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Site description (2001 baseline)
The Lancaster Sound Polynya is located between the northwestern end of Baffin Island and the south coast of Devon Island. The shape and extensiveness of the polynya (an area of open water surrounded by ice, varies from year to year) and associated leads is influenced by the severity of the winter, water currents and winds. Landfast ice starts to develop in late September, with the sound becoming completely ice-covered by mid to late October. Leads and cracks begin to form between mid November and mid December, and remain until break-up. One of the most regularly occurring leads is one that develops along the south coast of Devon Island. In the 1970s break-up occurred any time between early May and August. Many large marine mammals, such as Bearded Seals, Belugas, Walruses and Polar Bears, feed in the waters here.

Key biodiversity
The Lancaster Sound Polynya supports an amazing number of migrant Dovekies. During the latter half of May, this small alcid is migrating north to its breeding grounds in the Thule District of northwest Greenland, where many millions of Dovekies breed. On route, they stop at the Lancaster Sound Polynya to feed along the ice edges and loose drift ice of the open water found here.

In the latter half of May, 1976, aerial surveys of the eastern end of Lancaster Sound led to estimates of 1.5 million Dovekies. During the same time of the year in 1978, aerial surveys of an adjacent area in the sound led to estimates of 6 million and 14 million Dovekies. This is a significant portion of the Thule breeding population and an outstanding number by any measure.

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Recommended citation
BirdLife International (2025) Important Bird Area factsheet: Lancaster Sound Polynya (Canada). Downloaded from https://datazone.birdlife.org/site/factsheet/lancaster-sound-polynya-iba-canada on 08/01/2025.