The historic distribution of the Bachman's Warbler cannot be reconstructed. The breeding range may have covered a far greater area than the few locations recorded in the 19th and 20th Centuries. Reportedly, it bred in northeastern Arkansas, southeastern Missouri, southwestern Kentucky, central Alabama, and southeastern South Carolina. It occurred with some regularity on the southern Atlantic and Gulf coastal plains, with inland extensions up the flood plains of major rivers. The confirmed wintering range covered Cuba and the Isle of Pines. Migration was recorded along the Gulf Coast and through the Florida Keys and Bahama Islands.
Bachman's may have bred in the drier parts of bottomland swamps, higher in the floodplain. Dominant trees in this habitat include sweetbay magnolia, swamp tupelo, sweetgum, blackgum, water oak, willow oak, and red maple. One theory is that this warbler needed openings in the forest canopy, which allowed thickets of blackberry, cane, and palmetto to emerge. Other ecologists argue that it used mature bottomland and some upland forests. Winter and migratory habitats may have been open to most forest types general, but lowland forests were probably used the most.
It probably consumed insects and arthropods most often, but fruits, flowers, and other vegetation may have supplemented the diet on the wintering range. Bachman's Warbler probably foraged in understory thickets by probing leaves and bark with its curved bill and plucking insects from plants. The only specific foods that have been identified are caterpillars and spiders.
Over a hundred years ago, just a few observations were made of its breeding biology.
About 2 feet above the ground, the nests were hung from shrubs and were entirely hidden by the shrub's spring growth. Holding 3-5 clean white eggs, the nests were made of cane, Spanish moss, lichen, dried grass, and dead leaves. Apparently, both parents fed the young. The only two fledglings ever observed were killed and collected by an ornithologist.
Few data and observations exist. Bachman's Warbler appears have been an early spring migrant and reached Florida in late February. It also migrated early in the fall, when most observations were made in Florida between July and August. Migration probably occurred at night.