Reply to Jan: I don't know much about duck mating rituals, but I know that birds fight viciously, and that this is often emphasized in captivity. This was brought home to me last week when I discovered that one of my daughters' schoolfriends had just had six of her seven chickens killed by a fox. The birds were left out too late and the fox took advantage. The only one to survive was the only one which had been penned up, because she was being pecked by the others.