Do Birds Have Periods? Why Some Birds Bleed From Their Privates?

Do birds have periods, or is life easier for avian females? Let’s understand the reproductive cycle of birds and how they produce eggs.

The dreaded monthly menstrual cycle is something females have always had to face whether you are human (Homo sapien) or any other mammalian species.

But, have you ever considered whether birds experience ‘periods’ or menstruate like other mammals?

With over 10,400 extant bird species all over the world, you would presume that the females would have had to menstruate and have a period to expand the species to such an extent.

Do Birds Have Periods

Short answer, no, birds do not have periods and their reproductive cycle is very different

Female birds do not have a uterus therefore indicating that there isn’t any shedding of the uterus lining producing a period.

However, both parrots and hens confuse people when considering if they have periods or not. We will discuss them specifically later in this article.

But before doing so, understanding the anatomy of the avian reproductive system is key to then comprehend why periods are absent across avian species and how they reproduce.

The Avian Reproductive Systems


Across all avian subspecies, males have two testes located within the abdominal cavity of the bird.

Unlike mammals, the male’s testes and spermatogenesis, where the sperm is fertilized, occurs at body temperature.

Within the testes are a number of intricate ducts that connect to ‘paired vas deferens’ muscular tubes that transfer sperm to the copulatory organ. 

This is then where internal fertilization occurs as bird species. In short, apart from ducks; ostriches or emus, birds do not have a penis.

Do Birds Have Periods


Different from mammalian species, female avian species don’t have a uterus or cervix. Instead, the lower end of the oviduct of female birds opens into the cloaca which is also connected to the reproductive, digestive and urinary systems.

Interestingly, avian species only have paired ovaries up to 5-10 days post-hatch.

The right ovary and fallopian tube then retreat leaving the bird’s left ovary and fallopian tube functioning where yolks are released to then be fertilized.

However, some birds such as hawks and owls have both ovaries intact and yet produce fewer eggs than a hen does with a singular ovary.

Scientists are yet to produce an explanation for this particular physiological difference.   

The Myth of Menstruation in Birds

Mother nature herself is a mystery, but so has been concluding whether or not bird species have periods or not. 

As previously mentioned, animal biologists have concluded that birds do not experience periods like we humans or other mammalian species have. 

But, some species stand out such as the hen who produces eggs that we presume are their periods.

And parrots, who have been known to ‘bleed’ by their owners and therefore established to experience a type of period.  

Do Birds Have Periods

Are Eggs Really Chicken Periods?

As previously explained, birds and especially hens, do not have a uterus. Therefore, they cannot release endometrial blood and have a period. 

Yet, many people across society still believe that their eggs are in fact their period. 

Instead, their eggs are ovulated follicles that travel through their bodies and are laid either fertilized or unfertilized. This whole process begins with a single cell that grows into an oocyte, otherwise known as a yolk.

When fully mature, this yolk is released into the peritoneal cavity where it awaits fertilization. 

After developing membranes and albumens, the egg-white, a hen’s egg develops into its oval shape where it then passes down the shell gland.

Calcium and other minerals are added whereby the entire egg shell is formed to then be laid by the hen via their cloacas. In essence, an avian egg is a secretory by-product of their reproductive system but not a period.

Do Birds Have Periods

Do Female Parrots Have Periods?

The closest thing to concluding ‘yes, birds do have periods’ has been found from studying the parrot species. 

Many owners have assumed that their parrot is having a period when they have observed blood on their feathers around their body. 

However, little did they know that parrots actually shed their feathers during and after hitting puberty in a process called ‘feather bleeding’, at around 6 months to 1 year old.

In a way, it is similar to a period but cannot be termed one as periods are associated with a uterus that parrots such as cockatiels, parakeets and budgerigars do not have. 

To attain bigger and better ‘grown up’ feathers, parrots shed them during puberty causing the blood vessels to break down, open and bleed.

How Do Different Species of Parrot Reproduce?

Parakeets: Instead of periods, parakeets go through a hormonal chapter during which their estrogen and testosterone levels rise.

Following this a single parakeet will mate with its pair whereby the female will lay a fertile egg.

Cockatiels: Interestingly, similar to hens, cockatiels can reproduce infertile eggs without a mate. 

However, during their breeding season females can produce up to 5 fertile eggs at a time and surprisingly same-sex cockatiels can also go through motions of breeding. 

Do Birds Have Periods

Why is My Bird Bleeding From Her Privates?

Otherwise known as cloacal bleeding, when owners notice blood around their birds’ privates, it’s most likely a prolapse due to egg laying issues or other cloacal masses. 

Of course, you can understand that people confuse this for a period but as this article explains birds cannot experience periods as we know.

Instead, it’s more likely to be a medical condition that a veterinarian can cure.


Research proves that birds cannot have periods like mammalian species, but their reproductive and breeding systems certainly vary. 

The article concludes that birds can’t have periods or a menstrual cycle as they do not have a uterus and therefore cannot shred an endometrial lining that mammalian species do.

The confusion that eggs are hen’s periods and feather bleeding in parrots suggest that they have periods will continue to persist amongst owners and scientists. 

However, from studying the anatomy of various birds it’s interesting to understand how they can in fact reproduce without a period occurring. 

Hens release a yolk from their ovaries which eventually becomes a hard-shelled egg that can either be fertile or not. Parrots hit puberty and shred their feathers which makes them bleed and reach a reproductive age. 

Adding to the confusion are medical conditions such as cloacal prolapses that will continue to make owners believe their bird is experiencing a period but the science proves that they cannot.

Perhaps one question we should all consider is what came first, the chicken or the egg?

Gordon Ramel

Gordon is an ecologist with two degrees from Exeter University. He's also a teacher, a poet and the owner of 1,152 books. Oh - and he wrote this website.

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