Île aux Hérons Migratory Bird Sanctuary

The Îles aux Hérons Migratory Bird Sanctuary (MBS) is located between Montreal Island and the south shore of the St. Lawrence River, in Québec. The great blue heron uses this habitat to nest.

Importance of the sanctuary: migratory birds and other wildlife

Located south of the Island of Montreal, the Île aux Hérons Migratory Bird Sanctuary covers 631 hectares and encompasses most of the Lachine Rapids. This sanctuary was established in 1937 in order to protect an essential nesting site for the great blue heron.

Great Blue Heron
Great blue heron. Photo:  Simon Pierre Barrette

The size of the heron’s colonies varies from one year to another. Despite the protection that the sanctuary provides to the population of great blue herons, their number has fluctuated substantially within the sanctuary in the past years. The number of nesting heron has been bigger in the 1990s compared to the 1970 to 1980 decade. Since the 2000s the number of occupied nests has been decreasing. The numbers of nesting black-crowned night herons has been on the rise. The great egret also nests in this sanctuary but in lesser numbers.

Great Blue Herons

Great blue heron. Photo: Benoît Audet

Did you know?

When hunting, the great blue heron stands absolutely still in the water and waits for something mouthwatering to swim by; then the bird strikes and, if it was successful, it tries to swallow its meal whole.

Despite the name of this migratory bird sanctuary, many different species of birds use Île aux Hérons for feeding, resting or nesting. Birds known to nest in the sanctuary include:

During migration, waterfowl, such as common goldeneye, American black duck, mallard and green-winged teal are also regularly observed at the site. Horned grebes can be spotted here on occasion as well and, during the winter months, a number of red-breasted mergansers make use of this site.


Île aux Hérons Migratory Bird Sanctuary not only encompasses the island named Île aux Hérons, but also a number of islands and islets in the area including Île au Chèvres and Île au Diable as well as Île à Boquet, which runs along the St. Lawrence Seaway. The sanctuary also includes the waters surrounding these islands.

The vegetation found on these low-lying islands is composed of trees such as American basswood, American elm and slippery elm as well as herbaceous plants and shrubs like giant St. John’s wort and staghorn sumac. Some of the islands also support a few endangered plant species such as butternut and green dragon. The waters around these land masses support plants such as:

Map of the area

Map of Île aux Hérons MBS

Access to the sanctuary

Migratory Bird Sanctuaries, such as Île aux Hérons, are established across the country to protect migratory birds during critical periods of their migration. Whether these areas are used for feeding, resting or nesting, they play an important role in the survival of many species. Please ensure that you are aware of how, as a visitor, you can help protect this sanctuary and, before accessing the site, please read the restrictions, including those on firearms and hunting, that are in place to conserve the wildlife that call it home. It is also important to remember that pets are not welcome inside Migratory Bird Sanctuaries.

If you would like further information on what is permitted in Migratory Bird Sanctuaries, please visit the Management and Activities section of the website. For more information on Île aux Hérons Migratory Bird Sanctuary in particular, please contact our regional office.

Key facts about Île aux Hérons Migratory Bird Sanctuary

Protected Area designation Migratory Bird Sanctuary
Province or territory Québec
Latitude/longitude 45° 25' 00" N 73° 35' 00" W
Size 631 hectares
Date created (Gazetted) 1937
International Union for Conservation of Nature (IUCN) management category Natural Monument or Feature (III)
Additional designations Île aux Hérons Migratory Bird Sanctuary Important Bird Area
Nature Reserve on private lands (in part)
Main habitat type Submerged beds and woodland
Key bird species Great blue heron
Other species Birds: Black-crowned night heron, great egret, America black duck, American wigeon, mallard, gadwall, red-winged blackbird, yellow warbler, common goldeneye, green-winged teal
Plants: American elm, Eurasian watermilfoil, alisma plantago-aquatica, sago pondweed, Americana tapegrass, water stargrass, tuberous waterlily, white snakeroot, small skullcap, giant St. John's wort, staghorn sumac
Listed species under the Species at Risk Act (SARA) Partial list:
Butternut, green dragon
Management agency Canadian Wildlife Service, Quebec Region

Related links

Île aux Hérons Migratory Bird Sanctuary on Google Maps (Please note that the Google map is a complementary source of information and does not represent the official map or site name)

Contact information

Environment and Climate Change Canada – Quebec Region
Canadian Wildlife Service
Protected Areas Unit
801-1550, avenue d'Estimauville
Québec, Quebec G1J 0C3

Toll-free: 1-800-668-6767 (in Canada only)
Email:  enviroinfo@ec.gc.ca

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