Black-throated Blue Warbler (Dendroica caerulescens)

Very rare in the Raleigh-Durham-Chapel Hill area in winter, this female Black-throated Blue Warbler is lingering on Duke University's campus this winter.

Female Black-throated Blues look very different from males. They're mostly olive with a short whitish eyebrow and square whitish mark along the edge of the folded wing.

Doing his best sapsucker impersonation...

Along with several other species (Yellow-rumps, Song Sparrow, titmice, etc.), she was drinking from oozing sapsucker wells.