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 scarcely suitable nesting sites more efficiently. Nevertheless it is not difficult to see two of them fight to contend a partner or some food, and it is precisely on these occasions that they "swell" to look bigger!
Phoenicopterus Ruber