Female and male wrens sing as one
Source: National Institute on Deafness & Other Communication Disorders
You've heard of married couples who finish each other's sentences, but did you know that this can happen in nature too? The male and female plain-tailed wren, a species of bird found in the Andes of southern Colombia, Ecuador, and northern Peru, complete each other's songs when they couple up, taking turns producing notes to create a cooperative duet that sounds like the song of a single bird. Researchers have discovered that, in order to keep the melody in sync, wrens learn the entire duet, not just their individual contribution. This enables each bird to quickly react to the other, while adjusting timing and pitch. Research suggests that the female wrens lead the cooperative singing to test their male partner's suitability as a mate.