Think of the Red-headed Woodpecker as the ‘Red-hooded’ Woodpecker. This will help you remember the difference between the Red-headed and the Red-bellied Woodpecker, which some people identify as Red-headed because it has a red crest. Adults are strikingly tri-colored, with a black back and tail and a red head and neck. Their underparts are mainly white and the wings are black. 
Cornell says their pattern is so bold that they have been called a ‘flying checker board’.  Adult males and females are identical in plumage while juveniles have very similar markings, but have an all grey head. 
The Red-headed Woodpecker’s population is in decline and its status in Canada is listed as threatened. We do have them here in Peachtree Park, but no confirmation on whether they nest here.
These birds fly to catch insects in the air or on the ground, forage on trees or gather and store nuts. They are omnivorous, eating insects, seeds, fruits, berries, nuts, and occasionally even the eggs of other birds.  They, like other woodpeckers, nest in the cavities of dead trees (snags).
References and Additional Information
 Wikipedia: Red-headed Woodpecker
 The Sibley Guide to Birds, second edition – David Allen Sibley
 Cornell – All About Birds: Red-headed Woodpecker
 Cornell – All About Birds: Red-headed Woodpecker – sound
 The Breeding Bird Atlas of Georgia – UGA Press: Schneider, Beaton, Keyes and Klaus, Eds.