Usually the male will have more green or color and is larger than the female.  There are blue cayugas and also green cayugas.  It sounds like you have two males.  As they get older, the female usually gets more white feathers while the male retains the green hue. 

An easy way to tell male from female (for me) is their quack at a younger age like your two are. The drake will whisper and the females will have more of a pronounced quack. I have raised duck for years so I have gotten pretty good at it. The hens of a Cauyga will have the shine to them as well. Another way to tell is by their tail feathers. Males get the curel.(sp) I am not sure on all domestic brreds if they get that?? I raise flying mallards and have had domestic in the past but love the mallards more.

 

Good luck

Goldy_

I know with mallards the males will have solid colored feet (orangey) while the female may have some black spots on it.  This goes the same for the bills...the male will have a solid colored bill (olive) and the females bill will be spotted.

 

The curl will not appear until the adult feathers are in.  The quack is a good way of distinguishing a male from a female duck.

 

It is funny because I guessed the wrong sex on all of my ducks when they were babies.  I had to change the names which were originally Nellie to Neddie and Willy to Wilma.  I left Skippy's name the same.

 

I discovered the mistake when they lost their baby fur and got their adult feathers in.

 

Please let us know what sex they turn out to be!

Thanks so much everybody for the info on my Cauyga's.  I'm now pretty sure (95%) that I have a boy and a girl,  my girl has white feathers, not alot just a few, and while she isn't very noisy, ( my khaki campbell girl, Daisy talks so much it's difficult for any of the others to get a word in edgewise) I sat with them the other day and did see/hear her quacking a bit.  Thanks again for the great info.  Hopefully Jack and Jill will be proud parents next spring.  Have a great weekend.

Melissa

Hi Melissa, so glad it turned out you have a male and female.  Hope you have lots of babies with them.  Did you name them Jack and Jill...so cute!  My Khaki Campbell is so noisy too.  I wonder sometimes how my poor male duck, Neddie puts up with the two quacking females.  Sometimes they are non-stop.  If you can, would love to see pics of your babies.  Thanks for posting...Michelle