# Why is bird poo white? **URL:** \ **Category:** Factual Questions\ **Created:** [June 16, 2002, 5:05am UTC](https://boards.straightdope.com/t/why-is-bird-poo-white/114316 "2002-06-16T05:05:56Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![fluoronaut](https://avatars.discourse-cdn.com/v4/letter/f/73ab20/32.png) [@fluoronaut](https://boards.straightdope.com/u/fluoronaut)\ **Post date:** [June 16, 2002, 5:05am UTC](https://boards.straightdope.com/t/why-is-bird-poo-white/114316/1 "2002-06-16T05:05:56Z")
I doubt I’m the first person to ask this, but a search of the archives has revealed nothing. Could someone enlighten me? Thanking you and grovelling in admiration, Alice ---
**Author:** ![Duckster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duckster/32/1244_2.png) [@Duckster](https://boards.straightdope.com/u/Duckster)\ **Post date:** [June 16, 2002, 5:21am UTC](https://boards.straightdope.com/t/why-is-bird-poo-white/114316/2 "2002-06-16T05:21:38Z")
It’s not poo. It’s urine. But if you look closely, the teeny, tiny dark speck in the middle is the poo. ---
**Author:** ![Darwins\_Finch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darwins_finch/32/20304_2.png) [@Darwins\_Finch](https://boards.straightdope.com/u/Darwins_Finch)\ **Post date:** [June 16, 2002, 5:27am UTC](https://boards.straightdope.com/t/why-is-bird-poo-white/114316/3 "2002-06-16T05:27:00Z")
Actually, the white part is composed of _urates_; bird urine tends to be clear and watery. ---
**Author:** ![TheeGrumpy](https://avatars.discourse-cdn.com/v4/letter/t/779978/32.png) [@TheeGrumpy](https://boards.straightdope.com/u/TheeGrumpy)\ **Post date:** [June 16, 2002, 5:56am UTC](https://boards.straightdope.com/t/why-is-bird-poo-white/114316/4 "2002-06-16T05:56:03Z")
The missing ingredient here is something rather obvious: a bird has an all-purpose butthole, or _cloaca_. It all comes out at once. ---
**Author:** ![ratty](https://avatars.discourse-cdn.com/v4/letter/r/ccd318/32.png) [@ratty](https://boards.straightdope.com/u/ratty)\ **Post date:** [June 16, 2002, 5:57am UTC](https://boards.straightdope.com/t/why-is-bird-poo-white/114316/5 "2002-06-16T05:57:57Z")
Birds and reptiles do not pee like we do- they excrete liquid waste in mainly crystalline form, called urates. They do not produce uric acid, which is the main component of human urine. This system is thought to have evolved as a way to control water loss, since the chalky urates contain far less water than human urine. But they do release some waste water- just not much. ---
**Author:** ![Darwins\_Finch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darwins_finch/32/20304_2.png) [@Darwins\_Finch](https://boards.straightdope.com/u/Darwins_Finch)\ **Post date:** [June 16, 2002, 6:04am UTC](https://boards.straightdope.com/t/why-is-bird-poo-white/114316/6 "2002-06-16T06:04:21Z")
Not only does it limit water loss, but it’s a major boon for egg layers. Urates are generally inert nitrgoenous wastes, whereas urine (as excreted by mammals) has a significant ammonia component; the buildup of ammonia within an enclosed egg would be fatal to the developing embryo. ---
**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\ **Post date:** [June 16, 2002, 6:22am UTC](https://boards.straightdope.com/t/why-is-bird-poo-white/114316/7 "2002-06-16T06:22:02Z")
Stay tuned to the [Straight Dope Home Page](http://www.straightdope.com). In the next week or two there should be a Staff Report by **Colibri** that addresses this very question.