Aggressively sexual mallard mix

So I've recently realized that I may have a bad male to female ratio in my flock.. We have three drakes (two immature crested, one wild mallard / runner mix) and three hens (two immature crested and one Cayuga / runner mix that is about to sit on a nest).

The male mallard / runner mix has suddenly become very sexually aggressive, despite being mature for a few months now. He chases and mounts all of the other ducks regardless of sex, literally chasing them around the yard as fast as he can and pinning them down and mating with them (or trying, in the case of the males). He even tried to mount my huge Sebastopol goose.

Are all of my drakes going to get like this at some point?! I really don't want to part with any of the drakes - they're our pets and we're really attached to them - but I really don't think I can get any more females any time soon. Will the females be ok with this ratio? They are free range except for (obviously) at night.

Here are some pictures for fun

One of the crested drakes... he was incorrectly sexed. His name is Ladybird he has one blue eye and one brown eye!


The crested ducks - the white one is the other drake.


Some of the flock.


Thanks for your help!

He may be dealing with raging hormones right now because of the start of mating season. You should consider separating him from the others before he hurts one of them. I think normally you would put him in with the other males so he wasn't lonely but it doesn't sound like that would stop his mating behavior. If he manages to penetrate one of them it could be bad. He won't be happy to be separated but it is your responsibility to keep the others safe. You may consider looking into castration for the long term if your not planing on breeding. But generally drakes get calmer as they get older.

You're right that your ratio of drakes to hens is way too high. When the other two drakes reach maturity they may show the same behavior. You could potentially have a situation where all three gang up on one hen and kill her. You either need to increase your hen count to at least 9, get rid of two drakes, or separate the drakes completely to where they can't see or hear the hens. I know it can be tough but you have to consider the safely and happiness of the hens.