However, the current migration route is undergoing continuous industrial development such as power lines, microwave towers, and urbanization, which all pose major threats. Southward migration from Wood Buffalo begins in mid-September. Whooper parents with new chicks are usually the last to head south for the winter. The short summer season allows just enough time for the chicks to fledge before the cold weather arrives. The 2,500-mile migration route through Alberta, Saskatchewan, Montana, the Dakotas, Nebraska, Kansas, Oklahoma, and Texas takes approximately four to six weeks to complete.
Migration is a dangerous time for Whooping cranes and other migratory birds.
Collisions with power lines represent a leading cause of death, especially for inexperienced young birds. In 1946, Robert Porter Allen was appointed by the National Audubon Society to study the life history of Whooping cranes on the Texas wintering grounds, trace their migration route, and search for their nesting area. Allen searched thousands of square miles of Canadian wilderness before the breeding grounds were accidentally discovered in 1954. Returning from a forest fire near the Hay River, a fire crew sighted three Whooping cranes from a helicopter. One year later, Allen and Robert Stewart confirmed the nesting area when they actually located a Whooper nest.