Churchill & Vicinity (MB003)
Altitude 0 - 30m
Superficie 1 513,74km²
Description du site
This well-known site covers a large area around the town of Churchill, Manitoba, a port on Hudsons Bay. Most of this area is exceedingly flat; the only variation in elevation comes from the Precambrian rocky ridge that follows the shoreline. The number of habitats found here is particularly high: in the southern portion, black spruce forests dominate, and in the north a band of wet and dry tundra parallels the coast. Within both regions are found ponds, lakes marshes and muskeg. Tidal flats and marshes are another important habitat for birds. The Churchill River, on the western side of the site, runs northward into Hudson Bay to where the town is situated. The best known mammal of the region is the Polar Bear, since Churchill is the largest denning area in the world. Seals, Caribou, Timber Wolves and Beluga Whales are also here in the summer; the latter congregate in the Churchill River estuary in the thousands to feed and give birth.
The Churchill area is known across North America for breeding and migratory birds that can be seen between June and September. Churchill has 95 breeding bird species, with over 250 species recorded in total. Many of these species are tundra breeding shorebirds, or pond and marsh breeding waterfowl. The most numerous, and the most famous of these, is the Snow Goose. In 1997, about 66,000 mid-continent Snow Geese bred in the salt marshes of La Perouse Bay, east of the town (2% of all mid-continent Snow Geese); it was estimated that 30% more birds were present if non-breeding adults were included. Churchill also has large numbers of migrating waterbirds. The Black Scoter and Harlequin Duck are two ducks that pass through in significant numbers. In the spring, over 4% of the eastern population of Black Scoters passes through, while about 1% of the endangered eastern Harlequin Duck population is seen (assuming all eastern birds). Of the many shorebirds seen at Churchill, the Ruddy Turnstone is the most significant since up to 2.5% of the North American population can be seen in spring migration; a maximum of 6,000 birds were recorded in June, 1982. Over 3,500 Red Knots were recorded in the spring of 1974, which represents about 3% of the C.c. rufa subspecies. In July, 1999, over 1,500 Whimbrel were observed at Cape Merry, which represents at least 2.6% of the North American population.
Perhaps the bird that most symbolizes Churchill to birders is the Ross Gull (nationally vulnerable). This primarily Eurasian bird breeds in only two locations in Canada. Since 1978, an average of one pair has nested at this site, although in some years numbers have been as high as 6 pairs. A few of the many land-based birds at Churchill are: the Peregrine Falcon (up to 10 migrant birds); Willow Ptarmigan (breeding, and over 700 migrating birds); and Snow Bunting (fall, 12,000+).
Enjeux de conservation
In 1996, the Churchill IBA and a much larger surrounding area were designated as Wapusk National Park. The park management board holds members from several local interests, and all three governmental levels. In addition to park protection, the Ross Gull nesting location, Akudlik Marsh, is protected as a special conservation area.
The Lesser Snow Geese population has exploded over the last few decades; this has meant increased salinity levels and vegetation change. Now, over half of the intertidal salt marshes in the region are no longer productive. Numerous biologists are extremely concerned and have recommended a reduction in their population, primarily through increased hunting. Other conservation concerns at Churchill include, environmental stress from tourism, gravel extraction and weir construction on the river. The first two are of concern partly because almost any heavy use of the arctic tundra can cause scarring and permafrost melt.
Menaces Potencielles ou Existantes
Status de Protection