He hails from Ohio.
Borror Laboratory of Bioacoustics, Department of Evolution, Ecology, and Organismal Biology, Ohio State University, Columbus, Ohio. All rights reserved.
To override the noise of your computer, turn the volume up high on your speakers and you'll hear in the background a mixed choir of spring-morning songsters, including blackbirds, warblers, sparrows, a raven, and a distant meadowlark replying with his own musical no-trespassing sign.
. . . and the note differs considerably
Meriwether Lewis, wrote Jefferson in a letter to Dr. Benjamin Rush in February of 1803, "is not regularly educated, but he possesses a great mass of accurate observation on all the subjects of nature which present themselves here, & will therefore readily select those only in his new route which shall be new."1 That Lewis could make comparisons of those three details—the tail feathers, the beaks, and the "note"—is ample evidence of the accuracy of the President's assessment of his qualifications.
How do they do it?
Songbirds hatch with built-in, functional calls. They use them to communicate simple signals such as alarms, which may be recognized by any other species within earshot. Contact calls serve between mates to indicate relative locations. Bird songs, which are more complex, are used in courtship, and at the same time serve as audible fences to keep rivals out of the suitor's territory. Songs are learned by chicks over periods of weeks or months. Studies have suggested that every bird hatches with a neurological template implanted in its brain, which enables it to sort out the sounds in its environment, and learn from successful, older neighbor males the songs it needs to know.
The song of the western meadowlark Lewis studied differed considerably from that of the "old field" lark back home in Virginia. But in general, any songbird may have a repertoire of up to ten different "song types," and there may be infinite varieties of local dialects among members of the same species. Therefore, the two meadowlark songs on these pages may only remotely sound like those of the same species in your neighborhood.
Birds do not have larynxes and vocal cords as humans do, but produce the notes of their songs by blowing air over elastic membranes in an organ called a syrinx, which is between the trachea, or windpipe, and the two bronchial tubes connected to the lungs. A bird utilizes nearly one hundred percent of its breath to produce sounds, compared with only two percent used in human speech.
Birds with complicated songs have from five to nine pairs of syringeal muscles with which they can change the tension in those membranes, like violin strings, to produce various pitches. In contrast, the monotonous pigeon has only one pair of syringeal muscles. The size of the tracheal resonator, combined with the size and capacity of the lungs, determines the loudness of a species' song.2 Meadowlarks, both eastern and western, obviously are well endowed on both counts.
A songbird's musical career is not very long. Although the oldest known American robin lived a venerable thirteen years and eleven months, the median life expectancy of songbirds in general is between one and two years.3 The maximum life-span of the meadowlark is not known, but on average, both the eastern and western species are at greater-than-average risk of early death because they nest on open ground, where broods may unintentionally be destroyed by farm machinery. Today we are short on "old fields."
1. Donald Jackson, ed., Letters of the Lewis and Clark Expedition, with Related Documents, 1783-1854 (2nd ed., Urbana: University of Illinois Press, 1978), 18-19.
2. John K. Terres, ed., The Audubon Society Encyclopedia of North American Birds (New York: Wings Books, 1991), "Voice and sound-making: An illustration of a syrinx" will be found on the Web at British Garden Birds, http://www.garden-birds.co.uk/information/birdsong.htm
3. Ehrlich and others, The Birder's Handbook, 643-647.