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Location Canada, Ontario
Central coordinates 83o 40.20' West  55o 16.27' North
IBA criteria A4iii
Area 98,000 ha
Altitude 0 - 10m
Year of IBA assessment 2008

Bird Studies Canada/Nature Canada

Site description The Sutton River enters Hudson Bay in northeastern Ontario, about 90 km west of Cape Henrietta Maria. The IBA includes the bay at the mouth of the Sutton and Kinushseo Rivers, Little Cape, and the coastline eastward for about 40 km. Little Cape is a promontory that extends about 5 km into Hudson Bay on the north and east side of the Sutton River estuary. About one third of the cape consists of dry gravel ridges up to 9 m high, which are covered with low vegetation (grass and moss); the remainder is low, flat marshland. The Sutton and Kinushseo River estuaries are shallow and shoal filled. The areas adjacent to the river mouths and to the east consist of low marshy fens and dry heath lichen tundra on low beach ridges. Marshes and fens extend inland for 10 to 15 km through open tundra. The shoreline has wide intertidal marshes and submerged shoals extending for at least 1 km offshore.

Key Biodiversity The Sutton River coastline is a significant staging, breeding and moulting area for large numbers of waterfowl. During fall migration, large numbers of Lesser Snow Geese stage at this site, with a one-day count in excess of 23,000 having been recorded. Notable numbers of Tundra Swans have also been recorded at this site during the late summer, with 500 to 600 often being recorded here. Although few shorebird surveys have been completed at this site there is a record from the early 1950s of a one-day total of 700 Pectoral Sandpipers. Such a congregation would likely have been greater than 1% of the estimated North American Pectoral Sandpiper population.

Over the last ten years, Lesser Snow Geese have started to nest in increasingly large numbers in the coastal marshes from the Kinushseo River eastward for about 30 km. It is now estimated that about 20,000 Mid-continent Snow Geese breed at this site. Common Eiders (ssp. sedentaria) has also nested in significant numbers at Little Cape. Although recent population estimates are not available, it is likely that if the colony is still present it would be significant given the small population of ssp. sedentaria. Other notable bird species that breed at this site include King Eider (one of the few breeding sites for this species in Ontario), and Dunlin.

During the summer, large flocks of moulting Black Scoter have been observed; in 1994 a one-day count of 1,250 scoters was recorded, which represents about 1% of the estimated eastern North American population. Large flocks of other ducks, such as Northern Pintail, Common Goldeneye, Oldsquaw and White-winged Scoter, have also been recorded in what appear to be moulting aggregations.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
A4iii Species group - waterbirds non-breeding  20,000-49,999 individuals  unknown  A4iii   

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Polar Bear Provincial Park 2,355,200 protected area overlaps with site 34,000  
Polar Bear Provincial Park Wetlands of International Importance (Ramsar) 2,408,700 protected area overlaps with site 31,000  


IUCN habitat Habitat detail Extent (% of site)
Grassland Tundra  -
Wetlands (inland) Estuarine waters; Fens transition mires & springs; Freshwater marshes/swamps; Intertidal mud, sand or salt flats; Salt/brackish marshes  -
Sea Open sea  -

Land use

Land-use Extent (% of site)
hunting major

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Sutton River Coastline. Downloaded from on 26/10/2016

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