Do Birds Pee: An Ornithologist Answers an Interesting Question

We all know from childhood how cats and dogs, cows, horses and even elephants go to the toilet. Without exception, everyone has encountered the absolute lack of "toilet etiquette" in birds, whose feces can end up anywhere. But you have probably asked yourself at least once in your life: how do birds pee? It's time to get an answer to it, and the most competent one - from a representative of official science.

Dr. Sushma Reddy is an Indian ornithologist, head of the ornithology department at the Bell Museum of Natural History in the American state of Minnesota, and knows almost everything about birds. That is why journalists turned to her with a burning question. The scientist did not hide anything and revealed the bird secret using simple, understandable words.

Unlike mammals, which separate urine and feces, birds excrete everything at once. When a bird needs to defecate, it expels a white paste through its cloaca. Their body does not waste water on diluting the waste, but excretes it all together from the cloaca. This white paste is nothing more than a mixture of feces and urine.

Birds produce urine, but it is not like that of mammals. Over millions of years of evolution, they have adapted their excretory system perfectly for flight. Sushma Reddy says that the urine of birds is not liquid.

The cloaca is a universal opening that is responsible for excretion and reproductive function. The reproductive organs, intestines, and ureters come out of it. Birds do not have a bladder, and urine enters the cloaca directly from the kidneys. The cloaca is not only a feature of birds. It was found in dinosaurs, and is found in reptiles, amphibians, some fish, and even platypuses. From an evolutionary point of view, this method of excreting waste is an adaptation to flight.

Birds fly, which means it's important for their bodies to be light. Unlike mammals, which convert toxic ammonia into urea and dilute it with water, birds convert waste into uric acid, which doesn't dissolve in liquid. As a result, they simply don't need to carry around a heavy bladder.

This mechanism helps them save water and maintain lightness even during long flights. But, as it turns out, everything may be more complicated than it seemed before.

But there are exceptions to every rule. The same is true for birds. Some species have retained the ability to write in the truest sense of the word. One of them is the tiny tropical hummingbird. They feed on nectar, which they extract from flowers with their long beaks.

The kidneys of these birds break down nectar into nutrients and water, which is immediately expelled through the cloaca. Hummingbirds have an incredibly fast metabolism and urine is excreted 10-20 minutes after feeding. It is liquid, transparent, odorless and there is very little of it. So if you find yourself in a place where these little creatures live, their urine is the last thing you should worry about.

In 2020, a study was published in the Journal of Ornithology in which scientists analyzed the urine of six bird species. It turned out that there was no uric acid in it at all! Instead, ammonium, magnesium, and phosphate compounds were found.

The discovery challenges a long-held theory about how birds process nitrogenous waste. Scientists speculate that the uric acid is somehow altered before it is excreted, but the mechanism behind this transformation remains a mystery.

Beyond the unexpected chemical composition, bird poop is incredibly valuable to science. For example, Reddy’s lab uses the droppings of endangered plovers to collect DNA. This helps study their diet, microbiome, and even diseases without having to capture the birds.

So next time you get "luck," remember: it's not just poop, it's a scientific object full of evolutionary mysteries. What surprised you more: that birds don't pee, or that bird poop still remains a mystery to scientists? Share your thoughts in the comments!