(Mary Schuermann Kuhlman/Indiana News Service)  If you want to contribute to more than a century of science about the feathered friends in your community, the Audubon Society’s 120th Christmas Bird Count is under way.

In designated areas of Indiana, volunteer groups are spanning out over a 15-mile radius and counting every bird they see or hear.

Brad Bumgardner, executive director of the Indiana Audubon Society, explains it began in 1900 and now is the longest running census of wildlife in the world.

“It was a tradition to go out on Christmas Day and shoot every bird you saw, and a guy by the name of Frank Chapman said, ‘You know, instead of shooting them all, why don’t we count them instead?'” Bumgardner relates. “And since then, 120 years later, it’s being done worldwide.”

Indiana’s 2018 included several bird species with record high counts including black vulture, golden eagle, snowy owl, red-bellied woodpecker, winter wren and fox sparrow. The bird count began over the weekend and events are scheduled through Jan. 5.

The counts are used to study the long-term health and status of bird populations across North America, helping to inform strategies to protect birds and their habitats.

Bumgardner says species come and go over the decades, which can happen with changes in land use or climate change.

“So things such as winter finches were much more abundant in Indiana in the 1970s and early ’80s, and a lot of them just aren’t moving as far south now as they’re looking for food supplies,” he states.

A recent study found that more than 3 billion birds have been lost in North America in the past 50 years.

Another study found North American migratory birds have been getting smaller, and their wingspans wider, over the past four decades – changes attributed to a warming climate.