In 1970 Mangelsen moved to Nederland, Colorado. He spent two years living in the Rocky Mountains in an old mining shack without electricity or running water with his English setter, black lab and raccoon. Tom continued to work on his photography and studied arctic alpine ecology at the University of Colorado’s Mountain Research Station near Nederland. There he met Bert Kempers, a CU film producer, who later hired Tom as cinematographer and film editor for his company Westwind Productions, making educational and nature documentaries. Tom longed to make a documentary about the Platte River and its great wildlife resource. He returned to the Platte each spring to film the great crane migration. These experiences led to Tom traveling to the cranes’ nesting grounds in Alaska and their wintering areas in Texas. National Geographic television wanted to produce a documentary, which would chronicle the plight of the endangered whooping crane and the efforts to bring them back from the brink of extinction. After learning that Tom had been photographing sandhill and whooping cranes for more than ten years, they hired him as cinematographer and associate producer for the television special Flight of the Whooping Crane, which was nominated for an Emmy award. Mangelsen also photographed and produced the PBS NATURE and BBC Natural World film, Cranes of the Grey Wind, a documentary on the life cycle of the sandhill crane.
Initially Mangelsen was fascinated with photographing birds in flight. In the early 1970s, Tom and his brother David began selling limited edition prints of his images. In 1978, Mangelsen opened his first Images of Nature® gallery in Jackson, Wyoming. Since then a number of Mangelsen®—Images of Nature Gallery locations have opened across the United States.
Source: https://www.mangelsen.com/biography
