Editor’s Note: There's a lot to look forward to in spring, including the welcomed hullabaloo of birdsong. The sheer volume of songs and calls to learn can often feel overwhelming for birders, but these sounds offer both an opportunity and a challenge. Follow along with our birding-by-ear series to learn how to use vocalizations to better ID birds. To catch up, be sure to check out part 1, part 2, part 3, part 4, and part 5.
In part 6, #TrickyBirdID founder and Atlanta Audubon bird guide Jason Ward covers the fascinating world of mimics. Some of our most common backyard birds are born impersonators, meaning they copy other species' songs to compensate for their own musical inadequacies. Knowing how to pick the culprits out from a lineup of sounds is a major help while birding. Here's Jason with his mimicry wisdom.
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“You hear that? It's an Eastern Phoebe. And a Killdeer. And a Northern Cardinal?”
OK, something’s not right here. What you're listening to isn't a three-headed mutant songbird. It isn't another birder trying to pull a dumb prank. In fact, it's a regular bird—one that's highly accomplished at impersonating others.
Birds are amazing singers: It’s why we enjoy listening to them day in and day out. But sometimes, their songs don’t go far enough to impress the ladies. So, they turn to vocal mimicry and pepper their vocabularies with sounds of other animals and objects. A large repertoire is a clear, ringing endorsement to how strong of a suitor a male is. As mimicry is learned over time, a bird that has a large variety of songs has likely been around a long time. It also doubles as a way to dissuade rivals from entering a male’s territory.
With all these motivations, birds can get really good at imitations (you’ve probably heard of the famed lyrebird from Australia), and they practice their tricks more often than you might think. As if birding by ear wasn’t hard enough, this adds another wrinkle to identifying the voices you hear outside. “It sounds like a Sora, but why would a Sora be singing from a dogwood tree?” If you know which species are capable of mimicry, you might avoid the trap of mistaking it for a more unusual bird.
Most mimicry masters in North America belong to the Mimidae family. This group of charismatic birds likes to inhabit dense shrubs and thickets. Yet they'll occasionally seek higher ground to flex their vocal muscles. Let’s run through a few of the common North American species.
The mockingbird is the most notable of the U.S. mimics. Capable of singing up to 200 different song variations, the species combines its vast collection of tunes with a crystal-clear quality that makes each one sound eerily similar to the real thing. Usually, all it takes to separate a Northern Mockingbird from the species they are imitating is a little patience; they're known to repeat phrases several times before moving onto the next sound. So if you hear an Eastern Phoebe, followed by a Tufted Titmouse, followed by a Carolina Wren, in close succession, chances are a mockingbird is the culprit.
Another member of Mimidae, the Brown Thrasher is known to have 1,000 to 3,000 songs in its repertoire, including many imitations. In spring, it can be seen high up on an exposed perch, belting out a variety of songs in either doublets or triplets. Out West, the Brown Thrasher’s relatives, the California and Sage Thrasher, make up for its absence in thickets and brush. To tell the difference between these three species and the birds they copy, listen for repetition. If the bird echoes a pattern two or three times, you’re listening to a thrasher.
This staple Eastern species is known for its cat-like “mew” call; but it’s usually overlooked in the mimicry department. Its song consists of jumbled, mixed syllables with no pauses, so it can be difficult to pick up on the imitations that are blended in. But if you listen closely, you'll realize that catbirds also talented mimics. One catbird was recorded singing like a Wilson’s Snipe, Green-winged Teal, and even a Pacific chorus frog. Note the quality of the song, however. Catbirds have a raspier tone, and their hurried notes are often interrupted by a “mew.”
These copycat skills aren’t exclusive to Mimidaes, though. European Starlings, for one, are incredibly adept mimics. In the southwestern United States, Phainopeplas have been heard imitating more than 10 different species. American Crows can impersonate Barred Owls. In turn, the Yellow-breasted Chat can echo crows, Green Herons, and several other species. But the most reliable, non-Mimidae mimic is the . . .
I remember standing in Piedmont Park in Atlanta, Georgia—a spot I frequent a lot. I was scanning for birds when suddenly, I heard what sounded like a hoarse Red-tailed Hawk screech. Puzzled, I put my binoculars down to find a Blue Jay about 10 feet in front of me. Shortly after its first attempt, it let out a better but still unconvincing Red-shouldered Hawk call. That was two hawk species just seconds apart!
Blue Jays are known for their raptor imitations: Osprey, American Kestrel, Broad-winged Hawk, Cooper's Hawk, you name it. They can also cover several songbirds. But why do they mimic? To scare competition away from food? To intimidate a potential threat? They seem to do it no matter the season.
The jury of science is still out on this one. But what is certain are the differences between real raptor sounds and those from a cunning Blue Jay. Like the catbird, the quality of the call can help. Although jays come close, the authentic screech of a Red-tailed Hawk can make a birder’s hair stand on end. Red-shouldered Hawks belt their shrill-sounding screams over and over. Jays, on the other hand, will do a shorter, gravelly version.
One way to practice your mimic-detecting smarts or general birding-by-ear skills is by taking notes. One of my birder friends keeps a list of all the species he's heard Northern Mockingbirds mimic over the years (it’s pretty long). The next time you hear a mimic singing loud and proud, try to keep up with the phrases and ID the other birds you hear. Or take a recording, slow it down, and play it on repeat during your commute to work or school. You might learn a lesson or two—in birdsong and the art of BSing.