Summer on the Hudson Plain sees the greatest numbers and variety of wildlife. It is associated with the nesting and rearing stages of millions of Snow Geese, which migrate to Canadian wetlands from areas as far south as the Gulf of Mexico. Other migratory bird species returning to these lowlands include Canada Goose, Black Duck, Oldsquaw, King Eider, Pintail and Whistling Swan. While fewer in number, upland bird species such as Willow Ptarmigan, Spruce Grouse, Snow Owl, and Raven can also be found and are among the few year-round residents. Osprey, Gyrfalcon, Duck Hawk and Peregrine Falcon are birds of prey reported in the area. Small mammals include Muskrat, Ermine, Weasel, Marten and Wolverine. Large mammals have traditionally been more abundant in the interior Shield country to the south, but Woodland Caribou, Moose, Black Bear and Timber Wolves are not unknown. Other species include the Canada Lynx, Snowshoe Hare, and Striped Skunk.
Closer to the coast are such species as Polar Bear, which ventures onto the sea ice in winter, and Arctic Fox. Marine mammals include Walrus, Bearded, Ringed and Harbour seals, along with Beluga Whale and the rare Bowhead whales.
Famous in many arctic areas are the clouds of insects. In summer the abundant and poorly drained wetlands provide the ideal breeding ground for massive numbers of mosquitoes and other biting insects. An area of one hectare can produce more than
The common fish found in inland streams and lakes are Brook Trout, Northern Pike and Walleye. Some, including the Brook Trout, are migratory, wintering in the interior lakes and summering in the river mouths and estuaries of Hudson Bay.