I’m on a Zoom call with a team of researchers from the Cornell Lab of Ornithology, their gridded video feeds a sort of Hollywood Squares of bird nerds, and we’re discussing the decline and fall of North America’s bird population — a staggering loss of 3 billion breeding adults, or nearly 30 percent of the population, in just a half century — when all of a sudden Gus Axelson picks up his binoculars and peers out the window.

“Gus,” I ask, “are you birding right now?”

Axelson, the Cornell Lab’s editorial director, hastily apologizes, but I tell him to go ahead and bird. I have a job, but birders like Axelson have a calling, and no one can predict when nature will call. “I had white-throated sparrows that have been gone for a couple of days,” Axelson, who leads production of Living Bird, the lab’s quarterly magazine, explains when he puts down the binoculars. “They just popped back up.”

By itself, this information is meaningless to me. What the heck is a white-throated sparrow? But it turns out these creatures are also part of the great bird decline, a fact Axelson’s colleagues at the Cornell Lab can show in vivid detail. During their summer breeding season in the Northeast, white-throated sparrows have grown scarcer over the past decade. Even abundant species like American crows and American goldfinches have grown rarer.

We know this because of eBird, the crowdsourced database of bird observations managed by the Cornell Lab. eBird is to older bird databases roughly what Wikipedia is to Encyclopaedia Britannica — instead of depending on the observations of a relatively small group of trusted experts, eBird uses the internet to aggregate the observations of the entire birding world.

Unlike Wikipedia, eBird offers little incentive for deliberate sabotage, but if a prankster were to claim she saw ten thousand grackles in her backyard, eBird would automatically flag her submission for review by a local volunteer. The system makes it possible to trace the fine contours of the great bird decline and, ornithologists hope, figure out how to reverse it.

“It’s kind of uncommon to find a birder in 2024 who doesn’t do eBird,” said Ted Floyd, editor of Birding, the magazine of the American Birding Association. “There are probably more eBirders than there are birders who use binoculars.”

Floyd is the world record holder for consecutive days with an eBird submission, having submitted observations every day since Jan. 1, 2007. When we spoke on the phone, he had just finished his lunch break, which he spent by a pond near his home in Lafayette, Colo., counting the green-winged teals, red-tailed hawks and every other species he saw.

All those observations were fed into eBird, where they joined the bird sightings of hundreds of thousands of people from every country on Earth. Below, you can see population trends of the most common bird species in your town or city. In the table, “abundance” refers to the number of individuals you could expect to see if you went birding for one hour over two kilometers.

“When you have people across the world going out and looking for birds and submitting their data online, this is where we really get the power to understand how birds are responding to landscape scale issues like climate change,” Brooke Bateman, the director of climate science at the National Audubon Society, told me.

In the American Southwest, increasing drought and extreme heat have become more commonplace, putting new pressure on desert birds that already live in conditions precariously close to their physiological limits. As a result, birds like the greater roadrunner of “Looney Tunes” fame and the cactus wren, Arizona’s state bird, have grown scarcer.

In the early 20th century, Joseph Grinnell, a titan of American ornithology, made detailed field notes on the bird populations of the Mojave Desert. A few years ago, researchers from University of California at Berkeley returned to Grinnell’s survey sites, only to discover that the bird populations there had been slashed in half.

“Declines were associated with climate change, particularly decreased precipitation,” the researchers wrote, and warned that “declines could accelerate with future climate change, as this region is predicted to become drier and hotter by the end of the century.”

The spread of towns, cities, farms and ranches across the Southwest has also disrupted desert birds’ natural habitat. Human development has played an even larger role in the plight of birds that live and breed among the grasslands of America’s heartland. Between 1970 and 2019, grassland birds suffered population loss of 34 percent, the largest decline of any bird habitat studied in the 2022 State of the Birds report.

More than half of the native grasslands in the United States have been converted to farmland, amounting to hundreds of millions of acres of habitat loss for birds like Bobolinks, whose females nest in the tall grasses of prairies and meadows.

As the grassland habitat has changed, new threats have been introduced, including pesticides like neonicotinoids, which recent studies have shown can be harmful to birds.

As the American landscape has changed, many species have suffered, but some have thrived. Some birds find that towns and cities mimic their natural habitats, or even provide new advantages — peregrine falcons, for instance, can spot prey perched atop tall buildings.

Other birds are generalists: they eat all sorts of food and live in all kinds of places. Blue jays will eat pretty much anything — seeds, nuts, insects, even other birds’ eggs and nestlings — and are so aggressive around birdfeeders that the internet abounds with advice on how to shoo them away.

But most birds cannot simply replicate such successes. A cactus wren that nests, roosts and hides in saguaros can’t learn much from a peregrine falcon or a blue jay. Is it possible to save the birds who can’t adapt to human shaped habitats?

The answer may lie in the success of America’s waterfowl, creatures like ducks, geese and swans that have enjoyed long-term population growth. “There’s been so much money put into waterfowl conservation, and their numbers are going up,” said Kathi Borgmann, the Cornell Lab’s communications manager.

Why all the money for waterfowl conservation? A major reason is hunting. About 1.5 million federal bird hunting licenses, called Duck Stamps, are sold each year, each for $25, with the revenue sent to conservation projects that have protected millions of acres of wetlands.

Hunters kill millions of ducks every year, and still many — though not all — duck populations are growing because their habitats are protected. But the habitats that are conserved are the ones where the game is. Many ornithologists want to know whether birds that aren’t hunted, birds most people don’t notice or care about, can be saved too.

Birders have called on Congress to pass the Recovering America’s Wildlife Act, which would direct $1.4 billion annually to state wildlife agencies and tribes to protect vulnerable animals. The bill was reintroduced last year by Sens. Martin Heinrich (D-N.M.) and Thom Tillis (R-N.C.) but failed to pass. “I am still hopeful, even in this divided Congress, that this issue is something that Republicans and Democrats can find agreement on,” Heinrich said in an emailed statement.

In the meantime, ornithologists recommend planting native plants, using fewer pesticides, and keeping your cats indoors. If you’re a birder yourself, you can contribute to eBird or other data collection efforts like the Christmas Bird Count, Bateman told me. “Those data are integral in our understanding of birds in a changing climate, and where we need to implement conservation actions to help birds in need.”

How is your favorite bird doing?

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American Crow12%

Abundance

Change, 2012-2022

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Data are from breeding season (May 10-July 5).

Clarification: An earlier version of this column incorrectly described what eBird’s “abundance” variable means. It refers to the number of sightings you could expect if you went birding for one hour over two kilometers, not the other way around.