Male sparrows are less intimidated by the songs of aging rivals

Few singers reach their sunset years with the same voice they had in younger days. Songbirds are no different. New 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 by their voice. But this is the first time the phenomenon has been demonstrated in wild animals.