When John J. Audubon first described Bachman's sparrow (Aimophila aestivalis) in 1834 he wrote, "This is decidedly the finest songster of the Sparrow Family with which I am acquainted". What makes the Bachman's sparrow song so extraordinary is its variation in song pattern. Generally, an individual's repertoire consists of over 20 different song patterns (Dunning 1993)¹. Recently, CMI Ecologists at Fort Pickett-MTC, VA, described vocal mimicry as being part of that repertoire. Avian vocal mimicry is recognized when a bird includes sounds from its environment, including song patterns from other bird species, into its song repertoire. The Northern Mockingbird (Mimus polyglottos) and the Brown Thrasher (Toxostoma rufum) are examples of mimics that have formed song repertoires by "borrowing" the song patterns of other species. Here, this Bachman's sparrow can be heard mimicking the call of the Common Yellowthroat (Geothlypis trichas) and the Indigo bunting (Passerina cyanea).

Murray, Rebecca L., Tyler P. Stanton, Verl R. Emrick. 2004. Bachman’s sparrows mimic the vocalizations of the common yellowthroat and indigo bunting. Journal of Field Ornithology 75(1):51-52.

Play the Bachman's Sparrow song
Play the Bachman's mimicking a Common Yellowthroat
Play the Bachman's mimicking an Indigo Bunting

¹Dunning, J. B. 1993. Bachman' Sparrow. In The Birds of North America, No. 38 (A. Poole, P. Stettenheim, and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, DC: The American Ornithologists' Union.