Today I learned why bird poop is usually white vs. other animal and human poop. Birds do not urinate. While their kidneys extract nitrogenous waste it is not expelled in the urea as ours (and many other animals) does. It is excreted in the form of uric acid, which has low solubility and, when combined with other waste comes out like white paste. Other colors from various fruits, etc., do not change as they pass through the system, so they come out the color of the fruit ingested. Some vegans seem to pass green due to the excess green vegetables and iron in the body.
In order to fly efficiently, birds, especially smaller birds need to
eliminate waste often. A budgie may excrete 40 to 50 times in a day,
whereas a macaw may only go 15 or 20 times.”
Since birds only have one opening, it is used for sex, waste
elimination, and dropping eggs.
The word poop comes from the Middle English word poupen or or latin
puppis, and it originally meant fart it acquired its current meaning