Posted on behalf of Roberta Kwok

Tiny geolocating “backpacks” have helped scientists discern that songbirds can migrate three times as fast as previously thought, as reported in Science.

Researchers attached the devices, which track the timing of sunrise and sunset each day and therefore enable researchers to estimate latitude and longitude, to 14 wood thrushes and 20 purple martins in Pennsylvania by looping straps around the bird’s legs (Washington Post). The following summer, the team recaptured seven birds and used the geolocation data to determine their migratory paths.

Two birds flew 2500 kilometres in 5 days on their southbound trip to the Yucatan Peninsula, while previous studies had estimated songbird migration speeds at less than 150 kilometres per day. One female purple martin clocked 577 kilometres per day as she sped northward from the Amazon basin in the spring, covering 7500 kilometres in 13 days. Spring return times were two to six times faster than fall migrations, possibly because the birds were racing to nab good breeding sites (Los Angeles Times).

“We were flabbergasted by the birds’ spring return times,” says co-author Bridget Stutchbury, a biologist at York University, Canada (BBC).

This is the first time that scientists have been able to track songbird migration over such long distances, Stutchbury says (BBC). Miniature geolocators have been used to follow migrations before, but only on larger birds such as gulls (LA Times).

“The data are exciting. It makes me drool,” Peter Marra, an ornithologist at the Smithsonian Migratory Bird Center at the National Zoo in Washington, told the Times.

Stutchbury ’s team tagged another 20 purple martins and 35 wood thrushes with geolocators last year and plans to get more data in spring (Post).

More images and video on the press release.

Photo: male wood thrush wearing geolocator backpack / Elizabeth Gow