Sites - Important Bird Areas (IBAs)

Ornithological information 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.

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).

Populations of IBA trigger species

Habitats

Land use

Conservation response Fish-eating birds such as pelicans and cormorants are often perceived as a threat to commercial fishing interests. As a result nests and adults are often destroyed. At their breeding colonies, American White Pelicans are very sensitive to disturbance and will abandon their nests, leaving their eggs and/or young exposed to predators and inclement weather. Most research has confirmed that pelicans prey mainly on minnows, and non-game species of larger fish that are of little importance to the fishing industry.

The breeding colony on the Three Sisters Islands is afforded some natural protection by the large expanse of water surrounding the islands, which are remotely located and difficult to access due to the rocky shorelines. The Three Sisters Islands group is one of the few sites in Ontario where American White Pelicans regularly nest.

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Recommended citation  BirdLife International (2013) Important Bird Areas factsheet: Three Sisters Islands. Downloaded from http://www.birdlife.org on 26/05/2013

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