A large (6 inches) wood warbler, Kirtland’s Warbler is most easily identified by its slate-gray upperparts, streaked back and flanks, and bright yellow underparts. The similarly-patterned Canada Warbler (Cardellina canadensis) is also gray above and yellow below, but is only streaked on the upper breast and throat. Male and female Kirtland’s Warblers are similar in all seasons. Kirtland’s Warbler is by far the rarest extant wood warbler in North America. This species breeds in a small portion of the Lower Peninsula of Michigan, occurring locally even within that range. Kirtland’s Warbler is rarely seen outside the breeding season, although occasional reports indicate that it migrates south through the eastern United States and spends the winter in the Bahamas. More habitat-specific than most other wood warblers, Kirtland’s Warblers breed exclusively in young Jack Pine (Pinus banksiana) forests in areas with sandy soil. This species’ habit of building its nest on the ground is also unusual for wood warblers. In winter, this species has only ever been recorded in the undergrowth of Bahaman pine forests. Kirtland’s Warblers primarily eat small invertebrates, including insects and spiders, and may also eat fruits and berries in winter. In appropriate habitat, Kirtland’s Warblers may be observed foraging for food on the ground or low in the tree canopy. Birdwatchers may also listen for this species’ song, a warbled series of notes lower in pitch than that of most other wood warblers. Kirtland’s Warblers are primarily active during the day in the breeding season, but this species’ scarcity has complicated studies of its behavior at other times of the year.
