How can you tell a male flamingos from a female?

No, you can't. Some animals look different, and some don't. They look the same. The only way to tell between a female flamingo, and male flamingo is by... I f you happen to see a flamingo sitting on a nest, or sitting on its egg, then that is a female flamingo. Maybe male flamingos have black marks, and others with no black marks might be hopefully be females.