Crowdsourcing, for the Birds

“As soon as the heat maps began to come out, everybody recognized this is a game changer in how we look at animal populations and their movement”

On a warm morning not long ago on the shore of a small prairie lake outside this state capital, Bob Martinka trained his spotting scope on a towering cottonwood tree heavy with blue heron nests. He counted a dozen of the tall, graceful birds and got out his smartphone, not to make a call but to type the number of birds and the species into an app that sent the information to researchers in New York.

Mr. Martinka, a retired state wildlife biologist and an avid bird-watcher, is part of the global ornithological network eBird. Several times a week he heads into the mountains to scan lakes, grasslands, even the local dump, and then reports his sightings to the Cornell Lab of Ornithology, a nonprofit organization based at Cornell University.

“I see rare gulls at the dump quite frequently,” Mr. Martinka said, scanning a giant mound of bird-covered trash.

Tens of thousands of birders are now what the lab calls “biological sensors,” turning their sightings into digital data by reporting where, when and how many of which species they see. Mr. Martinka’s sighting of a dozen herons is a tiny bit of information, but such bits, gathered in the millions, provide scientists with a very big picture: perhaps the first crowdsourced, real-time view of bird populations around the world.

Birds are notoriously hard to count. While stationary sensors can measure things like carbon dioxide levels and highway traffic, it takes people to note the type and number of birds in an area. Until the advent of eBird, which began collecting daily global data in 2002, so-called one-day counts were the only method.

While counts like the Audubon Christmas Bird Count and the Breeding Bird Survey bring a lot of people together on one day to make bird observations across the country, and are scientifically valuable, they are different because they don’t provide year-round data.

And eBird’s daily view of bird movements has yielded a vast increase in data — and a revelation for scientists. The most informative product is what scientists call a heat map: a striking image of the bird sightings represented in various shades of orange according to their density, moving through space and time across black maps. Now, more than 300 species have a heat map of their own.

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