Chris Murray, the D.C. Audubon Society’s president, spots a bird during the annual Christmas Bird Count at Battery Kemble Park on Saturday. (Salwan Georges/The Washington Post)

Saturday morning’s deluge may have broken records for the Washington region, but it did not stop a group of 30 intrepid nature lovers from converging in the muddy entrance to Battery Kemble Park just after dawn.

With rain hoods over their heads and binoculars around their necks, they listened as Chris Murray, president of the D.C. Audubon Society, prepared them for the task at hand: to find and count as many birds as they possibly could.

“This is where we find out who the real birders are every year,” Murray said to the group.

They had gathered for the Audubon Society’s annual Christmas Bird Count, which invites dedicated birdwatchers to trek through their communities to collect data about bird species and their habitats.

What began in 1900 as an alternative to hunting birds around the Christmas holiday has become the nation’s longest-running community science bird project, providing scientists with crucial information about the health and migrations of bird populations across North America.

But for one of the birdwatchers in the crowd, community counts such as this one across the country have become more important than ever.

Brooke Bateman, a senior climate scientist with the National Audubon Society, studies how North American birds are migrating — and in some cases, dying — as a result of climate change. Based in New York, Bateman took part in the District’s Christmas Bird Count for the first time in the hopes of learning about shifts in the D.C. bird population from longtime local birdwatchers.

“We’re already seeing that some species are leaving areas that are becoming worse because of climate change, and moving into areas that are becoming better,” Bateman said.

A 2014 report from the National Audubon Society, a nonprofit group that advocates for birds, painted a grim picture, predicting that global warming will threaten the survival of more than half of all species of birds in North America.

The Washington area faces particularly dire threats, with increasingly scorching summers, milder winters and intensifying rainfalls. These drastic climate changes could in turn force bird populations to move to more suitable regions. The oriole, Maryland’s state bird, could abandon the Mid-Atlantic region by 2050 seeking cooler temperatures, the Audubon report said. The District’s official bird, the wood thrush, could also be forced to migrate to cooler climates.

Other birds common across the continent, such as the chipping sparrow, may start concentrating in the District more as the winters get warmer, and some species, including robins, may stick around longer, migrating less during the winter, Bateman said.

Because they’re highly visible, birds are important messengers for scientists, Bateman said.

“They’re sort of like this barometer of change,” she said. “They’re letting us know that things are not the same, and climate change is happening now.”

The Christmas Bird Count therefore is essential to adding data to scientists’ understanding of climate change, she said.

“People like this that are willing to come out in the rain and look for birds . . . this is how I’m able to do my science, because people care this much,” Bateman said.

As the group trekked around the park Saturday morning, eyes glued to binoculars, the birds seemed quiet and hidden at times, hunkered down in the pouring rain. But only a few minutes into the hike, Bateman saw a flash of red and heard a faint but familiar “chip, chip chip.”

“A female cardinal just landed in there,” she said, pointing to a tree in the distance. “She’s somewhere in there.”

Then, others in the group spotted a flock of robins flying in the distance. Andrés Anchondo, who was tasked with keeping track of the count, estimated there were about 40 in the flock.

After carefully inching down a slippery hill, Margaret Everson leaned in close to her two daughters, ages 6 and 8, the youngest birdwatchers in the group.

“You hear that? I hear four birds right now,” Everson said. “Close your eyes and listen to all of them.”

Bateman spent most of the hike picking the brains of veteran birdwatchers, such as Carol Stoel, who has lived in the District for more than 50 years and has loved birds since she was a young girl fixated on her parents’ backyard bird feeder.

“The summers are much worse than they used to be,” she told Bateman. Stoel worries about her grandchildren as the planet continues to heat up. She’s grown frustrated by what she sees as the “unwillingness of the government to take action.” But she feels heartened by the growing interest in bird count events such as this one.

“It’s been such a slow wait for people to wake up,” Stoel said as her drenched boots crunched down on leaves alongside a creek.

By the end of a hike that lasted more than two hours, the group counted 18 species of birds, down from last year’s 23 species in the park. Across the Washington area last year, the Christmas Bird Count tracked 106 species. The Audubon Society takes into account rain, the number of people counting and other factors in its totals.

After trudging through a deep puddle of water and mud, the counters reached a brick house surrounded by bird feeders — an annual mecca for the bird count.

“Goldfinches,” Murray said to the group, pointing at the highest bird feeders as the group looked through their binoculars from across the road.

“How many goldfinches are there?” said Radha Neelakantan, who was tracking the birds on eBird, an application that collects bird data.

“I counted two,” Murray said.

For Neelakantan, bird counting is “like a treasure hunt and a puzzle put together.”

“You’re trying to find something, and then once you find it, you’re trying to figure out what it is and putting together the little clues and the little pieces,” Neelakantan said. “It’s always a challenge.”

“Have you thought about at all how it relates to climate change?” Bateman asked her as they walked back toward the parking lot.

The question seemed to catch Neelakantan by surprise. She had never really thought of the bird count as a predictor of climate change. And Bateman said that was perfectly okay.

“A lot of people get into birding just because they love birds,” Bateman said.