Songbirds Found to MigrateFour Times Faster Than Earlier Estimates

By attaching tiny geolocators on the backs of purple martins and wood thrushes, researchers have discovered that some songbirds can fly up to 358 miles per day on their spring migrations, four times faster than previous estimates of 93 miles per day. The study, conducted by Bridget Stutchbury of York University in Toronto and published in Science, marks the first time that scientists have been able to track songbird migration routes to the tropics and back, and Stutchbury and her colleagues were stunned by the results. One purple martin completed the migration from the Brazilian Amazon to Pennsylvania — a trip of roughly 4,500 miles — in just 13 days. A wood thrush made the trip from the Yucatan Peninsula to Pennsylvania — a trip of roughly 2,500 miles — in just two weeks. The geolocators, attached to 20 purple martins and 14 wood thrushes in 2007, showed that the birds traveled far more rapidly on the southerly spring migrations than on the return migration in the fall. Stutchbury and her colleagues used miniature geolocators, which weigh 1.5 grams, or 1/20th of an ounce. By continuously measuring light, the geolocators allow researchers to estimate the birds’ latitude and longitude over time.