Matt Hafner and I observed this warbler in the fall of 2006 on Assateague Island. Late in migration, most of the warblers were Myrtle with a few Palm and Pine. When the bird flew in I called it a Palm with out lifting my binoculars. It was yellow tinged and pumping its tail like a Palm would. But on closer inspection it looked more like a Myrtle. So, funky plumage and habits, or a hybrid MyrtleXPalm?