This site is on the north shore of the St. Lawrence River, near the village of Baie-Ste-Catherine. It consists partly of extensive tidal flats, which are flooded by strong tides, and partly of the adjacent deeper water at the mouth of the Saguenay River (embouchure de Saguenay). Except for a small forested area, the Batture aux Alouettes is defined by the mean high and low tide levels. The Spartina alterniflora marsh is one of the rare salt marshes of the north shore. There is one small island in the site which has sparse grassy vegetation. The shoreline is steep and mostly covered with mixed woods.
The avifauna of the batture is mainly characterized by flocks of migrating shorebirds - it was identified as a potential Western Hemisphere Shorebird Reserve Network regional site. The high numbers found are very likely an underestimation since the mudflat is 5 km wide in places, making precise counts difficult. Although the highest total count is 8,632 in 1989, it is probable that this site's shorebird flocks meet the national threshold of 10,000. Three species, however, are definitely present in significant numbers. As many as 1,600 Red Knots were tallied in one day, representing over 1% of the North American population. Sanderling has the highest one-day count of any individual shorebird species, with 2,800 recorded in 1989; this accounts for over 1% of the global population. Finally, Purple Sandpiper has been recorded in winter in significant numbers: 120 birds were recorded in the winter of 1999. Other regular shorebirds include Black-bellied Plover (600 in the fall of 1989), Ruddy Turnstone, Dunlin (2,000 in the fall of 1989), Baird's Sandpiper and Pectoral Sandpiper.
There are notable numbers of waterfowl in several seasons. Diving ducks are common in the mouth of the Saquenay in winter. Barrow's Goldeneye (nationally Special Concern) is recorded in high numbers. In 1999 150, or 5% of the eastern population were recorded and earlier in 1978, 500 were counted. Oldsquaw are often seen in very high numbers, with a peak count of 25,000 in 1978, and 15,000 in 1991. Common Goldeneye are also abundant. In the fall, the area is regionally important for waterfowl, particularly dabblers. Occasionally, the nationally endangered eastern Harlequin Duck is recorded in this season. In the summer, an average of 915 Common Eider nests were recorded between 1992 and 1996. This is just over 1% of the North American S. m. dresseri population.
Other breeding birds include three colonial species: Double-crested Cormorant (4 year 1987-1999 average of 868 nests), Great Black-backed Gull (303 nest in 1999) and Herring Gull (120 nests in 1999). Since 1988, there have been nesting Bald Eagles; one of only 40 known nesting sites in the province. Up to two nests have been found in the forested part of the site. High numbers of another larid have been recorded in the fall. In 1993, 4,500 Black-legged Kittiwakes were counted.
In spring migration, Snow Buntings, Lapland Longspurs and Horned Larks can be numerous while a few Northern Harriers and Short-eared Owls (nationally Special Concern) often stop to hunt.
This site, except for the shoreline forests, is part of the Saguenay-St. Lawrence Marine Park. Three parts of the mudflat have special provincial status forbidding any habitat-modifying activity, and two more areas are Aquatic Bird Concentration Areas (Aire de Concentration d'Oiseaux Aquatiques). The island will probably be designated as a wildlife sanctuary. The site will be part of a Priority Intervention Area (Zone d'Intervention Prioritaire) and is in the World Biosphere Reserve of Charlevoix.
The landscape of the area is typified by salt marshes, intertidal rocky shore, mudflats, river's estuaries and long sandy beaches. The mixing of the cold and well-oxygenated waters with the warmer waters of the St. Lawrence favors an unusual marine biodiversity. Several marine species are commercially exploited, such as the common whelk, the soft-shell clam, the green sea urchins, the Stimpson's surf clams, the snow crab and the Atlantic herring. Moreover, the harvest of soft-shell clam at low tide is a popular recreational activity throughout the region of Lower North Shore. The north shore of the estuary is also hosting a variety of pelagic species occupying an important role in the food chain, such as the capelin and the rainbow smelt are also targeted by the sport fishermen.
The fish habitat is affected by coastal erosion, residential development, harnessing of rivers and the creation of resorts. In addition, the presence of industries discharging pollutants in the system does impacts the water quality. The Atlantic salmon is sensible to aluminum contamination through bioaccumulation of the residues present in the system.
Major species present:
Green sea urchin
Stimpson's surf clam
The landscape of the coastal region is punctuated with salt marshes. Plant species that grow are especially well adapted to survive the rigors of the environment. They occupy different parts of the marsh according to their tolerance to salinity and immersion (tides). We found there mainly cordgrass, saltmeadow cordgrass and glasswort. The tight formation of stems and the large roots network of cordgrass promote the deposition and retention of sediments, reducing coastal erosion. In areas with weak currents, eelgrass colonizes silty soils, while seaweeds attach and inhabit rocky substrates.
The destruction and loss of habitats (shoreline fill, draining wetlands, urbanization) are the main threats affecting the ecosystems of the area. Water pollution and risks of oil spills remain issues of concern. The spread of invasive species need to be monitored. It should be noted that the region is home to 18 endemic plant species, including two endangered species in Québec.
Major species present :
Cordgrass – main species
|American Black Duck|
|300 - 600||2018||Winter|
|278 - 1,975||2017||Winter|
|200 - 300||2016||Winter|
|200 - 221||2013||Winter|
|Iceland Gull (glaucoides/kumlieni)|
|35 - 100||2015||Winter|
|100 - 400||2013||Winter|
|150 - 200||2011||Winter|
|70 - 350||2005||Winter|
|150 - 700||2003||Winter|
|50 - 1,350||2002||Winter|
|150 - 175||1999||Winter|