We’ve all seen it, and possibly cursed it, on finding it on our car windshields or fresh laundry hanging out to dry in a backyard. White bird poop is a common sight, splattered on sidewalks, around bird feeders, and under branches popular with flocks of pigeons or starlings.
But have you ever stopped to wonder what makes bird poop white? Well, keep reading as we investigate the science behind those splatters.
Unlike mammals, birds do not produce urine as a separate bodily fluid. Instead, their bodily waste products are excreted together in the form of uric acid, a sticky white paste-like substance, with a darker, semi-solid interior.
Strictly speaking, bird poop itself is not white – it is in fact the urine element of a bird’s waste that gives it this distinctive color. Birds do not have a bladder that functions in the same way as a mammal’s does, and are adapted to make themselves as light as possible to enable the maximum flight efficiency at all times.
By eliminating urinary and fecal waste at the same time, birds are not constantly carrying around excess weight by storing urine in liquid form.
To find out more about the pooping habits of birds, and what influences the color of a bird’s droppings, keep reading. We also take a look at the superstitious belief that being pooped on by a bird is a sure sign of good luck on the horizon, and whether bird poop carries any serious health risks.
Close up of a Little Tern pooping on the beach
A bird’s kidneys work hard to extract nitrogenous waste from their body’s bloodstream. In humans and mammals, this waste product (urea) is dissolved and passes out of the body in the form of urine.
As birds do not have separate organs for urinating and defecating, all waste is excreted through one single opening called a cloaca. The cloaca serves as an entrance for reproductive purposes, for laying eggs, and as an exit point for excretion of bodily waste. The white sticky paste pooped by birds is uric acid, the equivalent of pee for birds.
Bird droppings are also sometimes known as guano, and contain a high concentration of nitrates and ammonia. By eliminating waste products in this paste-like form, birds limit the amount of water they lose, meaning that there is less risk of dehydration as they retain the water they need to stay healthy.
Close up of a bird poo
The droppings of all bird species will contain some extent of the white uric acid component, but the rest of the feces may also be colored according to the bird’s diet.
For example, birds that eat a lot of berries will excrete purple or reddish poop. Seed-eating birds’ droppings are more likely to be darker in color, as their diet contains food rich in pigments. Poop from birds that are mainly insectivores is lighter in color.
The poop produced by fish-eating birds like bald eagles or ospreys is whiter than that of many other species with carnivorous diets.
Fish are easier for birds to digest than small mammals or reptiles and other prey items with fur or exoskeletons that form the diet of carnivorous birds of prey.
So when an eagle digests a fish, there is less food waste to eliminate, which is what constitutes the darker element of a bird’s droppings.
Juvenile Golden Eagle pooping whilst perched on a tree branch
Bird poop carries more than 60 different diseases, the majority of which are connected to parasitic infections, including ringworm, chicken mites and bed bugs.
Serious health conditions linked to exposure to bird poop include the respiratory disease histoplasmosis, which develops from a naturally occurring fungus in birds’ feces.
Other risks linked to contact with bird droppings include salmonella, yeast infections (Candidiasis and Cryptococcosis), which can attack the respiratory, nervous, and pulmonary systems, and St. Louis encephalitis, which can cause potentially fatal inflammation of the nervous system.
Complications are incredibly rare and the majority of people will not develop any health issues when exposed to bird poop, but for those with compromised immune systems, excessive or prolonged contact with bird poop can carry the risk of serious illness.
Short-eared Owl pooing from a post
Although it may feel like the exact opposite when a bird poops on your freshly ironed jacket or immaculately styled hair, according to superstition, a bird pooping on you is the ultimate portent of good luck.
The superstition is said to have originated in Russia, where many people believe that the chances of getting pooped on are so low that it must mean that good fortune lies ahead. If a bird poops on your head, then you are truly blessed.
According to tradition, some sailors never clean bird poop from their vessels, believing that the mess will protect them at sea and bring them luck if they face a storm out on the waves.
There is one common exception, however. If the avian pooper is in fact a rook, then this is not considered lucky at all, in fact, quite the opposite. Some believe that being pooped on by a rook carries the symbolism of punishment for a previous bad deed.
Superstition says that having a bird poop on you is good luck
If you get bird poop in your eye, it may cause discomfort and itching, and it’s recommended to rinse it with clean water as soon as you can. Health risks from contact with bird poop are very rare but can have serious consequences. It’s important to seek medical advice if you are concerned.
Cases have been documented where patients who live or work in close proximity to bird roosts contracted cryptococcal meningitis, a potentially fatal swelling of the membranes around the brain, caused by fungal spores in bird droppings, especially those of pigeons.
The disease can cause vision disorders, including partial or total loss of sight in some cases. It’s incredibly rare, but can happen when exposure to a high concentration of feces occurs over a prolonged period.
Bird poop is acidic, and may cause irritation to your skin if left unwashed for a long period of time, but it is highly unlikely to burn you. The best advice is to wash it off as soon as you can, and the chances are you will not encounter any long-term effects or discomfort.
Brighten up your inbox with our exclusive newsletter, enjoyed by thousands of people from around the world.