For many, the sight of a red-breasted robin pulling worms from the ground is a sure sign of spring. Conventional wisdom holds that robins fly south for the winter and return north as the temperatures warm up.
That’s not always the case, says Alex Jahn, a migration specialist with the Environmental Resilience Institute at Indiana University. Jahn studies bird migration patterns to see how they might shed light on environmental changes.
Before coming to IU in 2018, Jahn worked for more than a decade studying the migratory patterns of birds in North and South America. He also worked for two years at the Smithsonian Migratory Bird Center in Washington, D.C. There, he noticed the large number of robins flying around the city and thought studying
a common backyard bird might offer information about environmental changes in our midst.
To understand the migration patterns of local robins, Jahn has begun using tiny GPS harnesses—little bird “backpacks”—to gather data on their movements.
While it’s not uncommon for researchers to attach GPS units to larger birds and other animals to track their movements, Jahn says GPS harnesses for small birds are relatively new because the units have to be so tiny. They weigh only about 2.4 grams. “It’s hard to miniaturize the battery,” Jahn explains. “But that has improved over the last five years and now we can use them on these small songbirds.”