Why Bird Poop Is White

Birds brighten our lives. They connect us with nature. But sometimes they connect us a bit too directly with nature. Park under the wrong tree - where a flock of starlings or grackles comes to roost - and nature may cover your car so thickly that it takes a trip or two through the carwash just to see through the windshield again. And why is most of the bird poop we see white? The answer is that birds, unlike mammals, don't produce urine. Instead they excrete nitrogenous wastes -- ammonium urate, struvite and two unknown compounds -- which emerge as a white paste. Owners of red cars, look out! A study in England found that red cars are most likely to be the target of bird droppings!

BirdNote^®

Why Is Bird Poop White?

Written by Bob Sundstrom

This is BirdNote.
[Black-headed Grosbeak song]
Birds brighten our lives. [Continue Black-headed Grosbeak song] We find joy in their songs, inspiration in their soaring flight. They connect us with nature.
But sometimes birds connect us a bit too directly with nature.
[Boink!!]
Park under the wrong tree – one where a flock of starlings or grackles comes to roost – and nature may be painted in white on your car so thickly that it takes a trip or two through the carwash just to see through the windshield again.
[Flock of European Starlings]
This messy encounter raises some questions: Why is most bird poop white? And why is it so hard to get off your car?
Bird droppings are often called “whitewash.” Molecular products concentrated by a bird’s kidneys emerge as a white substance. Recently, whitewash was shown to be made up of ammonium urate, struvite and two unknown compounds -- but not uric acid, as was long thought.
It appears that drivers of some cars might be asking for trouble. A study in England found that red cars are most likely to be the target of bird droppings, followed by blue and black. Green was the least likely. So be careful where you park. And give that red Mustang a wide berth.
For BirdNote, I’m Michael Stein.
[Black-headed Grosbeak song]
###

Bird sounds provided by The Macaulay Library at the Cornell Lab of Ornithology, Ithaca, New York. Grosbeak recorded by T.G. Sander.
Flock of European Starlings recorded by Martyn Stewart of naturesound.org.
Producer: John Kessler
Executive Producer: Chris Peterson
© 2014 Tune In to Nature.org November 2017/2019 Narrator: Michael Stein
ID# poop-02-2012-11-26 poop-02c

References

https://link.springer.com/article/10.1007/s10336-019-01692-5

Birds “targeting” red vehicles: http://www.wtop.com/681/2916790/Even-birds-have-favorite-car-colors----…