A York University researcher has tracked the migration of songbirds by outfitting them with tiny geolocator backpacks – a world first – revealing that scientists have underestimated their flight performance dramatically.
“Never before has anyone been able to track songbirds for their entire migratory trip,” said study author Bridget Stutchbury, a professor of biology in York’s Faculty of Science & Engineering. “We’re excited to achieve this scientific first.” Songbirds, the most common type of bird in our skies, are too small for conventional satellite tracking.
Stutchbury and her team mounted miniaturized geolocators on 14 wood thrushes and 20 purple martins, breeding in Pennsylvania during 2007, tracking the birds’ fall takeoff, migration to South America, and journey back to North America. In the summer of 2008, they retrieved the geolocators from five wood thrushes and two purple martins and reconstructed individual migration routes and wintering locations.
Data from the geolocators indicated that songbirds can fly in excess of 500 km (311 miles) per day. Previous studies estimated their flight performance at roughly 150 km (93 miles) per day.
The study found that songbirds’ overall migration rate was two to six times more rapid in spring than in fall. For example, one purple martin took 43 days to reach Brazil during fall migration, but in spring returned to its breeding colony in only 13 days. Rapid long-distance movement occurred in both species, said Stutchbury.
“We were flabbergasted by the birds’ spring return times. To have a bird leave Brazil on April 12 and be home by the end of the month was just astounding. We always assumed they left sometime in March,” she said.