Can Ducks Change Genders?

Biology is an absolutely fascinating subject. For all our study and all our research, will we ever know all it’s idiosyncrasies? Learning about all of the amazing, minuscule ways our bodies and nature function is really just mind boggling.

I was very interested when I realized one of nature’s quirks could be developing in my very own backyard. One of our ducks appears to be changing its gender (or at the very least is quite confused)! At first I thought I was imagining the drake curl developing on my female duck, that it must have just been some strange, mislaid feather or molting issue. Then I watched all of our ducks interacting – and then I did some research to see what could possibly be going on.

I had read before that birds could occasionally change sex, but I never expected to see it myself. Without getting too technical, almost all female birds are born with two ovaries, but only the left one functions.  The right ovary never develops beyond a clump of cells in most females.  If the left one becomes damaged, diseased, or for some reason shuts down, the female bird is no longer producing oestrogen (the hormone in birds responsible for female characteristics).

Sex Chromosomes in birds

Sex chromosomes in birds are expressed as Z & W, with all birds “defaulting” to ZZ (male) and the presence of a W chromosome making a female.  With no oestrogen being produced, the rudimentary right ovary can actually begin to develop into a functioning testis, can produce testosterone, leading to the normal physical male sex traits. This includes male plumage, growing male reproductive organs (did you know male ducks regrow a new reproductive organ every year??) and even sometimes the ability to fertilize eggs! Want some more information & examples on cases of birds changing sex? Click here for articles from BBC , Live Science, Phys.org and NBC News

It is not just limited to ducks but can happen in most birds. It is well documented (and not even that rare) in chickens for a female hen to grow spurs and start crowing. She may or may not continue laying eggs. Often this is in female-only flocks where the lead hen begins to take on some characteristics of a rooster. In extreme (and rarer) cases a hen will molt into male plumage and possibly successfully fertilize eggs.

Angelica’s journey

Angelica is a gorgeous white crested duck. She has always been a really large bird, nice and plump, very friendly and curious. We got her in June 2016, the first year we were raising ducks. That year we had just a small flock of 3 females and 1 male (all different breeds). Look how cute she was!

We purchased her from Metzer Farms as a day-old duckling. They have been around a long time, have a great reputation, and know their stuff. They have experts there to sort out the males and females for their customers. Mistakes do happen, but for all accounts, this bird should be female.

And she was. In writing this article, I was combing through the hundreds (maybe thousands lol) of photos I have of my chickens & ducks trying to pinpoint when the changes began happening. Luckily, Angelica is the only white crested duck we’ve owned. Picking her out in photos has been easy. She has also always been curious & interested in getting her picture taken, so I’ve got a lot to choose from!

Even in her lanky, awkward “teenage” phase, she was still a cutie! Her best friend was (and still is) Peggy, a Cayuga female.

By fall 2016 she was a full grown lady (see next photo at nearly 5 months old). She started laying eggs right about now and while she was not an everyday layer, we got at least a few a week from her.

She spent most of her time with Peggy. Our other two ducks, a Blue Swedish female and a Welsh Harlequin male, spent most of their time together. During that first winter the four bonded and afterwards traveled the yard as a flock of four. When winter ended and the mating season was beginning, our male did his thing. Angelica was quick and also naturally bigger than him because of her breed so would often try to scare him away. It didn’t stop him from trying though! Male ducks are pretty persistent when it comes to mating.

Drake Curls

The next photo is the first one I found with the beginnings of a drake curl. A drake curl is the curly feather (or often a few feathers) found at the base of a male duck’s tail. It is sometimes called the sex feather. It is one of the defining physical characteristics of male ducks of most domesticated breeds. In many duck breeds, the males have flashy, colorful plumage and the females are drabber colors.

With Angelica’s breed, White Crested, the drake curl is actually the only feather pattern difference between males & females – they are all a snowy white so it’s impossible to say if she has taken on drake coloring. Just behind Angelica in this photo, you can see our drake, Alexander, with a couple curly tail feathers. Angelica’s “curl” was barely a curl here, it was more like a loose feather just starting to lift away. At this point I definitely thought it was just a stray feather that would molt off. This was December 2017 when she was 1.5 years old.

Spring 2018 came and her curl got more and more pronounced. It was hard to miss (the next photo is from June 2018). This was when I started really paying attention. I sat and watched the ducks often, but now I really paid attention to see how they were interacting. I never saw her lay any eggs or hang about in the nesting area anymore. With three possible egg laying ducks it’s hard to say whose eggs are whose but for the entirety of 2018 there was not a single day where we had three duck eggs.

So I would wager she was not laying eggs anymore. Alexander was in the throes of mating season, but he wasn’t going after Angelica at all. He would chase after her sometimes with his head lowered as if to chase her off. The two females didn’t really act any differently toward Angelica, and she didn’t act any differently toward them. She just went about her day, minding her own business, happy to not be a part of the mating season craziness.

Voice sexing ducks

Aside from the drake curl, there is another reliable way to tell male from female ducks. If you listen to them “talking”, male ducks will have a much lower, raspy-sounding quack and females will have a much louder, clearer quack noise. Angelica still had the female clear quack noise. click here to read more about voice sexing ducks

With Angelica not part of the mating scene, there was one less female for Alexander to spread his “love” to and we started thinking about expanding our flock. A friend had some ducklings she was giving away so we brought one home, then about a month later our two female ducks sat on & hatched several eggs from a communal nest. Of the 8 ducklings that hatched there were some ducklings that were black like our Cayuga, some that were brownish grey like our Swedish, but zero little yellow ducklings that would indicate Angelica was their mom. This reinforced my belief that she was no longer laying eggs. Unfortunately only one duckling survived (a horrible sad story, if you would like to check it out here) – and unfortunately the free duckling and the surviving duckling both ended up being males.

Angelica was the first duck to befriend the free duckling, acting as sort of a surrogate mom, taking care of him. This again was female behavior, males will often try to chase off new ducklings (and our drake did this for a solid month with the new duckling).

So here we are now Spring 2019 and the beginning of another mating season. Now we have three males, two females and Angelica. Not great odds for our ladies. Her drake curl is still very present and has now stuck around through two moltings. The females have resumed laying eggs for the season, but we still have not had 3 in one day, so I am pretty positive she is not laying eggs. She is never in the nesting area.

She is definitely our heaviest duck, usually something that would indicate a male (although not sure it means much with all our ducks being different breeds). None of the three male ducks ever try to mate with her. They treat her like one of the boys, running her off occasionally. But she still has her clear female quack, and she never tries to mate with any of the females.

Here is a short video of her from late March 2019. You can hear one of our drakes with his raspy male quack off in the background in the beginning, and then also Angelica’s clear female quack.

Another way to identify duck sex would be vent sexing – opening up her cloaca to check for an internal phallus. If you are not experienced with doing this, you can seriously injure the duck. I am not experienced in it so it’s not worth the risk to satisfy my curiosity. I’ll continue to keep my eye on her for any other signs from my gender bending duck, but for now she seems happy & healthy. It could simply be a really early case of duck menopause causing her hormones to be out of whack.

In the end, it doesn’t really matter to me if Angelica is male or female or if she lays eggs or not. The ducks are mainly here as our pets, not to feed our family. She (or he) is an awesome duck, hilarious and curious and always the first duck to greet me looking for a little treat.