Driving down the road, you spot what seems an odd-looking bird for one perched on a roadside wire. You stop and get only a one- or two-second view before your presence flushes the bird into the nearby woodlot on private property. While probably obvious to most quiz-takers, the subject is a member of one of the zebra-backed woodpecker species found in two genera in the ABA Area, Dryobates and Melanerpes.  What were the features you noted in that brief view that would allow certain identification? More importantly for me, did you note the unheralded ID feature that quickly enables ruling out the most similar species in the ABA Area?