Great Spotted Woodpecker (Dendrocopus maior)

ho dryops or dryokoláptês, druêkoláptes, or drykoláptes [Latin: picus, German: Specht].
Since Aristophanes only gives the generic term dryops (= woodpecker), I suggest he probably had in mind the woodpecker most common in Greece and elsewhere in Europe, the Great Spotted Woodpecker [German: Buntspecht].

Behaviour:

Ancient Associations:

The wooodpecker was best known for his ability to open a nest that a human had blocked with the help of a certain plant he knows (e.g., Plin. 10.20; 25.5). Boiled, it was supposed to provide relief to people afflicted by magic spells (Cyranides 3a), cf. Thompson 93.

B. Bruun/ H. Delin/L. Svenson, Der Kosmos Vogelführer: Die Vögel Deutschlands und Europas, 10th ed. Stuttgart: Franck-Kosmos, 1993, p. 188.
S. Cramp et al., The Birds of the western Palearctic, vol. iv (2nd. ed., Oxford 1989), .
John Pollard, Birds in Greek Life and Myth, London 1977, 47-48.
D'Arcy W. Thompson, A Glossary of Greek Birds, London 1936 (repr. Hildesheim, 1966), pp. 92-93.