William J. L. Sladen | Scientific adventurer, 96

William J. L. Sladen, 96, who gave up a medical career to begin a new one as a zoologist, died Monday at his home in Warrenton, Va.

He was an internationally known authority on birds, and his exploits were dramatized in the 1996 Hollywood film Fly Away Home and chronicled in the pages of National Geographic.

Dr. Sladen was part scientist, part conservationist, part adventurer. He 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.

Once, after a fire destroyed his base hut and killed his fellow travelers, he spent 17 days alone with no shelter but a tent, according to his family. For periods, he subsisted on the meat of penguins and cormorants, another aquatic bird.

Dr. Sladen's research helped reveal the intrigue of Antarctic wildlife. 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 perhaps most popularly known for his effort, undertaken with the Canadian artist and pilot William Lishman, to teach Canada geese a migratory route from Ontario to the Airlie conference center in Warrenton using an ultralight 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 Dr. Sladen served as a technical adviser, featured a father-daughter duo who take on a similar project. - Washington Post