Print
Ask an expert
14 September 2007
Why is bird poo white?
Sent in by John Martin Lamberty, near Lewes, East Sussex
Ian Hayward, Wildlife Adviser
Ian answers...
Firstly, it is not actually the bird poo that is white, it is uric acid which is the bird equivalent to humans urine. Without going into too much technical detail, it is white due to the chemical reactions that occur within the urinary system to process the waste matter into a substance that can be safely excreted with minimal water loss.
Birds excrete waste products from the urinary and digestive tract at the same time through what is known as the vent after passing through an organ known as the cloaca. Because they are expelled at the same time but from different systems, they do not have time to mix which explains why bird mess usually consists of distinct coloured and white parts.
However, certain foods such as elderberries may alter the colour of birds excretia as the colour of the fruit persists throughout the digestive process.
About Ian
I've been working at the RSPB as a wildlife adviser since October 2005. I have been a keen naturalist all of my life with a particular interest in birds, insects and animal behaviour. I have a background in Environmental Biology and Environmental Impact Assessment and regularly contribute to bird surveys. Other interests I have include wildlife gardening and birding as well as keeping track with important issues such as climate change and renewable energy.
Do you have a question for our experts?
Each week we answer one question sent in by our visitors about birds or wildlife. I have a question