At what age can you tell the sex of a duck?

[sandy sea]

I have two peking ducks. They are all feathered out, I think. When should I begin to see a little curl on the tail if I have a male? I read sonewhere that the males and female make a different quacking noise too, is that correct?

 

[sandy sea]

I just found out the answers to my questions, right on Backyard chickens. I should have looked at the other posts before writting.

 

[xfilesnumber1fan]

Only females quack..Boys sound quiet and raspy..I use able to tell by quack alone at 6 weeks they still dont have the curl or their male color yet they are 15 weeks.I can see the green coming in the heads..They are mallards