Warbler ID: Yellow-rumped Warbler

If you are going to be birding this fall, it's time to get very well acquainted with this character. The Yellow-Rumped Warbler is by far the most numerous warbler in the Mid-Atlantic by mid-October. While most other warblers are leaving the country, the hardy Yellow-rump is showing up in huge numbers here. In fact, October is the month when you are forced to sort through the gangs of Yellow-rumps in search of another warbler that may be tucked in with them.

Since warblers are my absolute favorite type of bird, I thought I might give a few tips on identification, beginning with the Yellow-rumped. First of all, this species is well-named: it's most obvious plumage characteristic in the fall is its bright yellow rump, visible while perched or flying. While there are other warblers that have yellowish rump areas, none are as bright and in as sharp of a contrast to the surrounding feathers as in Yellow-rumped. Besides that bright spot of yellow, the Yellow-rumped is a rather drab warbler in fall. Brownish overall, with streaking on the sides and flanks.

Another extremely useful field mark that is easily overlooked are the small white crescents above and below the eye. While not a full eye ring, these marks are nearly always apparent, and with a decent look at the face of a yellow-rump (seeing the white throat contrasting with the brown ear patch), that's about all you need to identify this species. (Side note: if you want to learn warbler identification, learn the faces. You can identify 90% of warblers with just a good view of the head).

If you're new to warblers, it make take some time to recognize that the Yellow-rumped is a large warbler, that moves fairly slowly, though it often flies out from a tree to catch an insect, only to swoop back to that same tree. They are active, but not particularly fast movers. And compared to many other warblers, they actually seem like they could use a few days at the gym. Perhaps their size makes them more suited to handling the colder temperatures of the Northeast in fall and even winter.

Many times, Yellow-rumped Warblers can easily be identified without even seeing the bird, however! This bird has a distinctive hard "chek" note that it gives when in flight (listen to it here). Knowing this note is really helpful when trying to sort through a group of warblers to find something different.

People who seek to find counterfeit dollar bills do it by being extremely familiar with the real thing. If you become really familiar with the Yellow-rumped Warbler, it will make it 10X easier to find other species in the mixed species flocks of fall.