Boy ducks girl ducks

[Heidihen]

Hi i have 5 ducks And ive seen them mateing There are2 boys and 3 girls i think but do you know how to tell a Boy duck from a girl duck please tell me that would be a great help

[Mike]

Well depends on the type of duck, such as mallards and rouens have color differences. Every breed though, males have curled tail feathers and male a lower quack than females do. Females are much louder and make a more distinct quack in my opinion.

[Heidihen]

I have chery vally ducks they are white but still i dont know wich is a girl or a boy

[millipede]

I hadn't heard of cherry valley ducks so I googled. I didn't google long but what I saw looks like those are similar, or the same, as our pekins here in the US.
As Mike said, the males will usually have curly tail feathers and the females wont. And also like he mentioned, there's a different in the quacking.
In general, at least in my own experience, the birds you see trying to mount the others are bound to be males. But the birds that get mounted aren't always necessarily females. Ducks sometimes jump on anything that walks by and to me it seems like a dominance thing.
Any chance you could post some pictures of your birds?

[Katsotse]

You can either-

a) Look at their tails. Is there a long, culy feather protruding? Then, chances are it's a male. However, some of my Runner Drakes didn't seem to have these "Drake Feathers", or at least they were hard to find.

b) Listen to the quack. I determined the genders in my flock by picking up the ducks one at a time and listening to the quack. If it's a loud, ringing, classical quack, it's female. If it's soft, raspy, or kind of like a cough, it's a male. Sometimes, though, they dont seem to want to quack at all! My "head of flocks", Phelps, is very soft-spoken for a Runner and never seems to quack for me. I can sometimes tempt him into doing so, however, by carrying him far enough away from the rest so that he calls out to him, or I bounce him gently.

c) If you're REALLY desparate, you can vent-sex them. Google it. I'm not really keen on explaining it. LOL

Best of Luck!