I'm no expert on molt, but it appears these two motley blue birds are in a late summer molt! They may also be juveniles. Any bluebird or molt experts want to weigh in?
These birds were seen the last weekend of August near Herrick Reservoir. I believe the top one is a Western Bluebird as I see a hint of rusty flanks. The bottom one I believe is a Mountain Bluebird due to a thinner all dark bill.
According to BNA online hatch year birds (which these appear to be) go through a partial molt from late summer to late fall involving body (contour) feathers. Also younger birds have looser, fluffier contour feathers which can give them a sort of disheveled look so it's probably a combination of both. But note that the wing feathers look quite crisp and unworn which is typical of young birds.
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