A New Study Finds That Bird Migration Begins Earlier Each Spring
When spring rolls around each year, you can almost always guarantee a few things: Flowers begin blooming again and birds start migrating back to where they came from before winter's chilly temperatures set in. But when birds fly back home isn't actually set in stone. According to Science Daily, Kristen Covino, a lead researcher from Loyola Marymount University, and her colleagues used data from 1965 to 2015 to analyze migration patterns for Black-Throated Blue Warblers, and they found that this species has been migrating earlier and earlier each spring.
As part of the study, which was just published in The Auk: Ornithological Advances, the researchers dug into about 150,000 records from the USGS Bird Banding Laboratory to look at the timing of this bird's migratory patterns during the springtime. With 50 years of data to review, the researchers discovered that Black-Throated Blue Warblers' migration appeared to start about one day earlier every 10 years. These findings also helped them discover that the there were no migration changes during the fall, meaning only their springtime return has changed. That being said, researchers did notice that the birds' autumn travel appears to take longer now than it did when data was first recorded in 1965.
Why did researchers choose to study these birds in the first place? "We selected Black-Throated Blue Warblers because it's relatively straightforward to determine their age and sex, which means that the data this species generates are both accurate and powerful," Covino shared.
While these findings provided more details about bird travel patterns, the researchers believe that even more studies should be done in order to better understand birds and their migration habits. "More studies of these patterns of fall migration timing and, even more so, both spring and fall migration timing across years are needed to gain the complete picture of how species are changing migration timing," Covino said.