I keep seeing these birds at a local conservation area in MA. I have tried looking up what they are, but I can't figure it out. They were foraging with a flock of Chipping Sparrows. Their yellow "eyebrow" lines are quite distinct and bright. They were very shy so the pictures were taken from fairly far away. Also, it was dark and raining, so the picture quality is not great, but I'm hoping someone can help me ID them.