Every winter, a group of avian enthusiasts collect data on local bird populations for the Audubon Society of Western Pennsylvania. The Christmas Bird Count is the oldest citizen science project in the world, and it is returning to Pittsburgh on Dec. 30.
The information gives experts some insight into how climate change and habitat loss affect some bird species.
"We can go back from a year-to-year basis and make some observations on what's happening with various bird populations," said Chris Kubiak, education director or the Audubon Society of Western Pennsylvania.
The count is done on Christmas for two reasons, according to Kubiak.
The Christmas Bird Count was founded in 1900 as a reaction to "side hunts," a sporting tradition where teams competed to see how many birds they could shoot and collect. Environmentalist Frank Chapman saw a more sustainable alternative in bird watching.
Kubiak said the count is also done around Christmas to see how residents species are doing during the non-breeding season compared to breeding bird surveys done in the summer.
"Every year we get a window into how our local bird species are doing here in western Pennsylvania," Kubiak said.
Wild turkeys, red-tailed hawks and red-bellied woodpeckers are local species that have boomed in recent years, according to Kubiak, while American black ducks and horned larks have declined in population.
Kubiak said about 180 people participated in Pittsburgh's Christmas Bird Count last year, and the event is open to birders of all levels.
Information on how to join the Christmas Bird Count is available at the Audubon Society of Western Pennsylvania website.