Hi Joe,about the origins: In my little Spanish songbook for the use in German schools for Spanish lessons I found as countries of reference Mexico/Castilia/Vizcaya.
Two stanzas given: De colores ... and Canta el gallo...
Translation of commentary: "A similar song is sung in Spain. In Mexico it worked further on. De colores sounds like a popular hymn to the beauty of nature, into which man is embedded. When the underpaid Mexican farm workers in the south of the USA intonate during their strikes, it also gains a political dimension..."
Unfortunately, the editor doesn't giv a reference to a scientific collection where he got it from.
Ehlers, Klaus:¡A cantar! / Klaus Ehlers, Elinor Haase, Bernhard Schmidt. - Stuttgart : Klett, 2000Best regards Wilfried