The 120th 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.

A September study published in the journal Science found that nearly 3 billion birds have disappeared on the continent since 1970. And an October Audubon report found that two-thirds of birds in North America are at risk due to warming temperatures and human impact on the planet.

Information gathered from the CBC will help scientists pinpoint priority areas for conservation efforts. New this year, volunteers are also being asked to upload photos and short anecdotes during the bird count in real time.

"The Christmas Bird Count is a great tradition and opportunity for everyone to be a part of 120 years of ongoing community science," said Geoff LeBaron, Audubon’s Christmas Bird Count director, in a news release. "Adding your observations to twelve decades of data helps scientists and conservationists discover trends that make our work more impactful. Participating in the Christmas Bird Count is a fun and meaningful way to spend a winter day for anyone and everyone."

Last year's findings

two northern bobwhite quail Bird-watchers can keep an eye out for the declining northern bobwhite, the only native quail in the eastern U.S. (Photo: Steve Maslowski/USFWS [CC BY 2.0]/Flickr)

For the 2018 count, 79,425 observers tallied more than 48.6 million birds belonging to 2,638 species.

Although the number of human participants was at a record high, the total numbers of birds tallied over the past 33 CBC seasons has dropped dramatically. In 2018, it was 10 to 20 million birds short of the average numbers counted through the past 20 seasons.

"For years it has been mentioned in the annual Christmas Bird Count summaries that we shouldn't worry too much about the total number of birds each season, as it can vary tremendously depending upon whether winter roosts of blackbirds, crows, or robins happen to be within count circles," LeBaron writes.. "But still, especially in light of the recent paper published this fall about diminishing numbers of birds across the continent, this disturbing trend deserves some future analyses."

Newly spotted for the U.S. in 2018 was a great black hawk near Portland, Maine, and a little stint in San Diego. A fish crow in Hamilton, Ontario, was a new addition to the all-time Canadian species list.

Researchers found that the northern bobwhite, the only native quail in the eastern U.S., continues its downward spiral. Due to loss of habitat exacerbated by droughts, the species faces massive declines. However, red-breasted nuthatches and purple finches had major irruptions and were found in large numbers far from their normal ranges.

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.

Mary Jo DiLonardo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.

Christmas Bird Count takes off Dec. 14
Grab your binoculars and help scientists study bird populations in the 2019 edition of the world's longest running citizen-science survey.