is my ducks male or female? video included?

[alibaba]

my ducklings are 2 months old. 1 pekin duckling and another cross of pekin and silver appleyard duck. plz tell me are they male or female. video link included thx

 

[alibaba]

direct youtube links given below:

 

[CelticOaksFarm]

If they go QUACK it's a girl, if they go whasp whasp then they are a boy.

 

[Amiga]

if they go whasp whasp then they are a boy.

THAT's the sound!

 

[zooweemama]

Girls! My drakes barely make a sound. A low raspy sound that is not loud at all. Your girls are loud.