Sweet Tweet By Me: Utilizing Warblers' Undertail Covert Patterns For ID

Here's my latest tweet via Twitter relating to the above title/subject:

Spring Fever Cure: Helpful, Sometimes Diagnostic Wood-Warbler Feature = Undertail Patterns/Undertail Coverts: see pgs. 104-106 in “Warblers” (Dunn & Garrett, 1997).

(CLICK ON THE nearby illustration of the bird to see a closer view of its "undertail covert region." More specific, undertail marks on the bottom (ventral) side of the tail feathers (rectrices) are a diagnostic field mark in some species of New World wood-warblers (e.g., Magnolia Warbler, shown here, with abrupt demarcation/border of white-black)

LASTLY:

PLEASE note you can follow me on Twitter at:
@edelstein1
(but who has the time or the interest? I'd rather watch birds than tweets, correct!? So I'm off to bird and find the latest returning neotropical migrants to our Marin Co. area.)