Seen this afternoon in Chapel Hill, NC. I was actually out warbler hunting and saw this bird low, where I was looking down on it from about 20 feet away. What caught my eye was the very bright yellow wing-bar on a medium gray body, so my first impression was Golden-Winged Warbler. It had been raining, so the lens cap was on my camera and I had to scramble to get photos. By then the bird had gone up into a tree and I only got a few shots before it disappeared. It seems the only other bird it could be is a Chestnut-sided, but I'm just not seeing that in the photos. Opinions would be welcomed. Thanks!