Birdsong: A Natural History (review)

As the literature of the past few thousand years makes plain, humans from various cultures have maintained a consistent fascination with—and admiration for—the songs of birds. And if poets have sometimes doubted their ability to adequately describe birdsong, it appears that scientists have not been much more successful. Despite having one of the most compelling subjects in the biological world, scientists who study "avian bioacoustics" continue to be troubled by a number of fascinating questions. Some of these questions involve complex evolutionary issues. For example, what is the role of song dialects within bird communities, and what effect does dialect range have on avian genetic fitness and speciation? But many of the questions that remain will strike readers as surprisingly basic. How do birds learn their songs? What is the window of opportunity for that learning? Why do certain individuals customize their expression of a shared song? Is bird singing strictly related to mating and territorial behavior, or is it possible that birds actually sing for the sheer pleasure of it? Why do birds sing? Don Stap's Birdsong: A Natural History reminds us from the outset that we do not yet know the answer to this fascinating question.

Among the pleasures of Birdsong is Stap's effective use of what scientists already know about birdsong to help revivify our admiration for all that chirping and warbling that we hear around our homes. For example, a singing bird uses almost 100 percent of the air passing across its vocal cords to make sound; compare that to the 2 percent or so used by the bird's human neighbor who is singing in the backyard. Or, consider that the average brown thrasher knows more than 2,000 songs. How many of us could say the same? And many bird species have, over millennia, shaped form to function by developing anatomical adaptations that allow for amazingly complex vocalizations. Many birds, for example, have evolved a syrinx with dual bronchial tubes that can be used to produce sounds of completely different frequencies—a neat trick that allows the bird to simultaneously project two sounds that are not harmonically related and thus, in effect, "[sing] a duet with itself."

Though it is not his main subject, Stap is also interested in human conceptions of birdsong, and some of the book's most illuminating moments examine this cultural link between people and birds. "Frogs croak, crickets chirp, wolves howl, and lions roar," he writes, "but birds sing." Do birds communicate in a way that is fundamentally different from other animals, many of which also use vocalizations in complex ways? Or is it the case that the beauty of the warble is in the ear of the beholder? Does our use of the word "song" to describe avian vocalization reflect something fundamental to the sound itself, or do we call bird vocalizations "song" simply as a way of expressing a human aesthetic preference for the sound of the house finch over that of the bullfrog? In discussing this issue of what we might call "acoustic aesthetics," Stap tells fascinating stories of interactions between human and bird "music"—as in the case of Beethoven, Mozart, and Bartók, all of whom incorporated avian melodies into their compositions. (Next time you hear Beethoven's Sixth, listen for cuckoo, nightingale, and quail song!)

Birdsong incorporates and describes biological science, but is not itself a scientific book. Instead, Don Stap's primary technique—one that has been used by many environmental writers and documentarians—is to follow scientists around in the field, describing their work and translating their hypotheses and findings into language that nonspecialist readers can understand and appreciate. To this end Stap has made a sort of literary character of his main figure, renowned avian bioacoustics specialist Don Kroodsma. Kroodsma tramps around the world, hauling piles of field equipment and recording gear, and showing infinite patience as he waits for the right moment to funnel a rare song into the cone of his parabolic microphone.

While a great deal...