If you happened to look up at the Virginia sky one morning last December, you might have noticed an odd sight: 10 Canada geese honking and flapping in crates suspended from a helium balloon.
The geese were not learning how to fly — they already knew that. They were supposed to be studying the ground below them so they could remember the route when spring came.
While small birds like robins and warblers know their traditional migration routes by instinct, large birds like geese have to be taught them. Although Canada geese are not endangered, the 10 geese were part of an experiment aimed at helping threatened species like trumpeter swans and whooping cranes to learn migration routes. When threatened species are reintroduced to a new area, it can take several seasons — and many deaths — for them to figure out the new migration route on their own. Teaching them could save time and lives.
"What we're trying to do is teach them a safe, predetermined migration route of our choice," said wildlife researcher William Sladen. "They can learn passively by just looking out."
Continuing the Work of 'Father Goose'
Sladen is director of Environmental Studies at Airlie, a research center in northern Virginia that is home to scores of swans and other waterfowl. The balloon flight was only his latest attempt to teach birds to migrate. He had earlier worked with Canadian sculptor Bill Lishman, who pioneered such flights using powered hang gliders known as microlights.
Lishman, who is known as "Father Goose," was the first human being ever to lead a flock of geese on a migration route. He developed a technique in which he raised young geese to identify with him as their parent, then used the bond to make them follow him when he took to the air in a microlight.
At his home in Ontario, Canada, Lishman first hatched geese in an incubator. Then he relied on a natural phenomenon called "imprinting," in which recently hatched birds believe the first moving object they see is their parent. The bond was strong enough that they would fly behind his microlight for hundreds of miles, tracing migration routes to the south.
The process was time-consuming, because it required raising birds from birth, bonding them with a single human individual, then training them to fly behind a microlight. Lishman, who was the inspiration for the 1996 movie Fly Away Home, had to raise his birds with the care of a loving parent.
Finding a New Way
Working with the Sky Calypso Society, a nonprofit developing ways to use balloons and airships for environmental protection, Sladen is hoping to find a method that is less time-consuming and could be used to train more birds to migrate. The main aim of the balloon experiment is to see whether birds can learn a migration route passively by being carried over it in crates, rather than actually flying the route themselves behind a microlight. If the experiment is successful, Sladen hopes to use airships to teach large numbers of threatened birds to migrate.
After careful consideration of weather patterns and wind conditions, Sladen and his team chose Dec. 22 as the day of the launch. On a chilly Saturday morning, a helium balloon carrying 10 geese in two crates lifted off from a polo field near Sperryville, Va.