Singin in the City
New research shows that human-altered environments might change the communication signals of a wild bird species
SPOTTING a prospective date at a crowded and noisy party, a guy—at the very least—needs to get noticed. A similar challenge seems to confront songbirds that live in cities and suburbs. To stake out territories and attract mates, a male bird’s song must be heard, both by females and rival males, above all the urban din.
New research suggests that at least one songbird, Europe’s great tit, has evolved a strategy to cope with this problem. In the Dutch city of Leiden, Leiden University biologists Hans Slabbekoorn and Margriet Peet studied the songs of 32 male great tits that lived in various parts of the city. They discovered that the birds’ songs varied markedly from one location to another. Males whose territories were located near busy roads or in other noisy spots pitched their songs at higher frequencies than did males in quieter neighborhoods. The finding makes sense, note the researchers, because most urban racket—from cars, trucks and airplanes to lawn mowers and leaf blowers—occurs at lower frequencies.
Thanks to its ability to adapt to urban noise, the great tit (a common European species related to North American chickadees) may have a leg up over songbirds whose behavior is less flexible. In the journal Nature, where they published their results, the biologists write: “Our findings show, to our knowledge for the first time, that human-altered environments might change the communication signals of a wild bird species.”