Technical news site Ars Technica reports today that a controlled study of songbirds strongly prefer conventionally farmed seeds over organic ones.
Ars Technica notes that the conventionally farmed seeds had more protein, due to Haber-processed ammonia providing more nitrogen to the crop, while the organic ones had to get their own nitrogen from the soil. So it may be the case that what the birds are preferring is the higher protein quality, a major concern for a wild animal. (A good source of protein helps you heal injuries, keep your body in peak condition, and also make more of you. All things that animals want to do.)
Organic advocates shouldn't be insulted by this announcement, then. We humans have protein in pretty much unlimited quantities, so it makes sense for us to be a little picky about what we eat.