"Soon Holtz came to see where the various predominating pitches in birdsongs could be calibrated by reference points on the musical scale and their harmonics. Dan Carlson had instinctively hit upon frequencies that were the ideal electronic analogues for a bird choir. "It was thrilling," said Holtz, "to make that connection. I began to feel that God had created the birds for more than just freely flying about and warbling. Their very singing must somehow be intimately linked to the mysteries of seed germination and plant growth."
"Looking for western music in the range of Carlson's highest frequencies, the ones which in Hindu experiments had shown the best bumper crops of corn, Holtz culled several baroque selections from "The Dictionary of Musical Themes", settling on the first movement of Vivaldi's "The Seasons", appropriately called "Spring". "Listening to it time and again", said Holz, "I realised that Vivaldi, in his day, must have known all about birdsong, which he tried to imitate in his long violin passages."