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It’s fall migration, and you’re out looking for warblers. They’re not helping. Back in the spring, they were brightly colored and singing to beat the band. Now they’re drab and keeping mum. What do you do? 

Take a tip from Kenn Kaufman: “In fall, we often just walk through the woods listening for chickadees and then track down the warblers that are with them,” says the renowned bird expert and Լ����Ƶ field editor. As many birders have observed, groups of chickadees tend to attract other songbirds. And since warblers often congregate with one another during migratory stopovers, following the sound of chickadees can lead to a smorgasbord of warbler species, Kaufman says: “If a chickadee group has one warbler accompanying it, there are likely to be others, so it’s worthwhile to follow along and make sure you’ve seen every individual.”

There are good reasons for birds passing through an area to join up with those that live there year-round. For one thing, resident birds know where to find food, water, and shelter. But chickadees also provide another valuable service to other birds: They sound a warning when predators are nearby.

It’s likely that alarm calls are similar across chickadee species, Kaufman says, but they’ve been most closely studied in Black-capped Chickadees. Their vocalizations come in two styles. Rapid-fire seet calls warn of a predator in motion, while the namesake chick-a-dee is a sort of battle cry that rallies other birds to mob a predator perched nearby. The more dangerous a chickadee perceives a threat to be, the more dees it tacks onto the end of its call. In , researchers found that chickadees saved their longest calls for smaller predators that can maneuver easily through forests, such as pygmy-owls and Cooper’s Hawks, and showed less concern about larger but less agile species like Great Horned Owls and Red-tailed Hawks.

Evidence suggests that, even though warblers, vireos, and other passers-through don’t make those same sounds, they understand their general meaning. During in Brazil, Colombia, and Costa Rica—countries where no chickadees live—researchers played recordings of chick-a-dee calls to see what local birds would do. Even resident, tropical species that would be totally unfamiliar with chickadees reacted by flying over to the speaker playing the sounds, suggesting that the response is at least partly a matter of instinct. 

Kaufman says he’s seen them group together with the widespread Black-capped Chickadee, the Carolina Chickadee of the Southeast, and the Mexican Chickadee in Arizona’s Chiricahua Mountains. It’s likely that birders can find migrating birds tagging along with all seven of North America’s chickadee species, he says. 

This birding hack becomes especially valuable in open woods. Inconspicuous fall warblers might still be fairly easy to find when they’re concentrated in an urban park, but larger natural areas tend to have patches where birds are few and far between. Homing in on chickadee calls can help you spend less time wandering aimlessly—not that there’s anything wrong with that!—and more time enjoying migrating birds before they’re gone for the winter.

By the time warblers return north in the spring, most chickadee flocks have disbanded to focus on mating, making this trick less effective—and less necessary, anyway, since the travelers are more vocal and visible in their breeding plumage. But during fall migration, listening for chickadees is a great way to engage your senses, immerse yourself in nature, and often find some really good birds. Even if you don’t stumble upon a lifer warbler, at the very least you’ll get to spend some time among feisty, cheerful chickadees, and that’s time well spent.