If you see a very small blue-grey bird with a light-colored under belly moving head first down the trunk of a tree, it’s probably a White-breasted Nuthatch.
It’s a stocky bird, with a large head, short tail, powerful bill, and strong feet. The upper parts are pale blue-gray, and the face and under parts are white. It has a black cap and a chestnut lower belly.
The nuthatches are a genus, Sitta, of small passerine birds which derive their English name from the propensity of some species to wedge large insects or seeds into cracks, and then hack at them with their strong bills.  Nuthatch may have morphed from “Nut Hack”.
Seeds form a substantial part of its winter diet, as do acorns and hickory nuts that were stored by the bird in the fall. The nest is in a hole in a tree, and the breeding pair may smear insects around the entrance as a deterrent to squirrels.
White-breasted Nuthatches are full time residents here.
Cornell has this ‘cool fact’ on their site: “If you see a White-breasted Nuthatch making lots of quick trips to and from your feeder – too many for it to be eating them all – it may be storing the seeds for later in the winter, by wedging them into furrows in the bark of nearby trees.” 
Like other nuthatches, this is a noisy species with a range of vocalizations. The male’s mating song is a rapid nasal qui-qui-qui-qui-qui-qui-qui. The contact call between members of a pair, given most frequently in the fall and winter, is a thin squeaky nit, uttered up to 30 times a minute. A more distinctive sound is a shrill kri repeated rapidly with mounting anxiety or excitement kri-kri-kri-kri-kri-kri-kri-kri. 
References and Additional Information
 Wikipedia: White-breasted Nuthatch
 The Sibley Guide to Birds, second edition – David Allen Sibley
 Cornell – All About Birds: White-breasted Nuthatch
 Cornell – All About Birds: White-breasted Nuthatch – sound
 The Breeding Bird Atlas of Georgia – UGA Press: Schneider, Beaton, Keyes and Klaus, Eds.
 Cornell – All About Birds: White-breasted Nuthatch – life history