The presence of the evil looking bird on the top of the figure can be explained by the sixth labour of Hercules. A great flock of man-eating predatory birds had descended upon the town of Stymphalos. These were equipped with huge beaks, which were capable of penetrating any armour. The birds were wreaking havoc among the citizens of the town and the task of destroying them fell to Hercules as one of his labours. Using a pair of bronze Krotola or clappers provided by Athena, Hercules made the birds take flight from the trees in which they were perched beside a lake and he was able to kill them at his leisure while all of the time being impervious to their sharp beaks by virtue of the protective qualities of the skin of the Nemean lion. The Stymphalian bird can be seen vainly trying to peck through the skin while the smug countenance of Hercules below denotes his knowledge of his invincibility. A large wooden pipe once adorned the mouth of the figure, which, although it must have been an addition, would have sat well with the general tenor of the carving.
The timber used in the carving, which was visible at the rear where some parts had broken off, looked like yellow pine and, if so, it might denote a North American origin. Here also could be detected a clue to the probable maritime origin of the figure. At some stage in its existence an infestation of Gribble had occurred. This is a marine boring organism,
Heracles killing the Stymphalian birds with his sling. Attic black-figured amphora, ca. 540 BC. Said to be from Vulci.