Drawing up conservation plans for migratory birds can be complicated—the suckers just don’t stay put. But now for the first time, scientists from the Cornell Lab of Ornithology have a complete picture of an entire year’s worth of movement for 118 species throughout the Western Hemisphere. That’s a lot of flapping wings.

The analysis was published recently in the Proceedings of the Royal Society B, and the researchers couldn’t have done it without citizen scientists. To make the map, the ornithologists plotted millions of individual observations from the site eBird, where birders are able to log everything they spot though their binoculars in real time.

Looking at all the birds’ itineraries together allowed some broad patterns to emerge. For example, species that take a direct route south over the Atlantic Ocean during the fall tend to loop back clockwise and fly inland during the spring. This helps them take advantage of the strong winds blowing in each season, which makes their long journeys fly by faster. Ornithologists hope the new dataset will improve avian conservation, because the first step towards protecting any species is knowing where it is—and where it’s going.

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