The 119th annual Christmas Bird Count or CBC begins Dec. 14, and scientists are relying on more than 70,000 volunteers to help them gather data about birds across the Western Hemisphere.

Each year, Audubon mobilizes experienced bird-watchers and amateurs alike to participate in the world's longest-running citizen science survey.

The CBC helps ornithologists study the fluctuation, range and movement of bird populations across the continent, enabling them to better understand how bird species are faring.

Audubon scientists have analyzed 30 years of climate data and tens of thousands of CBC bird observations to study how climate change affects bird populations.

Their 2014 report found that 314 of 588 bird species are at risk of being climate threatened, and some species could lose more than 50 percent of their range by 2080.

Information gathered from the CBC will help scientists pinpoint priority areas for conservation efforts.

“It’s never been easier to be a citizen scientist and it’s never been more important to be one,” said David Yarnold, president and CEO of the National Audubon Society, in a news release. “Birds and the people who watch them are noticing changes. Using the data gathered by more than a century of Christmas Bird Counts, Audubon will keep protecting birds and the places they need. I’m incredibly proud of the volunteers that contribute to this tradition.”

In 2017's CBC, 76,987 observers tallied over 59 million birds belonging to 2,673 species.

One disturbing finding from 2017's count was the continued decline of the northern bobwhite, the only native quail in the eastern United States. The Eurasian collared-dove was observed crossing the continent and eight were spotted in Alaska.

The Christmas Bird Count runs through Jan. 5. For more information and to find a count near you, visit Audubon's website.

Editor's note: This article has been updated since it was originally published in December 2015.

2018 Christmas Bird Count takes off Dec. 14
Grab your binoculars and help scientists study birds populations in the world's longest-running citizen science survey.