Thelon River

Country/territory: Canada

IBA criteria met: -
For more information about IBA criteria, please click here

Area: 460,000 ha

Birds Canada / Nature Canada

Site description (baseline)
The Thelon River IBA covers a long stretch of the Thelon River between Eyeberry Lake and the western end of Aberdeen Lake. This site is divided between Nunavut and the Northwest Territories. The area is isolated, since the closest community is Baker Lake, 150 km to the east. It is a low and rolling area that is covered in sand pebble glacial tills. At the south end of Beverly Lake, where the Dubawnt River joins the Thelon, a large delta is present. The site is in a transitional zone, where the north end of the boreal forest meets the low arctic region. In a small middle section of the river, the riverbanks are forested with spruce, larch and willow trees. In other spots, the riverbanks are composed of low cliffs, sedge meadows, or moss-sedge vegetation complexes.

Part of the Beverly Caribou herd calve in this area and several river crossings of the herd are located here.

Key biodiversity
In late summer, from mid-June to mid-August, thousands of Canada Geese are found in this part of the Thelon River. Up to 18,000 Canada Geese have been recorded here between the 1960s and 1980s. It is unclear whether these geese are partly or wholly from the maxima, moffitti, or interior subspecies. It is probable that at least 1% of one or more of these subspecies (or a population within the subspecies) are found here.

Small numbers of two other goose species breed in the area. Between Beverly and Aberdeen lakes, 30 broods of Greater White-fronted Goose were recorded in 1960, and 140 pairs of Lesser Snow Geese bred on the islands of Beverly Lake in 1989. Raptors nest near the north shores of Beverly and Aberdeen Lakes.

Recommended citation
BirdLife International (2023) Important Bird Area factsheet: Thelon River. Downloaded from on 31/05/2023.