* ocasa.org: An archaeological study of chirped echo from the Mayan pyramid of Kukulkan at Chichen Itza, withmp3 files of a quetzal and oftwo Quetzal bird chirps (recorded in a rain forest) followed by two chirped echoes stimulated by a handclaps at the pyramid"* Resplendent Quetzal videos, photos & sounds on the Internet Bird Collection
==References====Sources====External links==* ocasa.org: An archaeological study of chirped echo from the Mayan pyramid of Kukulkan at Chichen Itza, with audio files of a quetzal and of two Quetzal bird chirps recorded in a rain forest compared to two chirped echoes simulated by a handclaps at the pyramid