Thursday, May 17, 2012

The Blue-Footed Booby Has Multipurpose Feet

Sula nebouxii - 06
Photo Credit: Maros (via Wikimedia Commons)
The Blue-Footed Booby is a bird with feet that are made for more than just walking. Like most seabirds, his feet are webbed and work as paddles for swimming and diving. On the downside, the web shape makes the bird clumsy as he walks on land, which is where his funny name came from ("booby" comes from the Spanish word "bobo," which means "stupid" or "clown"). Even so, the male blue-footed booby is quite proud of his feet, and he uses them to help attract a mate.

As one may guess from this bird's name, the feet are often blue in color. However, the color actually ranges from bright green to dull blue. When the male is ready to attract a female, he will perform a courtship dance full of struts and high steps - all moves meant to show off his feet. Studies have shown that females tend to prefer bright green, and that the color is dependent on the amount of carotenoids in the diet. Therefore, it seems the color is an indicator of the booby's nutritional condition (and suitability as a mate). 

The blue-footed booby has one more important use for those feet. These birds do not have brood patches (a bare patch of skin on the bird's belly for sitting on the eggs), so they use their feet to keep the eggs warm. The parents will continue using their feet to keep the babies warm even after hatching, as the chicks are unable to control their own temperatures for about the first month of life. 

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