The Kirtland's Warbler is a rare visitor to Canada, known to nest only in Ontario and the United States, and to winter in the Bahamas. The species nests on the ground, in the dense undergrowth of young jack-pine groves. The nesting conditions required by the Kirtland's Warbler appear about 10 years after a forest fire and remain for only a few years, until the new trees shade out the undergrowth.
In order to protect the nesting grounds of this species, federal, state and private agencies in the United States cooperated to establish four reserves in the jack-pine country of central Michigan. There, management through controlled burning aims to ensure successions of young forests and the continued existence of nesting grounds for the remaining population.
Such conservation actions have had some success: suitable habitat doubled between 1987 and 1990, and by 1994 the number of singing males had exceeded 500.
Both sexes are generally 14 to 15 cm (5 to 6 in.) long.