Female Blackpoll Warbler

I may have to come back and edit this post because I'm not at all sure which bird this is. Pam had commented that she had been enjoying the warblers and wrens from the kitchen window so I went out with the camera in the gloom of an overcast early evening to see if I could get lucky again.



This bird looks very familiar but after studying Sibley's for a long time, the best we can come up with is that this might be a female Blackpoll warbler. My sense is that it isn't yellow enough and that cap looks more pronounced than Sibley's drawing.



This second picture doesn't help much.

Update: we now have independent confirmation that this is a female blackpoll warbler.