The king vulture is one of the most common species of birds represented in the Maya codices. Its glyph is easily distinguishable by the knob on the bird's beak and by the concentric circles that make up the bird's eyes. Sometimes the bird is portrayed as a god with a human body and a bird head. According to Maya mythology, this god often carried messages between humans and the other gods. It may also be used to represent Cozcacuauhtli, the thirteenth day of the month in the Aztec calendar (13 Reed). An ocellated turkey ("Meleagris ocellata") was also considered to be the bird depicted, but the hooked bill and wattle point to the raptor.