 They migrate across the Dolphin and Union Strait from their summer grazing on Victoria Island to their winter grazing area on the Nunavut-NWT mainland in Canada.It is unusual for North American caribou to seasonally cross sea ice and the only other caribou to do so are the Peary caribou who are smaller in size and population.In the Canada 2016 Census the population of the island was 2,162; 1,766 in Nunavut and 396 in the Northwest Territories.