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Location Canada, Ontario
Central coordinates 94o 40.96' West  49o 2.24' North
IBA criteria A4i
Area 10 ha
Altitude 318 - 323m
Year of IBA assessment 2008

Bird Studies Canada/Nature Canada

Site description The Three Sisters Islands are located in the southern part of Lake of the Woods in northwestern Ontario. The town of Rainy River is about 35 km to the south. Two of the three rocky islands are vegetated with only sparse grasses, nettles and smartweed. The third island contains an area of shrubs and trees near its centre. There is little soil on the islands, and the climate is relatively dry, and prairie-like. The islands are situated well out in the lake, about 3 km from the nearest large land mass (Bigsby Island).

Key Biodiversity The Three Sisters Island group supports the largest colony of American White Pelicans in Ontario, and is one of the largest pelican colonies in Canada. In 1993, a population of 7,500 breeding pairs was estimated. This may represent as much as 8.8% of the worlds estimated population. Pelicans first began nesting on these islands in 1965 with the population increasing dramatically since that time. Numbers at the site escalated from 235 birds in 1968, to 1,684 pairs in 1981, to over 6,500 pairs in 1986. Herring Gulls and Double-crested Cormorants, which are often found in close association with pelicans, also nest on these islands.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
American White Pelican Pelecanus erythrorhynchos breeding  1995  7,500 breeding pairs  A4i  Least Concern 


IUCN habitat Habitat detail Extent (% of site)
Shrubland Scrub  -

Land use

Land-use Extent (% of site)
not utilised -

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Three Sisters Islands. Downloaded from on 28/10/2016

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