Optics Mag is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Read more.

Do Birds Have a Menstrual Cycle? Do Female Birds Have Periods?

Last Updated on

house finch bird perching on a tree trunk

If you’re a person with a uterus, then you’re more than familiar with the agony of having a period. Whether it’s cramps, backaches, nausea, or an intense craving for chocolate, that time of the month isn’t the most fun of experiences. Do all animals have to deal with menstruation, though?

Take birds, for example. With their egg-laying, how closely do their reproductive systems resemble our own? Do birds also have a menstrual cycle? Do female birds have periods? The short answer is no. However, birds do ovulate, which is where the eggs we eat come from.eagle divider

Do Female Birds Have Periods?

Menstruation is simply the process of the uterus shedding its lining each month. It is part of the preparation for pregnancy in those who have a uterus. However, birds don’t have a uterus; thus, they can’t have periods. Instead of a uterus, most adult female birds have a functional left ovary and an oviduct.

Birds do ovulate, though. But instead of it leading to menstruation like humans, it leads to egg-laying.

barn swallow on the nest
Image Credit By: slowmotiongli, Shutterstock

How Do Eggs Develop?

When birds ovulate, they produce eggs (or ovums). These break off from the ovary’s surface and pass into the oviduct, which is similar to a fallopian tube. As the egg goes through this tube, it gets coated with yolk, then with albumen (the egg white), before being coated with membranes, and finally, the shell. The shell part of the egg is created right before the egg leaves the bird’s body.

If an egg is fertilized before it leaves the body, you get a baby chick. If not, you get a delicious egg you can eat for breakfast.

blackbird's eggs in the nest
Image Credit By: foto-augenblick, Pixabay

So, Are Eggs a Birds’ Period?

You might have heard people say that an unfertilized egg, like what we commonly eat, is actually a bird’s period. After all, an egg is the result of ovulation for a bird, so it makes sense, right? But that’s not true. Most of the rumors about eggs being a bird’s period seem to have come about from organizations like PETA.

Birds don’t have a uterus, though, so an egg can’t be a period. And don’t be concerned if you happen to find blood in an egg you’re about to eat. Again, it has nothing to do with periods and everything to do with the fact that even unfertilized eggs get prepared to be fertilized by developing yolks, membranes, etc. Blood found in an egg is simply the result of a broken blood vessel.

eagle divider

In Conclusion

Female birds aren’t capable of menstruation, as they don’t have a uterus. In fact, most adult female birds only have a left ovary and an oviduct. However, they do ovulate, which is a process wherein eggs are developed. But instead of the body getting rid of unfertilized eggs by bleeding, birds will lay eggs instead. That doesn’t mean eggs are a bird’s period, though! A bird’s reproductive system is only vaguely similar to a human’s system, so no uterus means no period.

Featured Image Credit: bryanhanson1956, Pixabay

About the Author Misty Layne

Misty Layne lives out in the woods in small-town Alabama with her two cats. She also has an array of stray cats, raccoons, and possums who like to call her front porch home. When she’s not writing about animals, you’ll find her writing poetry, stories, and film reviews and is excited to share her knowledge with you all. In her free time, Misty enjoys chilling with her cats, playing piano, watching indie and foreign films.