The same singing that marks a male as 'the guy to beat' at age two signals that he's 'obsolete' by age 10
Date: January 17, 2020
Source: Duke University
Few singers reach their sunset years with the same voice they had in younger days. Singing sparrows are no different. Duke University-led research reveals that elderly swamp sparrows don't sound quite like they used to -- nor do they strike the same fear in other males who may be listening in.
Humans are remarkably good at guessing a person's age just by hearing their voice. But this is the first time the phenomenon has been demonstrated in wild animals, said Duke biology professor and study co-author Steve Nowicki.
The findings were published on January 7 in the journal Behavioral Ecology.
During the early spring, a male swamp sparrow stakes out a breeding territory and threatens any male who dares to trespass on his turf. If a potential rival enters another male's territory and starts to sing, the resident male says "Get out!" by singing back with a rapid weet-weet-weet and flying toward the intruder. Eventually, if all else fails, he attacks.
Previous research by this team showed that male swamp sparrows reach their peak as vocalists at age two, and start to decline after that, singing less frequently and less consistently as they get older.