"The inclined benches each had a raised surface running transversely through their central axes, inscribed with hieroglyphic text. The inscription cites the commemoration date of the building (184.108.40.206.13 10 Ben 16 Kayab, or 10 January AD 738), a few months before the death of this distinguished ruler. At the tops of the benches there were vertically-tenoned macaw heads, one along the central axis and one at each end of both buildings. These are also called 'markers', though their actual function during the game is not yet resolved. Earlier versions of the ballcourt also had playing-alley floor markers and vertically-tenoned macaw-head bench markers, indicating a continuity in decoration during the ballcourt's c. 400 years of use."
William L. Fash, Scribes, Warriors and Kings: The City of Copán and the Ancient Maya, p. 125-6