I was listening to a Northern mockingbird run through his repertoire last week. Mockingbirds are by far the most accomplished voice mimics of other birds in our area. I have identified dozens of calls and songs of other species coming from a single mocker in just a few minutes. But Northern mockingbirds are not the only birds that copy other species’ sounds.
Their close cousins, the brown thrasher and gray catbird are both known for their mimicry. Thrashers seem to be better at it than catbirds; the catbirds often have a limited song cache to pull from. Still, some individuals are better than others at it.
If you pay attention to bird sounds you have probably heard blue jays imitating red-shouldered hawks and red-tailed hawks. They are really quite expert at copying both of those species.
At close range I can tell the difference pretty easily. The sound of the jay imitating the red-shouldered hawk is spot on, but lacks the volume and forcefulness of the raucous raptor, but at a distance it can be more difficult to tell the difference. Red-tailed hawk calls sound like a scream given by a bird with laryngitis. The blue jay’s version is again spot on.
Starlings give a wide array of varying calls, some very good imitations of local birds. They are members of the myna family after all. You have to listen closely to pick them out among the squeaks and squeals that dominate the starling’s vocabulary however.
Over the years I have learned that another more unlikely bird can be a very good mimic. White-eyed vireos have a characteristic song but some individuals incorporate some short calls from other species into it. I have heard white-eyed vireos use wood thrush, Carolina chickadee, house wren, Carolina wren, and American robin calls and phrases.
Singing slight variations of a typical song could be a strategy to put a singing male bird out there as more talented and desirable to a prospective mate. Incorporating other species’ calls into one’s own may also be a territorial strategy to drive off other species.
That brings us back to the mockingbird. They are among the most aggressive and territorial of our local birds. They drive other birds away from feeders in winter, so springtime singing may be meant to have the same effect on breeding birds around the mocker’s chosen territory.
Taylor Piephoff is a naturalist with an interest in the birds and wildlife of the southern Piedmont: PiephoffT@aol.com.