A Ventriloquist's Voice in the Forest

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The dim, dripping forests of the Pacific Northwest ring with an otherworldly song—a "ventriloquist voice," as writer Lyanda Lynn Haupt describes it—a single chord whirring with harmonics that seems to emanate from nowhere in particular, and yet everywhere at once.

In 1909 ornithologist William Leon Dawson waxed poetic about his favorite Northwest singer: "The thrush mounts the chancel of some fir tree and utters at intervals a single long-drawn note of brooding melancholy and exalted beauty—a voice stranger than the sound of any instrument, a waif echo stranding on the shores of time." Likewise, naturalist Louis Agassiz Fuertes characterized the Varied Thrush's spartan song "...as perfectly the voice of the cool, dark, peaceful solitude which the bird chooses for its home as could be imagined."

Instead of a larynx—the vocal musculature found in mammals, reptiles and amphibians, also known as the "voice box"—birds possess a wishbone-shaped structure called a syrinx. Major differences lie in the structure and location of each organ. Larynges are mostly cartilaginous, manipulated by muscles both inside and outside the organ to vary loudness and pitch; syringes are anchored in bone, similarly wrapped in muscle but further supplemented with air sacs and elastic tissue called "tympanic membranes," which give rise to the trills and warbles so common to birdsong. Whereas the larynx perches at the top of the trachea, or "windpipe", the syrinx sits at its base, just before it forks toward the lungs. It's thought that the position of the syrinx—directly above a junction, with muscles and membranes on either side—allows for the ethereal, simultaneous tones produced by some birds, thrushes in particular.

Varied Thrush live year-round in Oregon, preferring deep forest and higher elevations throughout spring and summer. In the winter, look for these plump, pumpkin-striped birds in wooded areas along the Oregon coast, where they gorge themselves on late-clinging fruit and insects among the leaf litter.