Those singing on the forest floor use tonal sounds and lower frequencies than those singing in the canopy.
In the open, sound travels best a few feet or so above the vegetation, so birds sing from perches to reduce interference. “Vocal learning, on the other hand, involves the ability to hear a sound and then, by using muscles of your larynx or syrinx, to actually repeat that sound yourself,” explains Jarvis, “whether it be a sound learned in speech or the note of a birdsong.”Ĭlose to half the birds on the planet are songbirds, some four thousand species, with songs ranging from the mumbled melancholy chortle of the bluebird to the forty-note aria of the cowbird, the long, byzantine song of the sedge warbler, the flutelike tune of the hermit thrush, and the amazing seamless duets of male and female plain-tailed wren.īirds know where to sing and when.
“They are born knowing how to scream or cry or hoot.” These utterances are innate or imprinted, like a sheep’s baa. “Nearly all animals that communicate vocally do it by instinct,” says Jarvis, who studies vocal learning at Duke University. This light popular science read doesn't present much new framing or insight Ackerman seeks out current research to discover a few surprises, such as a possible role for olfactory cues in navigation, but doesn't point to or create any big conceptual shifts.
Though Ackerman's focus is mainly ethological, she also speculates on the possible relationships between complex task completion and evolutionary fitness. But her most interesting bits of trivia play to that urge: undergraduates who fail at mental simulations at which some birds succeed, bowerbirds trained to distinguish good human art from bad, Thomas Jefferson's mockingbird singing "popular songs of the day," and pigeons learning to open automatic cafeteria doors. Ackerman interviews specialists without overindulging in research travelogue, keeping centered on her feathered subjects rather than on the human interactions, and urges against anthropomorphizing bird behavior, correlating specific behaviors to generalized intelligence, or benchmarking the value of avian mental skills to that of humans. She explores birds' capacities for tool use, socialization, navigation, mimicry, discrimination, and possibly even theory of mind. Popular science writer Ackerman (Ah-Choo!: The Uncommon Life of Your Common Cold) puts paid to the notion of being birdbrained with this survey of the observational and experimental evidence for impressive bird cognition.
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