Hybrid Bluebirds in the Pine Ridge

A hybrid pair of bluebirds is raising young in Dawes County, Nebraska, in the yard of Jim and Hope Minyard, approximately 8 miles south of Crawford. The female of the pair is a Mountain Bluebird (Sialia currucoides). She is basically a dull gray bluebird, with little contrast between upperparts and underparts. There is no rusty or tan on her breast, and no sharp demarcation between the gray breast and the lighter belly. Her rump and the bases of her outer tail feathers are a light, bright blue, while the other tail feathers and the primaries are blackish. When the wing is folded, her longest wing feathers approach, but do not reach, the tip of her tail. The male presents a more complicated picture. Superficially he resembles an Eastern Bluebird (Sialia sialis) because the upper parts are uniformly bright blue, the breast and throat are rusty, and the belly is white. The blue of his upperparts appears a lighter, more cerulean blue than is typical of Eastern Bluebirds, though it is difficult to judge without direct breast comparison. The rusty breast is paler and duller than usual for male Easterns as well. Most peculiarly, there is a small, bright blue bib or necklace on the upper breast, similar in color to the back. When folded, the male’s wing tips reach a little over half way down the tail. In other words, his wings are relatively shorter than those of the female. We believe that the male is a Mountain x Eastern Bluebird hybrid