Preen gland secretion causes hoopoes’ eggs to change color, possibly giving signals about the robustness of the mother bird, researchers have found. Hoopoe females use cosmetics on their eggs - and ...

In preparation for birth, some expectant human parents will build IKEA cribs or down prenatal vitamins. Female hoopoes douse their eggs in a pungent postcoital goo. Shortly after laying their eggs, ...