These are beautiful birds that nest on my farm every summer. They are one of only two species of Warblers that are “cavity nesters” in the united states. Cavity nesters nest in holes in trees. Usually holes that have been made by woodpeckers in previous years. They will use “bird houses” similar to Bluebirds. The other cavity nesting warbler is Lucy’s Warbler, but they are only found in the Southwest area of the united states.