Elsie Cassels (February 1864 - 12 November 1938) was a Scottish born naturalist, the first woman to become Vice-President of a Canadian naturalist society. Cassels lived in Red Deer, Alberta and became a recognised authority across Canada on migratory birds who exchanged information (from detailed observations from 1920 to 1935), with the leading (male) ornithologists of her day, 'her keen enthusiasm stimulated a wide interest in ornithology'. Cassels objected to game hunting for pleasure as a conservationist before this was a common approach to wildlife, and helped found a bird sanctuary and in 1924 one of the first Canadian wildlife refuges at Gaetz Lakes, Alberta.