石雀的歌声里

A male songbird’s tune advertises his status and availability to choosy females. But rock sparrows offer a notable exception: their crooning can also reveal when the male has been jilted.

Researchers studied the songs of male rock sparrows in the French Alps. These sparrows have a simple song—one element, repeated several times, as you can hear in this young male.

When the researchers compared a male's song to his success in siring chicks, they found subtle surprises. Older sparrows—who have slower-paced, higher pitched songs than younger birds—sire the most chicks. This suggests females use other cues, such as physical appearance, in selecting the best mate.

In an added twist, males whose mates have paired off with another bird sing louder than males with faithful females. This is the first known case of an inverse link between bird song volume and a male’s nesting success. The study is in the journal PLoS ONE. [Erwin Nemeth et al, Rock Sparrow Song Reflects Male Age and Reproductive Success]

The male isn’t just singing his sorrows, however. The researchers propose that the male raises his voice in a desperate attempt to call back his partner—the rock sparrow version of the late-night drink-and-dial.

—Daisy Yuhas