Male, Immature Male and Female
Range: Breeds mainly in the Transition Zone from central Saskatchewan, northwestern Manitoba, central Ontario, and Newfoundland south to eastern Nebraska, Illinois, Indiana, northern Ohio, northern New Jersey, and Rhode Island, and south in the Alleghenies to Tennessee and South Carolina; winters from Guatemala to Panama.
Since the days of Wilson, Audubon, and Nuttall there is little doubt that the chestnut-sided warbler has increased in numbers, and within its range it is now one of the commoner of the family. It is trim of form and its colors, though not gaudy, have a quiet elegance all their own. During the fall migration it shows little preference in its hunting grounds, but is found with others of its kin in all sorts of woodland haunts and in deciduous as well as coniferous trees. It frequents open woodland tracts in summer and loves to nest in low thickets of hazel and barberry. In favorable localities in Massachusetts I have frequently found half a dozen nests in a morning's search. The nests are made of shreds of bark and grasses and are put together so loosely and carelessly that, in connection with their situation, they unmistakably betray their ownership.