Dr. William J.L. Sladen, a former professor at what is now Johns Hopkins University’s Bloomberg School of Public Health who became an internationally known authority on birds and whose exploits were dramatized in the 1996 Hollywood film “Fly Away Home,” died May 29 of respiratory failure at his home in Warrenton, Va. He was 96.

Dr. Sladen, who retired in 1990 from Hopkins, where he taught comparative behavior and ecology, first went to Antarctica in the 1940s as a British medical officer and returned many times for his zoological research, practically commuting to and from the continent in the 1960s.

His research helped reveal the intrigue of Antarctic wildlife, including the Adelie penguin, which is smaller than the better-known Emperor penguin. In a 1966 article published in the journal Nature, he reported that he had detected trace amounts of DDT in Adelie penguins and a crabeater seal, helping to reveal the extent of the environmental threats that the pesticide posed. DDT was banned in the United States in 1972.

Two mountains in Antarctica were named for Dr. Sladen, whose research also extended to the North Pole region. He was credited with using radio technology to document the trek of the tundra swan, which covered thousands of miles, from the Arctic to the Mid-Atlantic.

He was perhaps most popularly known for his effort, undertaken with Canadian artist and pilot William Lishman, to teach Canada geese a migratory route from Ontario to the Airlie conference center in Warrenton using an ultra-light aircraft as their guide.

The project, called Operation Migration, began in 1993 and was featured on television shows including the news magazine “20/20.” The film “Fly Away Home,” for which Sladen served as a technical adviser, starred Jeff Daniels and Anna Paquin as a father-daughter duo that takes on a similar project.

The experiment, in which the aircraft took the lead spot in the geese’s traditional V formation, was successful. George Archibald, a founder of the International Crane Foundation, credited Dr. Sladen’s ideas with influencing the reintroduction to eastern North America of endangered species including the whooping crane and the trumpeter swan.

Dr. Sladen earned two medical degrees in London, including one with a specialty in bacteriology, before completing a doctorate in zoology at the University of Oxford in 1955. Soon after, he settled in the United States, becoming a U.S. citizen in 1962.

—The Washington Post