Every year around Christmas time, tens of thousands of volunteer birdwatchers gather in familiar locations across the Western Hemisphere for a tradition that dates back more than a century. On select days between December 14 and January 5, volunteers with the National Audubon Society’s Christmas Bird Count take a census of every bird they see as they walk specific routes, or even observe bird feeders, inside a designated 15-mile circle.
“The reason it’s been so successful is that it’s become a holiday tradition for so many people who do it every year,” says Geoffrey LeBaron, Christmas Bird Count director for the National Audubon Society.
The data provided by volunteers also supports some serious science. And in recent years, the Christmas Bird Count has uncovered a troubling trend. Even as the number of volunteer bird counters hits record levels, fewer birds are being counted.
The count’s long standing history also lets researchers track how birds’ ranges have shifted as winters get warmer. Some scientists are even using the observations to try and predict what will happen to certain bird species under climate change in the future.
The First Christmas Bird Count
Through the 19th century, many families in North America celebrated the tradition of the Christmas “side hunt.” On Christmas Day, extended friends and family members would team up and head out into the woods in groups. They’d shoot what they could, then return and show off their bounty. Whoever had the biggest haul won.
In those days, the supply of wildlife seemed limitless. But by the turn of the 20th century, it had become clear to passionate birders that excessive hunting was taking a toll on wild populations. Roughly five million wild birds were being killed each year, many simply for their plumes. Conservationists were pouring considerable effort into trying to stop the killing.
And that’s how ornithologist Frank Chapman, an officer in the fledgling Audubon Society, came to propose the Christmas Bird Count. He hoped people would get out to enjoy seeing birds instead of shooting them.
That first Christmas, 27 birders joined in the new tradition across North America, from Monterrey to Toronto. Together they managed to count some 18,500 birds from 90 different species.
Instead of simply counting birds, the birders also counted the amount of effort they expended trying to find them, tracking the hours spent and distance traveled. According to LeBaron, this was Chapman’s key insight, and across generations, it’s proved pivotal to making the count valuable for research. Having those numbers lets scientists calculate not just the birds observed, but how much work it took to find them.
Long Running Citizen Science Project
Today, 121 years after Chapman’s first event, this tradition has become one of the largest and longest-running citizen science projects. Some 80,000 people take part in the Christmas Bird Count every year. Large numbers of volunteers now join in from places like Columbia and Ecuador, expanding this annual census of birds farther into South America.
However, as the birding event has become more popular than ever, the birds keep getting harder to find. According to LeBaron, 2019’s count broke the record for most volunteers in Christmas Bird Count history. Yet all those people managed to count just 42 million birds. That’s one-quarter to one-half of the numbers counted regularly during Christmas Bird Counts just a couple decades ago. In some years past, the census would tally over 200 million animals.
LeBaron has seen this trend in action himself. Since he was a graduate student in the 1970s, he’s returned to the same place in Rhode Island for the Christmas Bird Count. One year, his group set a record for the most great cormorants seen in a day when they spotted a whopping 3,700 of the dark-colored seabirds. But at the same spot last year, his group counted just 97 cormorants.
“It tells us something is going on for a species like that,” LeBaron says.
Three Billion Birds
It’s not just cormorants. Recent research using the Christmas Bird Count, as well as other sources, has shown that bird populations are plummeting in North America. In 2019, a study published by scientists at the Cornell Lab of Ornithology found that some three billion birds had vanished since 1970. It’s not just one species dying off, either. These researchers found declines in virtually all groups of birds across the U.S. and Canada. Many of the vanished birds come from common species. For example, one-quarter of all blue jays have disappeared and roughly half of Baltimore orioles.
Writing in The New York Times, two of the study authors called it “a staggering loss that suggests the very fabric of North America’s ecosystem is unraveling.”
Their results depend on citizen scientists’ observations, as well as long standing data on migratory species collected by weather radar stations.
The threats include land use, pesticides and pollution. Other research has shown that climate change has pushed some species to change their migration patterns and historical range.
Whatever the cause for the decline, this trend makes the Christmas Bird Count more important than ever. The Audubon now gets dozens of requests each week for its data. And as researchers struggle to understand which species are hit hardest and how to help them, they’ll need eyes on the ground.
“With the Christmas Bird Count, we can say this species or this group of birds are declining,” says Geoffrey LeBaron, Christmas Bird Count director for the National Audubon Society. “Then, we can look at the potential reasons it is declining and find ways to address it with conservation efforts.”
COVID Changes the Census
Despite the growing need, LeBaron says he expects and understands that many participants won’t be able to take part this year because of COVID. Not everyone can safely reach their normal site. Plus, some states’ rules might make the Christmas Bird Count impossible or simply impractical for people to participate. Even those who can join in will have to divert from their normal tradition. Often, participants gather for lunch or at the end of the day to report their observations for the counter to tally. That’s a big part of the holiday for many birders. But this year, LeBaron says that they’re telling people not to gather at all. Family groups can still go out and make their observations, but they shouldn’t carpool with people outside their household and results should be reported virtually. The Christmas Bird Count is open to veteran birders and amateurs alike. But with COVID restrictions, it be harder for newbies to pair up with more seasoned volunteers.
Other people may decide to stay home and report observations from bird feeders. LeBaron says they hope people who can do so safely will still find ways to participate. For those who can’t, the Christmas Bird Count will still be there next year. In the past, a number of sites have had to skip a year for one reason or another. And that’s the beauty of such an old data set.
“When you’re looking at a century-long database, one season is hardly even a blip,” LeBaron says.