I have a 3 month old Khaki (possibly mutt). He spends his days free ranging in the yard under my watchful eye. He seems to have accepted all the other birds that come in the yard except for a female mallard that comes to visit. She drives him crazy. When she visits, he runs around the yard like he is being chased, puffs up his feathers, and makes a lot of noise. She is very wary of humans and doesn't stay if I go out in the yard. He has no problem with any of the Muscovies or male mallards that visit. He even seems to like the neighbors Pekin ducks when they escape their pen and visit. Why is he so scared of this duck?