Black-figure painting on an Apulian vase, dating to 400-375 B.C., now
in the Nicholson Museum, University of Sydney, Australia. The image
shows two bird-masked personages with the head surmounted by a cockscomb.
In this case, too, it is not clear to which context the scene could
be referred. It is possible that it could be associated to the Aristophanes’
comedy The Birds, which went on the stage for the first time in 414
B.C. In this comedy, the author retrieved the traditional motif which
attributed to the birds a mediating function between the human world
and the world of the gods. The birds were indeed regarded as messengers
of the gods, and from their observation omens regarding the future could
be obtained.
[Source: http://www.usu.edu/markdamen/ClasDram/chapters/081earlygkcom.htm]