Fly Away Home (film, 1996)
https://en.wikipedia.org/wiki/Fly_Away_Home

Inspired by true events, Fly Away Home dramatizes the actual experiences of Bill Lishman who, in 1986, started training Canada geese to follow his ultralight aircraft, and succeeded in leading their migration in 1993 through his program "Operation Migration". The film is also based on the experience of Dr. William J. L. Sladen, a British-born zoologist and adventurer, who aided Lishman with the migration.