Scientists use crowdsourcing to map bird migrations

Researchers use data from eBird to find migration pathways

For me, the sight of Townsend’s warblers off my balcony or the yellow-rumped warblers in our canyons are reminders that the days will grow shorter and the nights will be cooler. And cliff swallows constructing their mud nests under the eves of the buildings where I work let me know that it’s springtime.

These birds migrate with the seasons. I’m not unusual in my observations. Just about everybody notices birds migrating in and out of their neighborhoods. Although these are common experiences, much has remained unknown about bird migrations. We may know that certain species of birds migrate between a summer nesting region and a place where they spend their winters, but the exact paths that many of them take have remained as mysteries. About 73 percent of North American birds are migratory, of those, slightly more than half are birds that migrate very far, to the arctic regions or to the tropics.

Using data from eBird and other sources, scientists have now been able to map the migration paths of a dozen North American birds. This knowledge can greatly enhance conservation efforts. For example, knowing the pathways of bird species may help to determine which windmill generators need to be powered down during certain times of the year to avoid collisions with birds. We might also better understand which wetlands or watersheds lie in a migratory pathway, letting us know which ones need priority in being restored.

For animals, migration is the seasonally associated movement from one place to another, usually between a wintering territory and a breeding territory.¹ For example, the cute cliff swallows that build their mud nests where I work have their babies here in North America in spring and summer, then migrate to winter in South America. Lots of bird species migrate, and lots of other animals, including mammals, amphibians, fish, crustaceans, and insects migrate as well.