Older Male Sparrows Not Threatened by Younger Males

Older male white-crowned sparrows don't see younger male sparrows as much of a threat. When vying for mates or squabbling over territory, older males don't often bother challenging their younger rivals because they pose little credible competition. Instead, they only pick a fight with other older males that could pose a significant threat to their superiority.

It turns out, the way these birds figure out each others' seniority is based on their songs as well as their plumage. Male white-crowned sparrows use song for multiple purposes including attracting a mate and claiming their territory. Since young male white-crowned sparrows sing differently than older males, song can be used to distinguish age.

After mapping the territories of 16 male white-crowned sparrows, the research team was able to observe how males of different ages responded to songs made by intruders.

They found that older birds did nto react as strongly when they heard the song of a younger bird in their territory.

Photo © Douglas Nelson / Ohio State University