It’s tough to be sexy. In rough and tumble neighborhoods, boys compete to defend their turf and win the ladies’ hearts. A bird bent on starting a family and maintaining prime real estate needs to fight for that right, and it seems experience counts in this arena. It’s not those young whippersnappers who tend to goad on the rabblerousing—it’s the older gents who have been around the block. But hoary males don’t start feathery brawls to maintain their status. Instead, they incite their competitors with aggressive sing-a-longs of the most popular sparrow hits.
Song complexity and repertoire are known to impress the ladies in a variety of bird species, including starlings, great tits, and warblers. How males chose to exercise their cache, especially with regard to shared songs, is less clear. Researchers at the University of Western Ontario and the University of Windsor examined a population of song sparrows in order to answer this question. They followed males with song repertoires of five to 12 tunes, and the birds’ range varied in the degree to which their tunes overlapped or shared certain song elements. Using a 16-channel acoustic location system, they recorded neighborhoods of song sparrows during their dawn choruses. Some males sang only unique songs while others chose to stick mainly with the most common song sparrow hits.
The ornithologists found that older males living in ‘tougher’ neighborhoods more often engaged in provocative shared song sparring bouts, while more conflict-averse sparrows in ‘mild-mannered’ neighborhoods mostly avoided shared songs. Rather than solely a tool for attracting mates, song sharing seems to serve as an attention-seeking behavior amongst males, the researchers say in their paper published in Behavioral Ecology and Sociobiology (subscription required). In other words, belting out shared songs is akin to guys flinging insults back and forth.
For cocky older males, provoking neighbors with familiar songs is probably not just a showy bluff. The researchers think the more mature and confident birds are also more willing and able to risk an actual conflict with their neighbors. Because of their experience, they may also have more familiarity with which songs really push the annoyance buttons of their local competitors. Ultimately, proudly chirping out the familiar shared songs sends a clear signal to other males: back off.
See also: The oldest music, The sound of music, Copy-cat songbirds