I've been having the same problem the past two weeks with my 20 wk old drake. At first he just seemed to be asserting himself by chasing me and my boyfriend around the yard and "yelling" at us when we come near the females, but now he's being downright aggressive. He has been nippy but he got ahold of kevins sweatshirt the other day after he lunged across the pool, he's been nipping my toes, and this morning as I was refilling thew water dish be lunged and bit my hand so hard its bruised. I gave him a tap on the rearend and told him no. My ducks have just recently become sexually active so is this just a phase? Is he just being protective? Do I mount him only when he bites and immediately after, or on a regular basis till it stops? Also is it normal for him to be mean when he's mounting the ladies? He gets up there pushes their necks down but right as he's getting off them he will grab them in the face area and latch on for a sec. It looks like he's hurting them but I'm not sure to stop it or not.