Collared Trogon Trogon collaris has most recently been assessed for The IUCN Red List of Threatened Species in 2016. The collared trogon's song varies geographically. The Mexican and Central American populations sing "a plaintive 2-3 noted kyow'-kyow or caow' caow, and a faster kyow kyow-kyow". South American songs are described as "a series of mellow whistled notes, usually with a stuttered introductory note: whi'whi whew-whew-whew." Calls include "a prolonged charr" and a "snorting chur-r-r-r". For sound from Bolivia, check > https://xeno-canto.org/685676