Scared of a Younger Rival? Not for Some Male Songbirds

ScienceDaily (Feb. 7, 2012) — When mature male white-crowned sparrows duel to win a mate or a nesting territory, a young bird just doesn't get much respect.

Researchers found that older male white-crowned sparrows don't put much of a fight when they hear a young male singing in their territory -- probably because the older bird doesn't consider the young rival much of a threat.

But a male sparrow will act much more aggressively if it hears a bird of the same age singing in a territory it claims as its own.

"These male sparrows assess an opponent's fighting ability based on age. And for a mature sparrow, a young male is just not going to scare them," said Angelika Poesel, lead author of the study and curator of Ohio State University's Borror Laboratory of Bioacoustics and the tetrapod division.

Read on:  http://www.sciencedaily.com/releases/2012/02/120207202302.htm