Ah! He's standing on a "torse," or wreath. Parker's A Glossary of Terms Used in Heraldry defines it as:
"Wreath. ... the wreath, technically speaking, is the twisted band composed of two strips of gold or silver lace and silk by which the crest is joined to the helmet; though some wreaths of the fifteenth century were of four tinctures. It is sometimes, but improperly, called a roll, at others a torse. It was, perhaps, copied by the crusaders from the wreathed turbans of the Saracens."
The torse usually consists of the first metal (argent or or) and color (azure, gules, sable, vert, or purpure) of the shield. In some times and places (e.g., Ireland), the torse is usually argent and gules.
In this case, where only the crest (as opposed to the complete achievement of arms, with shield, helm, torse, mantling, and crest) is being shown, the torse is the thing that let's us identify it unequivocally as a crest.
David
