We have the pleasure of finding Palm Warblers in Florida throughout the Winter and Spring. Most of them are the "western" subspecies, and they are rather drab in their winter plumage. But a few are the "eastern" subspecies. These birds sport a fair amount more yellow, even up into the supercilium stripe. These are a special treat for me. I typically see them in the drier habitats, rather than marshes and other wetlands.
Palm Warbler Marl Bed Flats
I'm also told that the western and eastern subspecies actually cross paths during migration. The yellow "eastern" birds typically migrate farther west, while the more drab "western" birds head east into Florida. This accounts for why we see so few "eastern" birds on the east coast of Florida.