Confused on sex of duck

[Want Less]

A couple months ago we were given two Runner ducks that are about 1 1/5 yrs old. We were told they were both females. Neither is laying right now. They both look the same (no curled feather on either tail), talk the same (As far as I can tell, they both "quack"), and are the same size. They are inseparable, never more than a couple feet away from each other, and they are kept with our free ranging chicken flock (~20 hens and a rooster). The ducks definitely rule the flock, including the rooster, and herd them around if and when they want. They are never aggressive toward people, in fact they have very limited handling so they flee when you come around.

However, randomly the other day I caught the two ducks mating...! I started researching and reading up about sexing ducks, and I can not find anything "boy like" about this duck that was mounting and breeding the other. Now, granted, I saw this from my kitchen window and was about 25 feet away but there was definite mounting, tail flaring, you know the drill... and then happy dance in the pond immediately afterward (LOL)

So I'm confused. The previous owner has no idea if this one particular duck was ever laying. Could it be a boy in disguise? Or do my girls just really like each other? lol

 

[jdywntr]

Females will also mount eachother. Drake curls can be pulled out. At this age, you can sex by voice. Females have a definite quack while boys have more of a rasp. In Storey's Guide, they describe the male voice as an "elongated wongh". Males don't make the harsh quack.

Otherwise, when you see them "mating" you can watch to see if there is a male. The penis does not go back in right away. This is what I did with my geese. Its a little weird though to sit there and move yourself for the right angle.

Because of the season, they probably won't start laying until spring. If you get 2 eggs in a day then they are both girls. If they recently molted, the drake curl could come back in.

In runners, there is a size difference between sexes and may be a difference in coloring.

 

[Want Less]

Thanks for the response! I have been keeping an eye on them hoping to catch them in the act again, but so far nothing. And they are so weary of people, I'm sure they won't do the deed if I am out in the yard anyway.

The two ducks look identical with the exception of beak color. The possible boy has an orange beak while the other has an army green beak. So at least from a distance of my kitchen window I am trying to notice behavior differences between the two, since if I go outside they are more concerned about watching me.

I don't think that they have molted (at least they havent since they have been here, and the previous owner didnt mention a recent molt).

I've been trying to pay attention to their voices, and as far as I can tell they both sound the same. Hopefully this spring will tell us I guess!

Females will also mount eachother. Drake curls can be pulled out. At this age, you can sex by voice. Females have a definite quack while boys have more of a rasp. In Storey's Guide, they describe the male voice as an "elongated wongh". Males don't make the harsh quack.

Otherwise, when you see them "mating" you can watch to see if there is a male. The penis does not go back in right away. This is what I did with my geese. Its a little weird though to sit there and move yourself for the right angle.

Because of the season, they probably won't start laying until spring. If you get 2 eggs in a day then they are both girls. If they recently molted, the drake curl could come back in.

In runners, there is a size difference between sexes and may be a difference in coloring.