Spotting

I am so far from a bird expert -- as astronaut to ant -- but .... Is that yellow on that bird? Is it's olive green due to the foliage? I cannot tell if it has a black spot on it's head? Bachman's Warbler? It's head is big like a phoebes, but the colors seem wrong. Bachman's is extinct, but you never know. Museum image:
http://stockpix.com/image/6293s2.jpg