Monday, April 19, 2010

Eastern Bluebird Eggs

Today, 19 April 2010, we found our first Eastern Bluebird eggs of the season: one nest with two eggs, and a second one with seven.
My bluebird box-building friends tell me they often have best success when they place two houses in close proximity, separating these by at least 1000 feet from the next houses.  J.H., however, has enjoyed success by placing single boxes near telephone wires. 

At an AOU (American Ornithologists' Union) meeting in Seattle I heard about a study that showed male Eastern Bluebirds with access to more than two boxes were able to attract more than one female.  As nesting locations were at a premium, the female bluebirds had better success raising young if they were attached to a wealthy real estate magnate, even if they had to share his attentions with other females.  When a male's territory was plastered with nesting boxes, however, the females began bickering with each other and, consequently, their nesting success dropped.  Apparently there are limits to polygamy, even among wealthy bluebirds!

1 comment:

  1. Very nice shot and discussion. Seven eggs is very unusual for an Eastern Bluebird. Two separate females laying eggs in the same nest?