I thought it was a goldfinch and the color confused me. My American Goldfinches are sporting the normal drab winter colors with a hint of yellow here and there, but this bright guy (whose color I did not saturate) looks like the odd man out. Thanks to Doug Backlund of the Nature Photographers Online Magazine Avian Forum for the identification. Learn more about the pine warbler here: http://www.birds.cornell.edu/AllAboutBirds/BirdGuide/Pine_Warbler_dtl.html