Painted Buntings breed in semi-open habitats with scattered shrubs or trees. Birds from the south-central U.S. breeding population use abandoned farms, strips of woodland between overgrown fields, brushy roadsides or streamsides, and patches of grasses, weeds, and wildflowers. Individuals of the coastal Southeast population breed in scrub communities, wooded back dunes, palmetto thickets, edges of maritime hammocks, hedges, yards, fallow fields, and old citrus groves. The two breeding populations also have separate wintering grounds, though both gravitate toward high grass, shrubby overgrown pasture, and thickets. Eastern breeders winter in shrubby or grassy habitats in Florida and the northern Caribbean. Birds from the south-central U.S. winter in similar habitats in southern Mexico and Central America.
Painted Buntings eat seeds for most of the year, switching to mostly insects in the breeding season. They forage on the ground for seeds of bristle grass, pigweed, wood sorrel, spurge, panic grass, St. John’s wort, sedge, dock, pine, rose, wheat, or fig. They may fly up to grab a plant stem and drag it to the ground, holding it in place with one foot while eating the seeds. During the breeding season they catch grasshoppers, weevils and other beetles, caterpillars, bugs, spiders, snails, wasps, and flies. In addition to ground foraging, in the breeding season they also forage in marshes and in trees, sometimes over 30 feet off the ground. The buntings may pull invertebrates from spiderwebs, or even dive straight through a web to steal a spider’s prey.
Both members of a pair search through dense foliage for nest sites. They usually choose a spot 3–6 feet off the ground—sometimes as high as 50 feet when there is no low vegetation—with nearby perches and open feeding grounds. Common nest plants include Spanish moss, mulberry, mesquite, elm, Osage-orange, greenbrier, oak, myrtle, and pine. In as little as 2 days, the female builds a well-constructed nest that is firmly attached to a supporting plant. Forming an inner cup 2 inches wide and 1.5 inches deep, she weaves together some combination of weed stems, leaf skeletons, bark strips, twigs, rootlets, grasses, and sometimes tissue paper or rag scraps. She binds the materials with cobwebs and sometimes lines the nest with horsehair.