I have two 10 week old mallard, a male and female. The male is normally very shy and only goes somewhere if the female goes first. He did this weird thing today when They were both up by the front door of my house. The male started doing this strange trembling thing with his head and kind of attacked my leg. He did it a few times. He's never done anything like this before. Later he also ventured away from the female, which he's never done before. Is he expressing dominance?