Yes, their nickname is butter butts. Why? Because there is a small patch of yellow on their rumps that is obvious as they flit around in the mid-story of trees (above the ground but below the larger canopy). Go ahead and giggle. We do.
Within the Yellow-rumped Warbler species there are two subspecies: Audubon’s, which occur in western North America and Myrtle, which occur in the east. They used to be separate species but were lumped together as one back in the 1970s. Although they look similar, they have enough plumage variation to be identified as one or the other. But no matter which “outfit” they’re wearing, there is always that distinct yellow patch on the rump.
The subspecies Myrtle is the one typically found in our area. And it’s the only warbler that can be found here in winter, much to the amazement of new birders. A warbler in winter? But how? Although they nest in the northern boreal forest, they come “south” for the winter and what makes our climate acceptable to them is the native shrub northern bayberry (Myrica pensylvanica), which grows in abundance at Presque Isle State Park…