Although geographical variation clinal, and some races rather poorly defined, one study#R found significant geographical differences in most of the seven morphometric and five plumage-coloration characters analysed (as well as clinal patterns) and identified seven geographical units. Isolated form angustifrons, with distinctively shorter wings and darker (brown) eyes, sometimes proposed as a separate species, but further data required. Race lineatus perhaps doubtfully distinct from albeolus. Named form phasma (from Nuevo León, in NE Mexico) is a synonym of nominate; proposed race martirensis (N Baja California) considered indistinguishable from bairdi. Seven subspecies currently recognized.
Food and feeding
Status and conservation
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