The pianist Matthew Schellhorn has given an interview on Messiaen, on whom he is an expert, and birdsong. Messiaen was fascinated by birdsong, and based numerous compositions on it. Matthew remarks:
While Messiaen found birds to be "sovereign" in their creative capacity, he also said they are "the closest to us, and the easiest to reproduce". I should assert that the only man-made music ever, perhaps, to come close to birdsong is Gregorian chant. This music, the music proper to the liturgy of the Roman Catholic Church, manifests the same flexibility of both melody and rhythm. There is even evidence to suggest that the Gregorian melodies we have written down were the basis, in fact, of improvisation – which of course further reminds us of the sounds of the natural world.
In antiquity and the Middle Ages birdsong was regarded a very significant. The above picture, from a Bestiary, shows a lion bowing to a cockerel; in Hamlet the theory that cockerels sing all night at Christmas time, banishing evil influences, as they do throughout the year at dawn, is recounted. St Francis preached to the birds, encouraging them to praise God for the natural gifts with which God had endowed them, by singing. And so, of course, they did.
It is interesting to compare the ordered spontaneity of birdsong and of Gregorian Chant.Singing Gregorian Chant has to be learnt, by human singers, but in learning to do it we reconnect with something very fundamental in human nature.