Since I don't have the details of the 'Mud City A Flamingo Story', it's hard to say for sure. However, generally speaking, it could be a story centered around a flamingo's experience in Mud City. It might include elements such as the flamingo's appearance in the city being a novelty, and how the city's ecosystem (with all its mud) affects the flamingo's behavior. It could also explore themes like adaptation, as the flamingo tries to adjust to the new and muddy surroundings.
I'm not sure specifically as I haven't read it. But it might be about a flamingo in a muddy city, perhaps its adventures or how it lives in that particular environment.