Aflatoxin is a poisonous substance that is formed by mould (Aspergillus fungi) that can grow on seeds such as peanuts, sunflower hearts and walnuts. It's particularly prevalent in peanuts.
The mould forms Aflatoxin as a defence mechanism to out-compete other moulds and protect itself.
Aflatoxin is as the name suggests a toxin. It is harmful to garden birds and in rare cases can cause death.
It causes liver damage to birds and increases their risk of cancer.

