Bridget Stutchbury, biology professor at York University in Toronto, Canada, knows big things come in small packages. Stutchbury, her students and research associates began attaching tiny (1.1 gram) geolocators to purple martins and wood thrushes back in 2007. These dime-sized backpacks designed by the British Antarctic Survey are held in place at the base of the birds spine by thin straps looped around its legs. According to Stutchbury, the backpacks do not interfere with flight nor the birds regular routine and/or habits.
Stutchbury and her researchers attached the geolocators to 14 wood thrushes and 20 purple martins on their breeding grounds in Pennsylvania in 2007. In the summer of 2008, they recovered backpacks from five wood thrushes and two purple martins. The geolocators record light levels. Researchers can analyze the light data and estimate the birds latitude and longitude to within 180 miles at any given time.
At first glance, plus or minus 180 miles may not seem like pinpoint accuracy but when you figure youre tracking a mobile eight-inch object over a linear distance of 4,000 miles and you can not only estimate its location but determine the direction of its movement, its pretty amazing.
And the results, like a 200 mph peregrine falcon stoop, have plunged the sometimes-staid ornithological world into dizzying new territory. Stutchbury told Science Watch in a recent (Sept. 2010) interview, Until our study, researchers relied almost entirely on short distances or time frames to understand songbird migration. The ability to track small birds over their entire flight, which can amount to a trip of over 15,000 km per year for the bird, is a revolution in animal ecology and allows researchers to discover amazing new facts about migration speed and strategy.
Stutchbury noted that researchers have dramatically underestimated songbird migration flight performance. She told SW that previous, traditional methods of estimating migration-flight distances reported an average of 93 miles per day. The geolocators have shown that the birds can fly in excess of 300 miles in a single day.
Stutchburys research also shows quite a difference between spring and fall migration. One purple martin that sauntered down to Brazil in 43 days returned to its breeding colony in Pennsylvania in a blistering 13 days, averaging more than 300 miles per day.
The relevancy of this new technology cannot be overestimated. Many species of Neotropical migrants are experiencing precipitous population decline. Stutchbury told SW, Knowing where breeding populations spend the winter, and vice versa, is critical for focusing conservation efforts in regions where they are needed most, and for establishing new and more effective international partnerships in migratory songbird conservation.
Stutchbury and her researchers attached the geolocators to 14 wood thrushes and 20 purple martins on their breeding grounds in Pennsylvania in 2007. In the summer of 2008, they recovered backpacks from five wood thrushes and two purple martins. The geolocators record light levels. Researchers can analyze the light data and estimate the birds latitude and longitude to within 180 miles at any given time.
At first glance, plus or minus 180 miles may not seem like pinpoint accuracy but when you figure youre tracking a mobile eight-inch object over a linear distance of 4,000 miles and you can not only estimate its location but determine the direction of its movement, its pretty amazing.
And the results, like a 200 mph peregrine falcon stoop, have plunged the sometimes-staid ornithological world into dizzying new territory. Stutchbury told Science Watch in a recent (Sept. 2010) interview, Until our study, researchers relied almost entirely on short distances or time frames to understand songbird migration. The ability to track small birds over their entire flight, which can amount to a trip of over 15,000 km per year for the bird, is a revolution in animal ecology and allows researchers to discover amazing new facts about migration speed and strategy.
Stutchbury noted that researchers have dramatically underestimated songbird migration flight performance. She told SW that previous, traditional methods of estimating migration-flight distances reported an average of 93 miles per day. The geolocators have shown that the birds can fly in excess of 300 miles in a single day.
Stutchburys research also shows quite a difference between spring and fall migration. One purple martin that sauntered down to Brazil in 43 days returned to its breeding colony in Pennsylvania in a blistering 13 days, averaging more than 300 miles per day.
The relevancy of this new technology cannot be overestimated. Many species of Neotropical migrants are experiencing precipitous population decline. Stutchbury told SW, Knowing where breeding populations spend the winter, and vice versa, is critical for focusing conservation efforts in regions where they are needed most, and for establishing new and more effective international partnerships in migratory songbird conservation.
Keeping Track Of Purple Martins