Friday was Day 26 of the Papa’s Walk Challenge. As I walked through the neighborhood, I kept seeing splotches of bird poop all over the sidewalks and streets directly beneath trees and utility wires. I began to wonder why bird poop is white. When I got home, I looked it up on the Net and discovered that the white excrement is uric acid, which is essentially equivalent to a mammal’s urine.
AllAboutBirds.com, gave a rather ho-hum explanation: “Mammals excrete waste as urea dissolved in urine, birds excrete it as uric acid, which has a low solubility in water, so it comes out as a white paste.”
An article by Matt Soniak on MentalFloss.com, had a much more descriptive and fascinating explanation. Birds have only one opening (called a cloaca) located beneath their tail that is used for excretion, urination, and reproduction. According to the article, “This orificial multitasking explains the dark bullseye that’s often in the center of the white acid waste. That’s the actual “poop” part, or stool. Because the acid and poop are expelled at the same time from the same opening, but from two different bodily systems, they don’t have much time to blend, and you get a bird dropping with two distinct parts that looks like a poor man’s Rorschach test.” Click here to learn more.