Someone asked me this question in general conversation a few days ago (you know, as people do when you advertise yourself as someone who has a keen interest in the genitals and sexual strategies of all animals). When you ask Google, the first link that comes up is one from the ever-knowledgeable oracle of wisdom that is Yahoo Answers.
Michelle needs to know how birds have sex cuz i mean she just dont see how???!!! FEAR NOT MICHELLE! LOZZA IS HERE 2 ENLIGHTEN U!
Now, birds are well known for their elaborate courtship rituals, from wonderful dances to building intricate and beautiful nests to impress potential female mates. However I won’t focus on courtship here – this post is just about the down-and-dirty how-do-they-do-it physical act of mating in avian species. I may focus on the more romantic side another time. Maybe.
From a young age, most of us are aware that birds (and bees, but we’ll get onto them another day) have sex. We’re told that they “do it”, but not how. This is unhelpful. Mother, don’t bother telling me birds and bees reproduce unless you can tell me HOW. Why have I never seen a pigeon with his penis out? Do pigeons even have penises!?
Well I’m here to tell you the details your parents failed to mention. Call it advanced sex education.
Penisless birds and the cloaca
The first thing to note is that the males of most bird species do not have penises (although many waterfowl species do, and they are STRANGE – we’ll come onto that later). Both male and female birds have an opening called a “cloaca” – which I thought was a rather lovely word, especially as bird sex is often described using the phrase “cloacal kiss”. Then I learned that the word “cloaca” comes from the latin word for sewer. Why would their sex hole derive from a word for sewer, you ask? Because birds don’t just use this hole for reproduction. They pee and poo out of it, too. Gross but effective, especially if you have to be light enough to fly.
During the breeding season, the ovaries of the female expand dramatically, as do the male’s internal testes (that’s right, birds keep them inside so that’s why you haven’t seen a blackbird with balls. Presumably makes flying much easier). Bird copulation need only last a few seconds, to allow the cloacas of the male and female to touch in this so-called cloacal kiss. The male typically mounts the female from behind, depositing sperm from his cloaca into the female’s. The sperm then may or may not fertilise the female’s egg, which she has produced in her one functioning ovary. In most female birds, only the left ovary develops into a functioning organ, again this is probably an adaptation to the need to be as light as possible in order to fly effectively. The egg develops a hard shell, is laid by the female and then incubated until the new chick hatches.
- The males of most bird species do not have a penis, both sexes have a multi-tasking orifice called the cloaca. Copulation generally involves a few seconds and a mere touching of these organs in order to deposit sperm.
Birds with penises
In the world of birds, penises are a rarity. In fact, only 3% of birds can boast a penis, and these species include large flightless birds like ostriches, emus and kiwis, and waterfowl like ducks. Bird penises are fundamentally different from mammalians in one main sense: They are erected by lymph (the fluid that circulates through the lymphatic system), not blood. The ostrich penis was until recently were believed to be different from those of other birds in that it was filled by blood, but it was recently confirmed that they too are controlled by lymph.
We can now move onto one of my favourite penises of all time: That of the duck. I don’t need to say much to justify my awe of this organ, just look at this very short video.
WTF IS THAT?! Spectacular is what it is. It looks like a corkscrew. It has SPIKES. Fairly little was known about waterfowl genitalia until the end of 2009 and there was a lot of coverage of the topic then so I won’t go into it in great detail (if you are interested I recommend my favourite article on the duck penis by Ed Yong which you can read here), and I want this to just be a primer on bird sex in general. But what I will say is that when you see a penis like that you should ask yourself WHY? Why would a species evolve such a bizarre penis? Because, my friends, it’s questions like these that separate the sickos from the scientists. Or that what I tell myself.
And for good measure, here is a picture of the duck penis alongside a duck’s vagina. Don’t say I’m not good to you.