There’s stealing the show with your own songs, and then there’s taking it to another level and stealing the songs of others. In the human world, mimicry may be construed as flattery or copyright infringement, but in the bird world, it is intrinsically linked to survival both of the individual and the species.
In the world of avian mimicry, one bird reigns supreme. In 2007, celebrated naturalist David Attenborough and his team managed to film one of the world’s most applauded mimics, the Australian superb lyrebird. Famous for its uncanny ability to imitate everything from camera shutters to chainsaws — not to mention dozens of other bird species — it’s often crowned the king of mimics. But you don’t need to travel to Australasia to find world-class impersonators; the Americas are home to their own talented vocalists, particularly in the family Mimidae, better known as the Mimids.
There are around 30 species in this group that includes tremblers, mockingbirds, thrashers, and catbirds, all songbirds best known for their complex repertoires and astonishing ability to copy the songs of other species. Mimids are sometimes referred to as “mimic thrushes”, despite not being part of the Turdidae, the true thrush family, and this misnomer likely stems from their appearance and behavior: they are often upright and hop along the forest floor, having long, strong legs for passerines, and while their plumage can include blacks and blues, more often than not they will be more dully-hued in browns, buffs and greys, exhibited in a thrush-like pattern with streaks and spots. Mimids by and large have red, yellow, or white irises and often sport long bills that curve downwards.
Found across the dry expanses of western North America, the sage thrasher is a modestly dressed bird but in possession of an outsized voice. Its plumage is subdued with pale streaks and sandy tones, but when it sings, usually around dawn during breeding season, it unleashes a torrent of musical phrases, stringing together whistles, chirps, and borrowed calls from other birds with extended performances that can last up to 20 minutes. Also known as the mountain mockingbird, it imitates birds that share its habitat, including Western Meadowlark, Brewer’s Sparrow, and Horned Lark.
Mockingbirds are infamous for borrowing the calls of dozens of other species — hence the name. Northern mockingbirds not only learn their songs in the nest, but they add to them over the rest of their lives and can learn as many as 200 individual species’ songs, along with the sound of slamming doors, creaking gates, dogs barking, doorbells, phones, carnival music, construction noises, cats, crickets and the occasional police siren.
Named for their cat-like calls, their well-developed voice box (known as the syrinx in birds) of this catbird species is able to not only mimic other birds but also expand its repertoire to tree frogs and mechanical noises; their alarm call sounds like a subdued male mallard.
Their songs are easily distinguished from other mimids, however, by a rule that is a surefire way of narrowing down who you are listening to: mockingbirds repeat their phrases three times, thrashers twice, but catbirds, usually just the once. They are also less conspicuous than other mimids preferring to hide in foliage rather than prominently perched in full view.
Often misunderstood as novelty, all of these vocal impersonations likely serve two primary functions: mate attraction and territory defense. A large, varied repertoire is thought to signal cognitive fitness to potential mates, while mimicking the calls of other species could confuse competitors and even scare off predators. Many mimids — including blue jays, technically a corvid — frequently mimic hawks, the red-shouldered hawk among them. But why imitate a raptor? By mimicking the red-shouldered hawk’s scream, the theory goes that these birds aim to trick others into believing a threat is near, clearing the area, thus giving the mimic bird access to more food or space. Another theory leans toward acoustic variety — the hawk’s piercing cry is simply one more dramatic sound to spice up the performance.
