The two greater flamingos in the foreground here are males caught in an "I'm taller than you are" dominance display. The flock here is mostly lesser flamingos with a few greater flamingos mixed in (and a few other birds). This was taken in a small soda lake next to, but not connected to, the freshwater Lake Naivasha. These flamingos "commute" between the soda and freshwater lakes of the Rift Valley.
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