Blue Yellow back Warbler

This small warbler is often hard to see as it forages in dense foliage of the treetops. However, it is easy to hear; the male seems to repeat his buzzy trickle-up song constantly from early spring through mid-summer at least. Northern Parulas hide their nests inside hanging Spanish moss in the South, or in the similar Usnea lichens in the North, where they are impossible to spot except by the actions of the parent birds.