Subclass Neoaves. Order Phoenicopteriformes (Flamingos. From the greek 'phoinix'=crimson, and 'pteron'=wing). Long-legged, generally pink birds, with long necks and down-turned bills. Tropical birds that feed in shallow water on invertebrates. They develop their pink colour by sequestering the pigments from crustacean prey. The Greater Flamingo, pictured here, is the only species occuring naturally in the United States.