This is a photo of Flamingos or flamingoes, some gregarious wading birds in the genus Phoenicopterus, the only genus in the family Phoenicopteridae.
Flamingos often stand on one leg, the other tucked beneath the body. The reason for this behavior is not fully understood. Some suggest that the flamingo, like some other animals, has the ability to have half of its body go into a state of sleep, and when one side is rested, the flamingo will swap legs and then let the other half sleep, but this has not been proven. Recent research has indicated that standing on one leg may allow the birds to conserve more body heat, given that they spend a significant amount of time wading in cold water. As well as standing in the water, flamingos may stamp their webbed feet in the mud to stir up food from the bottom.