The Pine Warbler (Dendroica pinus) is primarily an insectivore, but it's also the only warbler that eats large quantities of seeds, primarily those of pines. During the winter, it often joins mixed flocks of birds. Among our yard birds, we see it at both the sunflower seed and suet feeders. At the sunflower seed feeder, the Pine Warbler is probably foraging for bits of broken sunflower seeds left by other birds whose beaks are more suited to cracking open a sunflower seed. However, Cornell Labs says it can open seeds "by placing them in bark crevices and hammering with bill."
Depending upon whose range map one consults, the Arkansas Ozarks are either within the Pine Warblers year round range or right on the edge of both a year round and migratory range. Some Pine Warblers live year round in the southeastern US. Others breed in the northeast and migrate south during the winter. The key factor is habitat. Pine Warblers require pine trees. Our woods are mixed hardwoods and pines.
I've never seen a Pine Warbler except during the winter, but that proves nothing. If it were still here during the summer, the warbler would be nesting and foraging for insects high in our pine trees and I'd be unlikely to see it.
While the Pine Warbler superficially looks something like an American Goldfinch, there are also many obvious differences: Bill shape, body shape, wingbar placement, etc. The Hilton Pond Center website discusses these difference in detail complete with photographs.