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Location Canada, Ontario
Central coordinates 85o 6.00' West  55o 16.87' North
IBA criteria A4iii
Area 150,000 ha
Altitude 0 - 10m
Year of IBA assessment 2008

Bird Studies Canada/Nature Canada

Site description The Winisk River enters Hudson Bay near the midpoint of the northern Ontario Hudson Bay coastline. The site includes the Winisk River estuary and the shores and associated marshes extending about 15 km east and 20 km west of the river. The river mouth contains a number of islands and interconnected river channels, while the shores along the coast have wide intertidal marshes and submerged shoals that extend for 1 km or more offshore. Supertidal marshes extend as far as 10 km inland among drier low raised beach ridges with heath lichen. This habitat extends for about 10 to 15 km in each direction of the river mouth. Farther from the river, raised beach ridge systems become more prominent, with numerous small lakes and ponds being located between tundra covered strips.

Key Biodiversity Large congregations of geese occur along the Winisk River coastline during both the spring and fall migration. A one-day count of 8,200 Canada Geese was recorded in the late1970s, representing from 1% to 2% of the estimated Mississippi Valley wintering population. Large numbers of Lesser Snow Geese (ssp. caerulescens) have also been recorded at this site during both the spring and fall migrations. In the late 1970s, about 75,000 birds were recorded during the spring migration, and during the fall, a one-day total of 56,500 geese was recorded. Both of these totals represent well over 1% of the estimated Hudson Bay population.Other birds found at this site include up to 100 staging Tundra Swans, nesting Arctic Terns and Yellow Rails (nationally vulnerable) and thousands of nesting and moulting ducks.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
A4iii Species group - waterbirds passage  1994  50,000-99,999 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)
Shrubland Scrub  -
Grassland Tundra  -
Wetlands (inland) Estuarine waters; 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: Winisk River Estuary. Downloaded from on 22/10/2016

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