Cassin's Vireos and White-throated Sparrow in Birchim Canyon

Observers: Tom & Jo Heindel
Remote Name:
Date: 05/07/03
Time: 03:19:52 PM


On 6 May we had at least 10 Cassin's Vireos, many singing, in Birchim Canyon. All but two were very dull individuals exhibiting almost no yellow below but all showing a greenish back contrasting with the gray head. The dullest of Cassin's Vireos are often identified as Plumbeous Vireos because most field guides show Cassin's with obvious yellow along the flanks. In reality many Cassin's show very little to no yellow leading the unwary into a misidentification. Extreme care must be given to identifying grayish vireos. In separating a dull Cassin's from a Plumbeous the back must be seen well in different lighting to determine if the back is gray (Plumbeous) or is greenish or has a greenish wash (Cassin's). Reports of Plumbeous Vireo prior to early May are probably misidentifications of dull Cassin's Vireos. We also had 8 species of warblers: Orange-crowned, Nashville, Yellow, "Audubon's" Yellow-rumped, Black-throated Gray, Townsend's, Wilson's, and Yellow-breasted Chat. The best bird was a White-throated Sparrow what was the white-striped variety.