A medium-sized (5-5 ½ inches) wood warbler, the male Pine Warbler is most easily identified by its olive-green back, yellow breast, and dark wings with conspicuous white wing bars. Female Pine Warblers are similar to males, but are somewhat duller. Many North American wood warblers are pale olive-green, but this species alone possesses this plumage in combination with white wing bars. The Pine Warbler breeds across much of the eastern United States and southern Canada, although its range is highly fragmented in much of the Midwest and interior northeast. In winter, northerly-breeding populations abandon their breeding grounds and spend the winter in the southeastern U.S.Populations breeding in the southeast are non-migratory, and isolated non-migratory populations also occur in the Bahamas and on the island of Hispaniola. Appropriately, Pine Warblers primarily breed in pine forests. Migratory populations move into similar habitats in winter as they utilized the summer before, and tropical populations are highly specific to pine barrens or mountain forests where isolated patches of suitable habitat occur. Pine Warblers primarily eat small invertebrates, including insects and spiders, although this species may eat some plant material, particularly fruits and berries, during the winter. In appropriate habitat, Pine Warblers may be observed foraging for food on pine needles and in bark crevices. Birdwatchers may also listen for this species’ song, a trilled “cheeeeeee. ” Pine Warblers are primarily active during the day, but, like many songbirds, migratory populations migrate at night.