In the fall, the song is different with a sharp peek or plink. The only time this bird is in Connecticut is during the fall migration to South America. In spring, the Connecticut Warbler heads northwest across the southern Appalachians, up the Mississippi Valley to the north central states and Canada. The nest is always on the ground, cuplike and usually in a mound of moss or beside dry grasses or weeds in Poplar woods. The nest is built of grasses and bark strips and lined with plant fibers.
Incubation period is unknown.
Another name for the Connecticut Warbler is Swamp Warbler.