Iquitos Legends:

he Huancahui is a magical being that lives in the Amazon rainforest that appears in a form similar to that of a falcon. This supernatural creature is named the Huancahui because his cry sounds like someone yelling "huancahuiii, huancahuiii."  Additionally, the Huancahui is called the "laughing falcon" because his cry sounds somewhat like someone laughing.  He possesses magical powers and is even able to catch fierce snakes, upon which he is said to feed.

According to this Iquitos legend, if an Amazonian shaman is able to learn the song or icaro of the Huancahui, he can also dominate snakes just like the Huancahui does. However, if he fails to chant the song perfectly, he will be besieged by snakes and die. Properly sung by the shaman, his icaro will stunt a snake and defeat it, leaving it impotent and unable to bite.