How Do Birds Mate? (SURPRISING Answer + Explanation!)


Chances are, you’ve thought to yourself: “How do birds mate?” I was equally as curious as you, to be honest. I found very little information about it online, so I did my own research and found some answers. Here’s what I found:

Most birds mate in a process known as the cloacal kiss. During sexual intercourse, a male bird will attempt to mount the female on her back as the female bends forward and lifts her tail to one side. The cloacal kiss happens when the male cloaca and female cloaca meet with a transient touch.

Sounds interesting? I’ve actually written lots of surprising facts you didn’t know about bird reproduction that you won’t regret reading. Read on to find out more!

How Do Birds Mate?

So you know that birds mate using a process known as the cloacal kiss. But what does that all mean? Here’s where I come in and explain everything!

Did you know: The act of sexual intercourse in birds is quite different from human sexual intercourse?

Yes, it’s true! Male birds do not have penises male humans do. Instead, they have an opening known as the cloaca that will come in contact with the female cloaca to transfer his sperm to the female bird.

Okay, enough words. Here’s a video showing the entire process. It’s really quick so don’t miss it!

Most birds mate in a process known as the cloacal kiss. During sexual intercourse, a male bird will attempt to mount the female on her back as the female bends forward and lifts her tail to one side. The cloacal kiss happens when the male cloaca and female cloaca meet with a transient touch.

The Clocal Kiss

Birds engage in coitus with a technique known as the ‘cloacal kiss. This is how the procedure works in most birds:

  1. First, the male would perform his mating display.
  2. Then the female will give some form of indication to the male, and stoop a little lower for the male to mount.
  3. The male bird will then take the cue and mount on the female.
  4. Next, he will slowly lower his body and use his tail to sweep or brush aside the tail of the female bird. The female bird responds by lifting up her tail.
  5. Eventually, the cloaca of the male bird will meet the cloaca of the female bird in the phenomenon known as the ‘cloacal kiss’.
  6. The sperm from the male cloaca will be transferred to the female cloaca and go into the oviduct where her eggs will be fertilized
  7. Hooray! The birds have successfully mated!

Here’s a video of the cloacal kiss in slow motion:

Now, here’s a fun fact:

During the breeding season, hormonal changes in both male and female birds can actually cause their reproductive organs to increase in size and efficiency!

For example, male testes can swell to more than 1000x their usual size, and female ovaries and oviduct expand in size in preparation for egg fertilization and laying eggs.

Here are some videos of a peacock/peahen and pigeons performing mating rituals and a cloacal kiss.

Ducks Mate Differently From Other Birds

Mating on land already has a very low success rate due to the inefficient transient contact of a cloacal kiss.

Ducks have found it much more difficult to mate because they are constantly on the waters.

In order to have a higher fertilization rate, male ducks have adapted to develop penises! This is a rarity as 97% of ducks don’t even have a penis!

Every year, male ducks develop a completely brand new penis when daylight changes signal the onset of the breeding season. That’s when their genitals start to grow in size.

However, when breeding season is over, they shrink back again. What’s even more peculiar is the shape of their penises!

Here’s an interesting video I found on this:

Why? Why the excessive penis structure?

Genital Morphologist Patricia Brennan has discovered in her duck genitalia studies that female ducks have long corkscrew vaginas that spiral in the opposite direction of the male duck penis.

Here’s how that looks like:

Female mallards have twisted vaginas that make intromission by unwanted males difficult. The male penis spirals in a counterclockwise direction while the female spirals in a clockwise direction
Source: Catherine Delphia

Female mallards have twisted vaginas that make intromission by unwanted males difficult. The male penis spirals in a counterclockwise direction while the female spirals in a clockwise direction.

patricia brennan

Despite the male duck’s attempts to control and force copulation success, the female ducks get to keep it! You go girls!

Fertilization

After birds perform the cloacal kiss, the mating process doesn’t end there! Fertilization then begins.

Both birds assume that the sperm has entered the female’s body once the cloacal kiss happens and they start to get ready to build a nest/get ready for hatchlings.

But what actually goes on behind the scenes in the female’s body? 

Here’s what happens: Sperms enter the female’s cloaca and proceed through the uterus to the oviduct. (Refer to the diagram below).

The sperms will meet the yolk that was produced in the ovary in the oviduct and be fertilized there. The sperms will then enter the yolk and begin the formation of a fertilized egg in the oviduct.

Also, if you are looking for a visual aid on how the yolk travels in an avian female reproductive system, then have a look at this video. One thing though, this video does not include fertilization of the yolk.

Oh, if at this point, you want more information regarding bird mating processes, do check my other article on bird mating and reproduction, written in simple, easy-to-understand terms like this post!

In it, I include interesting mating calls, mating rituals, and the entire life cycle of bird reproduction.

It’s full of digestible information and definitely worth reading!

Final Thoughts

Did that finally satisfy your curiosity?

Birds are indeed weird creatures when it comes to sex, with their cloacas and corkscrew penises! Cool sexual techniques aside, birds are still amazing creatures to learn about, because they are everywhere!

So next time you see a pair of birds mating, you know how that works!

Thanks for reading and happy birding!

My Recommended Birding Resources:

Hey there, Justin here!

Here’s a list of all my favorite resources, products, and all brands I trust and love.

Although some may be affiliate links, I will only recommend those that I think are of great value. Simply purchasing using the links helps to keep this blog running!

  • My Binoculars: The pair of binoculars that I personally use is the Celestron Nature DX 8×42 Binoculars. It’s a great budget pair for beginner birders. Highly valued for its price! Read my review here.
  • Safe Paint for Bird Baths: Not any paint can be used to paint bird baths. Links to all safe paint for bird baths are in this article I wrote!
  • Sealers for Bird Baths: Not all sealers can be used to paint bird baths. Links to all sealers for bird baths are in this article I wrote!
  • Safe Paint for Birdhouses: Not any paint can be used to paint birdhouses. Links to all safe paint for birdhouses are in this article I wrote!
  • Birding Apps: 2 of my favorite birding apps are Merlin Bird ID, and eBird Mobile! Merlin is great for tracking and identifying birds, and eBird Mobile is great to track the birds sighted when birding. Read a post about them here.
  • Birding Websites: I’ve compiled a list of links to my top 10 recommended birding websites in a blog post. Find the links here!
  • Birding Podcasts: Birding podcasts are a great way to learn about birds. Links to the top 8 that I recommend can be found here!

Alternatively, you can check out my resources page here where I’ve compiled all the links to the above!

Justin

Justin is a hobbyist birder that hopes to share his birding knowledge with the world. His favorite bird is the Large-tailed Nightjar and he really loves potato chips!

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