Flight plans: BirdCast helps us look at bird migration from an entirely different angle

April 25, 2023

Up to 3.5 billion birds and more than 600 species migrate across North America each spring—mostly at night—but usually we can see them only looking up from the ground. BirdCast enables us to look down from above, and that changes everything, reports The New York Times.

A joint project of the Cornell Lab of Ornithology, Colorado State University, and U. Mass Amherst, BirdCast is a website that lets us see them from a vantage point hundreds of miles above Earth, capturing each night’s continental migration as collected by over 140 radar stations across the country—data gathered about birds on the wing. The site went live to the public in 2018.

Ty Burr, a Times writer, discovered BirdCast through a friend and fellow birder he calls Hardcore Jim, “because he’s the kind of guy who takes online courses in sparrows.”

On BirdCast, Bur says, “from sunset to sunrise, a mosaic image is made every 15 minutes or so from radar data that has been collected and algorithmically sifted to separate the passage of birds overhead from weather events, bats, insects and other airborne objects; then, gathered into a continental map that sweeps in a loop, the ornithological commute shifting from a muted purple to an all-hands-on-deck neon yellow as the numbers increase.”

There’s not a lot to look at in, say, February. In April and May, the map’s a rainbow of arrival, a feathery procession as brilliant as a pride parade.

Conceptually, the site is more than a little breathtaking. If birding on the ground gives you the micro of individual species and individual birds, BirdCast provides an unexpected macro perspective that functions as both science and art, number-crunching and airborne prayer. Last year, the team behind the site introduced a Migration Dashboard that allows users to search by state and county, so you can see who flew over your head last night and, based on previous years’ arrivals, have a good guess as to who will be hanging around your woods in the morning. (Since the technology is not good at identifying individual species, researchers rely on local birders, felicitously known as “ground-truthers,” to flesh out their data.)

Even without the local angle, BirdCast prompts a radical reconsideration of bird behavior, global processes, and our stake in and responsibilities toward both. The sheer numbers that BirdCast records prompt us to ask: What do we owe these temporary neighbors as they stream through? Do we crowd into the nearest park just to have a look? Or do we turn out the lights to save their lives?

To Burr, “the nightly BirdCast map has come to mean a great deal—not least a corrective to our human-centric view of the planet.”

BirdCast reorients us in both space and time, he says. “It shifts our understanding of ecosystems from the narrow—the street, the neighborhood, the town—to a vast globe that birds traverse twice a year because they must. Looking at that ceaseless neon flow forces a viewer to acknowledge patterns that long predate our appearance on the stage and, unless we succeed in our drive to kill everything on the planet, could long outlast us.

“Within this epoch the thing that matters—a bird setting out on a journey a thousand miles long, not data but feather and bon—is still here.”

Research contact: @nytimes