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Anderson River Delta (NT038)


Anderson River Delta (NT038)

Anderson River, Northwest Territories

Latitude 69.750°N
Longitude 128.581°W
Altitude 0 - 25m
Area 759.20km²

Site Description

The Anderson River IBA follows the lower 50 km of the Anderson River and includes most of Wood Bay, on the north coast of Northwest Territories. A nearby, but unconnected, piece of land - the lower 20 km of the Mason River is also included. The land is low-lying, but not completely flat, and sits on Cretaceous sedimentary rock. Lakes and ponds are common in the surrounding area and the river breaks up into several channels at the delta.

At the highest reaches of the site the surrounding land is spruce forest, Dryas tundra is found a little farther down, and at the river delta the vegetation is made up of grasses, sedges and willows. Part of the river delta was a glacial refugia in the last ice age and thus some plants and insects found here show an unusual distribution.

An Inuit community was once supported by the abundant wildlife; remains of this community can still be found in places. Barren-ground Grizzly are common and both Caribou and Moose are seen at this tree-line site.


Many species of waterfowl use the Anderson River for breeding, moulting and staging. The western subspecies of Brant (nigricans or Black Brant) breed in the outer delta. About 2% of the Black Brant population, or 2,500 birds, are here from late May through to August or September. An additional 100 Brant breed on the Mason River. A second species of waterfowl, the Tundra Swan, breeds here in small numbers, but significantly more (1,200 or over 1% of the eastern population) stay to feed and moult in summer.

Other goose species are common in the area. In 1995, at least 3,600 Lesser Snow Geese of the Western Central Flyway population bred on the islands at the mouth of the Anderson River. Several hundred of these Geese bring their broods over from the Anderson River to the Mason River. Both the Anderson and Mason river deltas support about 1,000 moulting Greater White-fronted Geese.

Numerous other birds breed, moult, and stage in the area. Large numbers of Oldsquaw, scaup, scoters, dabbling ducks (3,000 5,000), shorebirds, raptors and songbirds are all found in the delta. The Mason River also supports 50 pairs of Glaucous Gulls.

The Eskimo Curlew used to breed here. This shorebird is globally listed as critical and nationally listed as endangered, but may now be extinct. The bird was last seen somewhere along the Anderson River in 1989.

Conservation Issues

Although some seismic work took place in the 1970s, there has been no exploration or similar activities in the Anderson River area since that time. The river is popular for canoe trips. Disturbance from canoeists or other visitors is one of the few ways that breeding or moulting waterfowl could be disturbed.

Apart from the Mason River section, this site lies within the Anderson River Delta Migratory Bird Sanctuary. This status gives the birds full protection, whereas the other designations, namely the International Biological Programme and Key Migratory Bird Habitat Site of the Northwest Territories do not.

IBA Criteria Habitats Land Uses Potential or Ongoing Threats Conservation Status
Eskimo Curlew
Number Year Season