Plumbeous Vireo, Vireo plumbeus

Plumbeous Vireo, 4/21/09, Agua Caliente Park, Tucson, AZ
The bird photographed above and below was a difficult identification between Cassin's and Plumbeous Vireo. Plumbeous is the common summer resident "Solitary" Vireo in Southeast Arizona, but Cassin's is a common migrant through the area in Spring. Plumbeous is the most drab of the three species in this group, gray overall, sometimes with a faint yellow wash on the flanks, and with a relatively distinct contrast between throat and auriculars. Cassin's typically has more green on the back and more yellow on the underparts, with weaker throat-auricular contrast, but drab adults can approach Plumbeous in appearance. Two California birders very experienced with Cassin's leaned strongly toward identifying this bird as Plumbeous. (The third member of the Solitary Vireo group, the Blue-headed Vireo of eastern North America, is the brightest and most colorful of the three species.)

Plumbeous Vireo (?), 4/21/09, Agua Caliente Park, Tucson, AZ