The morning started out a disaster. We were prepared to go rain or shine, but Saturday’s ice storm made conditions not just unpleasant, but dangerous. I frantically coordinated with my colleagues at the D.C. Audubon Society to alert our 24 volunteers that we had to push our start time to the afternoon. Postponing any longer or giving up was out of the question, after all, because we had more than a century’s worth of tradition to uphold.

The first Christmas Bird Count, or CBC, was held in 1900, when ornithologist Frank Chapman of the newly formed Audubon Society proposed a twist on traditional Christmas “side hunts,” where hunters competed to see who could shoot the most birds in a day. Many species of birds were threatened by overhunting at the time — egrets were nearly driven to extinction because their long plumes were used to decorate hats — and Chapman proposed simply counting the birds instead of killing them.

Twenty-seven birders in 25 locations across the country participated in that first Christmas Bird Count. This year’s 117th annual count expects more than 72,000 participants in more than 2,500 locations in the Western Hemisphere, from Tierra del Fuego to the Arctic Circle. Last year people counted almost 60 million birds. It’s the longest-running wildlife census in the world and one of our most valuable sources of information about birds.

Our small sliver of the D.C. Christmas Bird Count covered Battery Kemble Park in Northwest Washington. Just three of our original 24 sign-ups made it to the new start time, joining three D.C. Audubon volunteer board members, Chris Murray, Sara Fuentes and me. It was the first CBC for each of the attendees, Laysa Hedjar, Katherine Youngbluth, and Hisao Yatsuhashi, so I explained the situation: We were part of a larger effort trying to identify and count every individual bird within a 15-mile-diameter circle around Washington. At the end of the day, the counts from each sector of the circle would be tallied together to get a sense of the total avian population in the area. Our local count in turn would be added to the pool of national and international results to get a picture of bird population trends over time.

Our mission set, and our coats zipped tight, we headed up the icy hill to the top of Battery Kemble Park.

The “battery” in the park’s name refers to the twin parrot rifles that once aimed down at Chain Bridge, Aqueduct Bridge and rebellious Virginia during the Civil War. The park has less ambitious goals today, primarily serving as a dog-walking venue. As far as the birds are concerned, it’s not spectacular habitat — in D.C. Audubon’s four years of covering the park for the CBC, our most unusual sighting was the time we’re pretty sure we saw NBC’s David Gregory walking his dog — but the scrubby brush at the top of the ridge can host big numbers of small birds, and we went after them first.

Sure enough, the ridge was alive with feeding birds. We counted more than 100 American robins either in the trees overhead or scouring the thawing ground for worms. White-throated sparrows, song sparrows and a rare fox sparrow worked the thick grass looking for seeds, harried by bickering Carolina wrens. We reliably see huge numbers of northern cardinals at Battery Kemble, and there were more than a dozen at our first stop. (We counted nearly 50 before the day was out.)

Everyone needs to work together when you’re trying not to miss a single bird, and our little squad was sharp. Yatsuhashi spotted some cedar waxwings perched quietly in a dense tangle, and Murray spied a hulking Cooper’s hawk — likely a female, which are larger than males, enlarged further by ruffling her feathers against the cold — over a distant rooftop.

We picked our way up around the top of the park and headed gingerly back down through the ice and mud toward Maddox Branch, the stream we would follow all the way down to the overlook at Fletcher’s Cove. We left most of the shrub-loving species behind — sparrows and American goldfinch — and headed into the woods.

Well, next to the woods. The ice that covered the trees was rapidly melting, raining big thick drops down onto muddy trails. We hiked instead down 49th Street, and kept our eyes and ears open.

The woods had their own suite of species. We encountered Carolina chickadees and tufted titmice, and managed to pick out a lone hermit thrush as it zipped across the road into a hedge. Woodpecker diversity picked up, too, with downy, hairy and red-bellied woodpeckers and Northern flicker all making an appearance.

Red-bellied woodpeckers are one of the many species whose population trends have been revealed thanks to Christmas Bird Count data. Scientists began noticing that the species’s range was creeping northward from the American Southeast starting in about 1910, picking up speed in the 1950s. The bird is now fairly common throughout New England, and moving still. Warming temperatures that allow the bird to survive and feed further north is the primary reason.

Christmas Bird Count data has been critical to understanding how birds move in response to climate change. Tufted titmice are expanding northward and boat-tailed grackles are moving west, just two of the 314 species whose range Audubon predicts to shift by 2080. More than a third of species that spend their winters in the United States are declining, mainly from loss of habitat, including the Northern bobwhite, American kestrel and D.C.’s official bird, the wood thrush. There are some bright spots: Peregrine falcons and bald eagles have responded to intense conservation efforts and have rebounded from their midcentury nadirs.

As our team crossed MacArthur Boulevard and down through the lovely Potomac Palisades Park, a small flock of ring-billed gulls was a nice pickup, and we finally saw a pair of powerful red-tailed hawks in trees looking over the Potomac, but at this point in a bird count it becomes as much about the birds you haven’t seen as the ones you’ve got. “How have we not seen a northern mockingbird?” we asked ourselves. “Where are the vultures? We’re still missing a pigeon!”

There’s a house on the corner of Nebraska Avenue and Sherier Place NW with an incredible bird-feeder set up, and we paused to enjoy another large burst of woodpeckers, house finches, Carolina chickadees, mourning doves, Northern cardinals and tufted titmice. No new species, but it was good to see so much activity.

As we walked through the pleasant neighborhoods along Nebraska Avenue and Chain Bridge Road back to the entrance of Battery Kemble, we braved another meltwater shower and reconvened in the parking lot to go over our tally. We ended the day with 27 different species, fewer than in previous years but pretty good considering the difficult conditions. We had some high numbers for some species, though, including 190 American robins, 77 white-throated sparrows, 20 red-bellied woodpeckers and 30 mourning doves. Dampened by the weather but buoyed by our contribution to citizen science, we said goodbyes and headed home, to dry off.

The D.C. Christmas Bird Count was one of the earlier ones this counting season, which runs from Dec. 14 through Jan. 5. Check the Audubon website to volunteer for a count near you.

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