Birds get more efficient the more they migrate
© Operation Migration USA Inc.; Photographer: Joe Duff
Here’s a lesson on road trips from whooping cranes: For efficient migration, what matters is the age of the oldest crane in the group. These more experienced fliers nudge youngsters away from going off course on long flights.
“The older birds get, the closer they stick to the straight line,” says ecologist Thomas Mueller of the University of Maryland in College Park, who crunched data from 73 Grus americana migrating between Wisconsin and Florida.
One-year-olds traveling with other birds of the same age, the analysis says, tend to deviate about 76 kilometers from a direct route. But if they fly in a group with an 8-year-old crane, they stray 38 percent less, or about 47 kilometers, Mueller and his colleagues report in the August 30 Science.
Eight years of data on these endangered cranes summering in Wisconsin’s Necedah National Wildlife Refuge offered a rare chance to