Mule ducks: how do you spot them and sex them?

[Tatum hills]

I have hatched my first ever lot of ducklings last October and I know 2 of the 8 will be mules as their dad is a mallard breed (crested drake) and mum is a Muscovy. I was told it'd be obvious who the mules are but not to me Six of the ducklings now make a definite QUACK, but 2 are larger than the rest and make a funny noise which sounds more like a Muscovy than a drake to me. My questions are :
1. Do drakes take time to perfect their call like cockerels?
2. What sound and other features do mules have that may help me identify them?
3. If the mules don't quack, how do I sex them?

 

[learycow]

Do you have pictures?
Mules are quite obvious as they don't look like muscovy or a mallard derived breed. And like pure muscovies, mules can be sexed by their size with males being larger than the females.

Here are some that I have hatched:

Female


Male (can really tell the difference in size in person)


All females

 

[casportpony]

Great mule duck pictures @learycow!

 

[Buck Oakes]

Well if u only had babies from her and that male then all are mules

 

[sourland]

Oh my gosh that is hilarious. I think my Muscovy ducks would probably try to hatch apples, those girls are nuts.

Of course the story did not end there. Once I located her nest, I gave her some fertile eggs.

 

[Miss Lydia]

Of course the story did not end there. Once I located her nest, I gave her some fertile eggs.

Aww what a nice guy.

 

[sourland]

Can you post pictures? If they are 'Quacking', they are not pure muscovies.

 

[Buck Oakes]

True and also ducks esp Muscovies can have offspring from different fathers so if u do have a Muscovy male as well then some babies could be pure bred Muscovies.

 

[Buck Oakes]

Also it's hard for mules to actually be bred, only some percent of eggs are actually fertilized, I think 60% but then more are lost because they're anatomy doesn't match the Muscovy hens eggs size, or the offspring are to frail and can't even hatch so if u got a good portion of mules then great

 

[Tatum hills]

Thanks for your replies but there seems to be some confusion. I don't have a Muscovy drake, so I know none are pure muscovies but my question is: do the Muscovy x mallard quack or not? And if not how to you sex them? I know mules are sterile which is why I am trying to work out who's who as I don't want to sell a mule to a breeding home.