Eggshells look more colorful through birds' eyes

http://www.msnbc.msn.com/id/38831832/ns/technology_and_science-science/

By Wynne Parry
updated 1 hour 34 minutes ago

Birds see a more colorful world than we do, especially when it comes to their eggs, a new study suggests.

Unlike humans, birds can see ultraviolet (UV) light, and they have four rather than three color receptors in their eyes, allowing them to better distinguish between hues.

Now researchers have shown that while most of the color variation in eggshells can be seen by humans and birds alike, a swath of hues that our eyes miss may play an important role in avian life. For instance, we are oblivious to the UV pigment that may help birds differentiated between their own eggs and those of another species.

Among vertebrates, birds are unique in laying eggs with pigmented shells, though scientists suspect the ancestral egg was white and had none of the speckles now common on birds' eggs.

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