Search Here

Scientists from The Cornell Lab of Ornithology built up a migration map including 188 bird species in the Western Hemisphere. Their annual actions, migrations and movements have been caught, with the study showing the similarities in their routes, even as the patterns were captured in the unique "animated" map.

"We used millions of observations from the eBird citizen-science database," Frank La Sorte, lead author of the study, said in a press release. "After tracing the migration routes of all these species and comparing them, we concluded that a combination of geographic features and broad-scale atmospheric conditions influence the choice of routes used during spring and fall migration."

Some of the findings were interesting. One observation said the species that fly over the Atlantic Ocean and touch the Caribbean and South America in the fall season take a clockwise loop. But while they wing their way back during spring, they fly inland.

Some of the bird species following this route include bobolinks, Cape May warblers and Bicknell's thrush.

"These looped pathways help the birds take advantage of conditions in the atmosphere," La Sorte said. "Weaker headwinds and a push from the northeast trade winds as they move farther south make the fall journey a bit easier. The birds take this shorter, more direct route despite the dangers of flying over open-ocean."

Even though the spring migration path is convoluted and roundabout, the birds fly fast because of the strong tailwinds transporting them north to breeding grounds. But for other species that do not fly over the open oceans, the study shows that spring and fall migration routes are the same.

"It's an exciting new area of research," La Sorte said. "By using eBird data and other forms of migration tracking information, we're getting a more detailed picture than ever before about where and when birds migrate. That's the kind of information we need to make smart conservation decisions for species that live in vastly different regions during the year. Citizen science makes it possible to do this for populations across an entire hemisphere."

The findings were published in the Jan. 20,2016 issue of the Proceedings of the Royal Society B: Biological Sciences.