Hoopoes' eggs show their true colors

Date:

August 14, 2014

Source:

Springer Science+Business Media

Summary:

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 the eggs gradually change color when they are incubated, from bluish-grey to a more saturated greenish-brown. This happens because secretion from the uropygial or preen gland – a substance birds use to preen and protect their feathers – is transfered from the female hoopoe’s gland to her eggs directly with the bill and by means of belly feathers.

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