The Rasmussen Lowlands are located in the central Canadian Arctic near the base of the Boothia Peninsula. They extend along the eastern side of Rae Strait and the Rasmussen Basin, from the south shore of Netsilik Lake to approximately 45 km north of Arrowsmith Bay. Much of the area is poorly drained, flat lowlands covered with marine silts and sand. The terrain is increasingly rugged in the eastern and northern portions of the Lowlands with the Ross Hills and Wager Highlands bordering the north and east sides respectively. Habitats in the Lowlands vary from partially vegetated, dry tundra with beach ridges and eskers, to richly-vegetated sedge wetlands. Numerous tundra ponds are found throughout the area.
Intensive wildlife surveys completed in the Lowlands during 1976 documented high numbers of several waterfowl and shorebird species. Additional surveys in 1994 and 1995 confirmed the sites significance, though population estimates were lower for several of the species. At least four species were recorded in significant numbers during the 94/95 season: Tundra Swan (almost 2% of the North American population), Greater White-fronted Goose (as much as 3% of the mid-continent population), Snow Goose (3.8% of the Alaska/NW Canada population), and King Eider (as much as 12% of the estimated western Atlantic breeding population). Large numbers of Pacific Loons were also recorded. A later estimate in 1998, revealed 28,000 Snow Geese solely in the Inglis River region of the Rasmussen Lowlands.
Large numbers of nesting shorebirds have also been documented in the Rasmussen Lowlands. During the 1976 study it was estimated that the Lowlands supported about 500,000 shorebirds - mostly Red Phalaropes (40%) along with White-rumped Sandpipers, Pectoral Sandpipers, American Golden-Plovers, Black-bellied Plovers and Semipalmated Sandpipers. Surveys undertaken in 1994 and 1995, however, documented much lower numbers of Red Phalaropes, Black-bellied Plovers, and American Golden Plovers. Estimates for other shorebird species were not significantly different from those generated in the 1970s. The number of shorebird species nesting on the Lowlands is higher than at most other Arctic sites where shorebird studies have been completed.
The Rasmussen Lowlands are also significant in the context of biome-restricted species assemblages. In total, 36 species have been confirmed as breeders. Of this number almost two-thirds have breeding ranges largely restricted to the Tundra biome. In all, the Rasmussen Lowlands support breeding populations of 21 out of the 33 species that have been identified as largely restricted to the entire Tundra biome. Within the Lowlands, some of the more abundant biome-restricted species include: Greater White-fronted Goose, Pectoral Sandpiper, Red Phalarope, Semipalmated Sandpiper, White-rumped Sandpiper, and Lapland Longspur.
The escarpment bordering the Lowlands supports a large population of nesting Peregrine Falcons (ssp. tundrius - nationally vulnerable). In 1995, 80 pairs were recorded (possibly as much as 6% of the national population).
BirdLife International (2020) Important Bird Areas factsheet: Rasmussen Lowlands. Downloaded from http://www.birdlife.org on 25/10/2020.