Love is in the air!
Consistently when out in fields, I see Bluebird pairs that appear strongly committed to each other. I wondered, do Bluebirds mate forever? In our region, we see Eastern Bluebirds. Ornithologists found from a long term study of Western Bluebirds that the great majority stay together for life. No such studies exist for Eastern Bluebirds however, field observations suggest that about 95 percent mate for life when both are still alive.
Eastern Bluebird female, left, male, right
Interestingly though, mating for life does not exclude extra pair copulations. Genetic studies of broods show that about twenty percent of nestlings are sired by more than one male.
Pairs softly warble to each other early in the morning, the male brings nesting material to a chosen site, and once she has entered his nesting cavity, she will begin to bring nesting material and he will bring food to her to “seal the deal.” In our north of Boston region, you can see the courtship behavior beginning as early as February and March.
Eastern Bluebirds re-mate with another partner if one dies.
In the photos below, it’s very easy to see the difference between a male and female Bluebird. The female’s blue is a more subdued grayish hue while the male’s blue feathers are brilliantly hued.