The Canal de Beauharnois is a branch of the St Lawrence River that flows on the south side of the Ile-de-Salaberry just west of Montreal. The site stretches from the upper side of the Beauharnois Dam, to the western mouth of the canal were it meets Lac St-François. Hungry Bay, immediately to the south of this mouth is also included. There are a diversity of wetland habitats here including: open water, marsh, wet shrubby areas and sandy shorelines, although cattails and Phragmites are the most common shoreline plants.
Waterfowl are abundant in the Canal de Beauharnois during migration. Snow Geese are the most common species with recorded high counts of 20,000 in the fall at the St-Louis-de-Gonzague pond, and 50,000 in the spring at Hungry Bay. Many thousands of Canada Geese use the area in both the spring and fall. Seven thousand have on different occasions been counted in the Hungry Bay and canal sections of the IBA in spring. A wide variety of ducks and have been recorded here, a few of which also breed on site. Up to 2,000 American Black Ducks (or about 1% of the Atlantic flyway population) have been seen in the spring. Other common migrants (followed by recorded highs) are: Mallard (9,980), American Widgeon (1,200 in St-Louis-de-Gonzague section), Ring-necked Duck (1,000 in St-Louis-de-Gonzague section), scaup, Common Goldeneye, and Common Merganser.
There are two colonies of Common Terns on artificial islands associated with the Laroque and Saint-Louis bridges. In total, roughly 250 pairs of terns nest here. Two other species of interest breeding in the canal are Black Terns (42 were recorded in the St-Louis-de-Gonzague marshes in 1993) and Least Bittern (probably breeding in three locations within the canal). Up to five Great Egrets have also been seen here in the post-breeding season. One study conducted during the summer months recorded 111 species in the canal – the most numerically abundant species were Mallard, Ring-billed Gull (see the Barrage de Beauharnois IBA) and Tree Swallow.
Large numbers of blackbirds and Starlings used to be seen here; these birds roosted here in the beds of Phragmites. Red-winged Blackbirds and Starlings dominated the flocks, but Common Grackles and Brown-headed Cowbirds were also common. In recent years, Phragmites control measures have been taken, which has noticeably reduced the numbers of blackbirds. Now, only a few thousand blackbirds are seen.
BirdLife International (2020) Important Bird Areas factsheet: Canal de Beauharnois. Downloaded from http://www.birdlife.org on 23/11/2020.