Flamingo's are a type of wading bird, and surprisingly, they have a remarkable relationship with grebes! They hold at least eleven morphological traits in common, which are not found on other birds.
Flamingo's will often stand on only one leg, this is believed to allow them to conserve more body heat, but it is not fully understood. The way their beaks are helps them to separate mud and slit from the food they eat and unlike other birds, they are used uniquely upside down!
The filtering of food items is assisted by hairy structures called lamellae which line the mandibles, and the large rough-surfaced tongue. The pink or reddish color of flamingos comes from carotenoid proteins in their diet of animal and plant plankton.
Flamingos whose sole diet is blue-green algae are darker in color compared to those who get it second hand (e.g. from animals that have digested blue-green algae)
Flamingos are very social birds; they live in colonies whose population can number in the thousands. These large colonies are believed to serve three purposes for the flamingos: avoiding predators, maximizing food intake, and using scarce suitable nesting sites more efficiently.
Flamingos form strong pair bonds of one male and one female, although in larger colonies flamingos sometimes change mates, presumably because there are more mates to choose from).
The greater flamingo is the tallest flamingo, standing 110 to 130 cm (43-51 in.) and weighing up to 3.5 kg (7.7 lb.).
The lesser flamingo is the smallest flamingo, standing 80 cm (31.5 in.) and weighing only 2.5 kg (5.5 lb.).
The wingspan of flamingos ranges from 95 to 100 cm (37-39 in.) for the lesser flamingo to 140 to 165 cm (55-65 in.) for the greater flamingo. The Caribbean flamingo has a wingspan of 150 cm (59 in.).
(Some Info Sited From [link]