Juvenile bird plumage is often strikingly different from the plumage of their parents. Additionally, many juvenile birds, at least to me, look very similar with their spotted patterns. I have a difficult time identifying many avian juveniles.
Earlier this month Leonard and I saw a large flock of mountain bluebirds (Sialia currucoides) near the intersection of Modoc County Roads 91 and 85. Mountain bluebirds prefer open country with a mix of grasses, shrubs and trees where they can forage for insects, their primary food. Mountain bluebird hover while searching for prey or forage from perches.
I photographed several “brownish, spotted” birds. Usually I would give up in my attempt to identify the plain brown birds since their markings are so common. However, there is no mistaking the cerulean, adult mountain bluebirds with which they were associating. Identification of the juvenile mountain bluebirds was simplified.
Juvenile mountain bluebirds are spotted dark below, have a distinct white eye ring and are a dull brown-blue on the wings and tail. The beak is black.
The juvenile mountain bluebirds probably were recently fledged from their nests in nearby tree cavities. (Mountain bluebirds also use nest boxes in more urban settings.) Female mountain bluebirds choose male partners on the basis of the location and quality of the nesting cavity offered rather than plumage or singing ability. The female built the nest this juvenile vacated entirely by herself by covering the entire floor of the nest cavity with coarse, dry grasses before hollowing out a cup in the grass.
The reference picture of a mature adult mountain bluebird was taken in November in one of our pastures near Lookout CA (Modoc County). It was snowing.
A previous post (“Mountain Bluebird” on 11-10-2011) gives more information about mountain bluebirds.