Sunday, June 12, 2011

Red-winged Blackbird

Among Red-winged Blackbirds, females migrate further south than males. Males, therefore, reappear and begin staking territories in the Minnesota spring before the females arrive.  (Older males migrate shorter distances than first-year males.)  This male was singing on a bush near Circle Lake, Rice Co., Minnesota on 27 April 2011.  What do Red-winged Blackbirds sing?  Some say "Con qer ree."  Others transcribe the song to be "Purple rear!"

Red-winged Blackbirds are one of the most polygamous of birds.  Wealthy males (as measured by quality of their territories) can mate with up to 15 females, who nest in his territory.  The advantage to the male is probably obvious.  Presumably the female who shares a wealthy mate is more successful at fledging her young than if she mated with a "poor" male.  This phenomenon, however, gets more interesting.  DNA studies show that a "wealthy" territory holder has not necessarily fathered all of the young in his territory.  Females, like the males, often copulate with more than one partner, even during a given nesting attempt (Yasukawa and Searcy 1995).  I will leave the explanation to you.

No comments:

Post a Comment