UMCES Research Finds Climate Change and Species Declines Are Reshaping Communities of Migrating Birds

Research conducted at University of Maryland Center for Environmental Science’s (UMCES) Appalachian Laboratory recently found that changes in songbirds’ abundance and migration timing — often a consequence of climate change and habitat disturbances — are causing dramatic shifts in which bird species are commonly seen together during migration. By showing how species-level processes can change an entire community, this research encourages a multi-species approach to understanding and conserving migratory birds.

With funding from the National Science Foundation, Joely DeSimone, a postdoctoral research scientist at UMCES, and Emily Cohen, an associate professor at UMCES (and member of the Maryland Wildlife Advisory Commission), analyzed data from over 700,000 birds captured at five stopover sites over the past 50 years. They found that species-specific changes in timing and abundance are associated with sometimes dramatic changes in co-occurrence, bringing together new groupings of species and splitting up species that used to commonly co-occur, ultimately changing the bird communities at some of these sites. 

“In response to climate change and other disturbances, many migratory bird species have been declining and changing the timing of their migrations,” DeSimone said. “But these changes vary across species. Some species are migrating earlier, others are migrating later. Some species are declining, others increasing. We wondered how these many different species-level changes might add up and change the entire stopover community.”

Previous research from this team showed that songbird species take part in consistent social relationships when they rest and refuel in “stopover” habitats during migration, forming communities. UMCES is one of the only institutions examining migrating birds in the context of their communities. Their research confirms that conservation issues impacting one species have the potential to ripple throughout an entire community, perhaps changing the types of interactions species participate in.

“Following animals on the move is complicated and one thing we don’t know much about is how migrating species influence the success of each other’s journeys,” Cohen said. “They might be competing with each other for limited food sources along the way and, at the same time, they might be listening to each other to find the safest or fastest route. While we don’t know what these changes in co-occurance mean for migrating birds, as species continue to decline, it feels urgent to find out.”