The Flamingo species live in the freezing artic. The Flamingos are eaten by hungry killer whales that saw them from down below
More juvenile Flamingos are born than can survive on the glacier. There is not enough food or space for all of them to live. Some of the Flamingos are always spotted by the whales and eaten.
Not all the Flamingos are pink. Some Flamingos are born with other colors. All of the Flamingos on the glacier are competing to stay hidden from the whales and not get eaten.
The brightly colored flamingos really stand out against the white, cold ice. That makes them easy to see. The white flamingos match the color of the environment, making it easier for them to hide.
Because their color is an adaption on the glacier, white flamingos are better at avoiding whales. White flamingos are eaten less often and survive longer.
Only surviving flamingos get a chance to reproduce. Because most of those flamingos are white, they pass on the white color trait to their offspring. Therefore, a greater percentage of flamingos are white in the next generation.