Most people are all too familiar with the white sludge that can fall from above as you enjoy the outdoors, universally recognized as bird poop. Yet we don’t experience a similar threat, as far as we know, in the form of a liquid bird urine.
The answer to this question depends on how you define peeing. Basically, no, you don’t need to worry about a pale yellow liquid urine sprinkling you when birds fly above, because birds don’t release that kind of urine.
Do birds produce urine?
Birds do produce urine, but it has different components than mammalian urine has. Birds, like mammals, have kidneys that filter the blood and manage water and salt balance, sending waste away to be excreted from the body.
In birds, the nitrogenous waste from amino acid metabolism is made instead into uric acid. This is excreted in a product that serves the same purpose as urea-based urine, but its different components make it look different as well. Bird urine is a white liquid suspension full of uric acid crystals.
How do birds release urine from the body?
Birds do not release urine from the body through an opening at the end of a urethra. Once the urine passes through the ureters to reach the cloacal chambers, the urine and feces mix together and leave the bird’s body through the cloacal opening.
Thus, the white sludge that is commonly called bird poop is actually a mix of bird urine and feces and, in fact, often has visible dark solids.