You just finished washing your shiny red car and got hit with a flying white deuce. Happens to the best of us. People with white cars have much better odds that this problem will not ruin their day, windshields excluded. Why does bird poop have to be white when no other poop seems to be?
First off, bird poop is not completely white, part of it is white. And it could technichally be any color, depending on the bird’s diet. But, yes, bird poop is mostly and usually white…
Birds defecate differently than mammals. They have one multi-purpose hole called the cloaca that releases both feces, and what we would consider urine for mammals, although birds do not technically urinate.
Instead of urinating, a birds kidneys extract nitrogenous waste from the bloodstream. Most mammals extract the waste as urea dissolved in urine, but birds extract it in the form of uric acid. Uric acid, which is not very soluble in water, comes out pasty and white.
The white paste is released with the rest of the feces through the cloaca. Throw it all together and you have one nice piece of flying bird poop.
If you are hit don’t be discouraged, many people consider this a sign of good luck and good fortune to come.