Treehugger Tuesday

From National Audubon:

These Beloved Warblers Migrate North Almost a Week Earlier Than 50 Years Ago
By Kevin Wheeler
Editorial Intern, Audubon Magazine
February 21, 2020


Black-throated Blue Warblers have shifted the timing of their spring and fall migrations over the past fifty years.
Photo: Kyle Horton

If you’ve spent much time observing the seasonal comings and goings of your backyard birds, you may have noticed some favorite species returning a little earlier in spring than they used to. No, your eyes do not deceive you—a new study on Black-throated Blue Warblers adds to a growing wealth of research showing that the timing of bird migration is indeed changing.

These neotropical warblers make an annual spring journey that spans 3,000 kilometers, from Central America to the eastern deciduous and boreal forests of North America. And it now starts about 5.5 days earlier than it did in the 1960s—a rate of around one day per decade, according to the study, published this week in the journal The Auk: Ornithological Advances. The researchers reached that conclusion by analyzing around 150,000 bird-banding records from the U.S. Geological Survey between 1965 and 2015.

While most migration research has focused on spring, the new study also examined trends in fall migration. “And with fall migration, we found that the peak of the migratory season is not changing, but early fall migration is getting earlier and late fall migration is getting later, which means a whole migratory season overall is getting longer,” says lead author Kristen Covino of Loyola Marymount University.

Read the entire article here