This Yellow Warbler caught me off guard recently. He shows patches of gray, green, and off-white, but no actual yellow. Occasionally, it is good to be reminded about individual variation. Some birds are just outside the norm.
Structurally, we can tell this is a Yellow Warbler by the plain face with the beady eye and the hefty bill. There is a just a hint of streaking on the breast, indicating that this is a male.
Northern races of Yellow Warbler tend to be duller than our local nesters, and this individual seems to be molting into his first adult plumage, so he provides two important lessons.
First: Look at every bird. The more birds you actually observe, the more you learn about individual variation.
Second: When you see a bird that is “different,” don’t automatically assume you have something rare. Every bird is unique, and the vast majority do not look exactly like the picture in you field guide.