appears to have stabilized over the past few years. During a 1997 survey, 375 Great Blue Heron nests and 474 Black-crowned Night-Heron nests were counted. This is the second largest Great Blue Heron colony in Quebec, after the one on Grande-Île in the Berthier-Sorel archipelago. The Black-crowned Night-Heron population makes this one of the largest colonies for the species in North America. The île aux Hérons site also includes two rocky islands downstream from the former LaSalle power plant, featuring two Common Tern colonies. A total of 58 nests were counted there in 1985, and the present size of the tern population appears to be about the same.

Since the land is owned by Hydro-Québec, an agreement has been signed between this agency and the Quebec Department of the Environment and Wildlife with the aim of preserving the colonies. Designated as "wildlife habitat," the island and islets remain in the hands of this company, which has agreed to comply with the applicable wildlife habitat regulations. The people who live on île aux Hérons have been permitted to stay there, but their activities are governed by the regulations.

The protected site encompasses the entire heron colony on île aux Hérons, along with a 200-metre-wide protection band around the colony, and two rocky islets used as nesting habitat by Terns, for a total surface area of 31.80 hectares.

Much of this area was granted migratory bird sanctuary status by the federal government in 1937 for the primary purpose of prohibiting hunting and all activities that might be harmful to migratory birds, their eggs and nests. Since the habitat itself is not covered by the federal legislation, its recent designation as wildlife habitat has provided a means of prohibiting all activities that might alter the biotic, abiotic or physical components of this outstanding site.