Sexing Call Ducks?

[lilrider]

I just bought a pair of call ducks along with some chickens from a lady off Craigslist. She actually ended up refusing my money as they just wanted a good home for them. Anyways they seemed to think it was a female and male. One is smaller more dainty than the other. Is there any way to tell? I believe they are youngish as well. Pardon the messy digs. I wasn't expecting to pick anyone up until later this week so I had to throw together temporary quarters. Old horse stall which I left some poop in that they are loving digging through (very old poop). They will be moved to a shed coop with run and pool next week.

 

[Wyandottes7]

Female ducks will be noisier than the males. They will make harsh quacking noises, while males are usually hoarser or don't make loud noises at all (more of a whistling, raspy noise). Also, once your ducks are mature (if they aren't already), males will develop sex feathers on their tails. These feathers are curly feathers on top of the tail feathers. There are usually two of them. Females do not develop these feathers.