Mystery solved

It's a Carolina Chickadee (poecile carolinensis). Finally got a good look at it the other day.

• Small, short-billed bird.
• Black cap.
• Black bib.
• White cheeks.
• Back unstreaked gray.
• Underparts whitish.

Yep. That's the new visitor. And for the record, I did not Google "White cheeks." Or "Underparts."