If you are a curious person, you must have noticed on more than one occasion when observing wild birds or your birds that you have as pets, that despite spending most of the time eating and defecating, they never excrete fluids or rather, they never urinate like We do it or the rest of the animals.
This is because birds have a very unique and highly efficient excretory system, in which structures common to those of other living organisms can be found, such as the kidneys, those in charge of filtering and absorbing substances that are harmful and of waste for the body or also the ureters, responsible for transporting these wastes to the point of exit, among other organs. However, something makes this system very different from the one we have, birds do not have bladders, except for ostriches and rheas, therefore it is impossible for them to store urinary waste in liquid form.
How do birds pee?
Like any other animal, birds have to expel waste derived mainly from protein breakdown, waste that is toxic to the body. The most common way to eliminate these wastes is in the form of a substance called urea, which is soluble in water and needs large amounts of it to be diluted and to be excreted correctly.
However, both in birds and reptiles, what is produced is not this substance but rather uric acid, a compound that is almost insoluble in water and that is eliminated in the form of small crystals, with a pasty texture and very white color. This substance is eliminated along with the digestion waste, because the birds have a single exit hole called the cloaca, which is responsible for expelling the waste produced by digestion, as well as the semen and eggs.
So when a bird defecates, we can see that its waste has two colors, a dark part that is composed of digestive waste, such as the undigested parts of seeds, the cuticles of insects, among some others, and a white part. which is uric acid, in other words the almost solid urine of birds.