The Incredibly Colorful And Unique Eggs Of Common Murres·
On narrow shelves cut into steep rocky cliffs in northern parts of the world, vast colonies of common murres, tens of thousands strong, lay their uncommon eggs. The birds are highly adapted to their precarious existence: their eggs are conical so they roll in circles, rather than off a ledge and into the sea. The eggs also come in colors from deep blue to pale beige, with a seemingly infinite range of patterns of ruddy-to-blackish speckles. Laid on bare rock—so close together that a brooding parent might touch the one beside it—each egg’s unique look allows mother (and possibly father) murres to identify it as their own progeny.
Establishing these details has been the work of Mark Hauber, an animal behavior researcher at the University of Illinois at Urbana-Champaign. Building on previous work, Hauber’s latest additions to the field are two revelations: year after year a female murre will produce an egg with a shell pattern that has an individualized, recognizable pattern that is nearly identical to her previous eggs, by manipulating just two pigments, biliverdin and protoporphyrin IX. And this ability is genetic.
Photo: Dick Daniels/Wikimedia Commons
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