Black-crowned Night Heron
A bird sanctuary

Granted in 1672 by steward Jean Talon to Zacharie Dupuis, the fief on Île aux Hérons became the property of the Congregation of Notre-Dame the following year, as Zacharie Dupuis and his wife gave the Congregation their properties, the fiefs on Île aux Hérons and in Verdun, in exchange for lifetime living accommodations. 

The religious community then sold Île aux Hérons and the adjacent islands, on July 1, 1698, to Antoine Trottier-Desaulniers-Desruisseaux. Over the centuries, ownership of the property was passed on from one owner to the next until it fell into the hands of government-owned Hydro-Québec—when electricity was taken over by the provincial government and electricity companies became publicly owned in 1962—before being more recently transferred to a non-profit organization. In the 20th century, the fief no longer existed and the islands of the Lachine Rapids became a sanctuary for migratory birds.

Almost all the summer cottages on Île aux Hérons—some forty in all—are located along the southeastern escarpment of the island, interfering very little with the aquatic vegetation consisting, for example, of spiked water-milfoil, northern water plantain, sago pondweed, tape grass, tuberous water lily and small skullcap.