It was once thought that Chimecho were found on Mount Pyre because it is the tallest mountain in Hoenn, and therefore the shortest distance from Heaven. Today, the most common explanation refers to wind currents; Mount Pyre is where Chimecho caught in the winds, lighter than air, will inevitably, eventually land.
It is this population of Chimecho that accounts for the mountain's fast-paced, energetic, yet harmonious melody – a melody that has undoubtedly pulled many monks and priests its way. The Chimecho are not gregarious like when hanging from the roofs of shrines, as they were before the wind carried them away. Yet although never quiet, they shift shyly through the grass while their song echoes across the mountain. Perhaps it is their rarity that accounts for the old idea that one can only catch a Chimecho when they have first achieved enlightenment, one diminished in recent years by the capture of this pokemon by pokedex holders for study.
Interestingly, the reputation of Mount Pyre as a holy place predates the enshrinement of Kyogre and Groudon's famous orbs. It appears that the original source of this belief came from the human tendency to ascribe tall peaks to the gods, one reinforced in this case by the Chimecho; a singing mountain where a pokemon used as ornamentation for religious buildings can be found in the wild must truly be a holy sanctuary.
Yet if this is the origin of Mount Pyre's holiness, the Chimecho inhabited this mountain long before they were used as ornamentation, even if the wind currently magnifies their number. If Mount Pyre is Chimecho's natural habitat, and not a colony of feral pokemon long extinct in their original home, maybe they really did fall from Heaven to play the melody of the gods on Earth.