The Middle Arctic tundra ecoregion (WWF ID: NA1115) covers a broad stretch of northern Canada - the southern islands of the Arctic Archipelago, plus the northern mainland of Nunavut and, across Hudson Bay to the east, a portion of northern Quebec. This is the coldest and driest ecoregion in Canada, and can be referred to as a 'polar desert'. It is an important region for breeding and migratory birds, and supports 80% of the world's muskox.