The Moose River estuary is located along the southwestern coast of James Bay, about 20 km northeast of Moosonee. The site stretches north and east from the mouth of the Moose River, for about 10 km in each direction and it includes Ship Sands Island, which is located on the northern side of the rivers mouth. Moose River is one of the two largest rivers flowing into James Bay and shoals and mudflats extend 8 to 10 km offshore as a result of deposition. The tidal flats are over 1 km wide to north of Ship Sands Island. These flats are covered by a mosaic of sedges and other plants, amidst shallow pools and drainage ways. The seaward third of Ship Sands Island is covered with sedge marshes that are seasonally flooded. A succession of low gravel ridges, with supertidal marshes between, extends over a km inland from the normal high tide.
Tremendous numbers of staging Snow Geese have been recorded in the Moose River estuary during fall migration. In 1980, approximately 179,000 geese were counted at this site. Although numbers of Snow Geese using this area have declined somewhat, there is no doubt that numbers present are still of global significance.
In addition to geese, large numbers of other waterbirds utilize this site. Examples of one-day counts include: American Black Duck (200), Green-winged Teal (180), Lesser Scaup (200), Common Snipe (200), and Black-bellied Plover (40 to 50), Dunlin (1,000), and Sandhill Crane (42). As a whole, however, few detailed surveys of this area have been completed. For example, the flooded foreshores to the east of Moose River is an area of very heavy use by returning dabbling ducks during the spring, but no population estimates are available.
At least 45 species have shown some evidence of breeding on Ship Sands Island. These species include Northern Harrier, Le Contes Sparrow, Nelsons Sharp-tailed Sparrow, Marbled Godwit, and Yellow Rail. Yellow Rail was recently identified as a nationally vulnerable species: it is recorded as being common at this site.
Conservation responses/actions for key biodiversity
The extensive mudflats and coastal marshes of the estuary provide rich food sources for migrating birds. As a whole, the southern James Bay region, where this site lies, is one of the most important northern stopover areas for migrating Arctic-breeding waterfowl and shorebirds. Some equate it only with the Copper River Delta and Bristol Bay in Alaska, and with the upper Bay of Fundy in New Brunswick.
In recognition of this significance, the Moose River Migratory Bird Sanctuary was established to help protect the habitat. In 1987, this site was also identified as a Wetland of International Importance under the Ramsar Convention.