Nature: Turning Colors

In my country if something has a high value and is rare we say that this thing is like a "white raven", so what if thanks to human's greedy nature and actions like deforestation small things like ravens will become so rare that they will become like "white raven"? In my building, we can see one of the few ravens that are still alive. He is sitting on the last tree from the great forest which is now consumed by the flames. Like you can see he already started changing colors before the fire, but what will happened when the last tree will burn down? Will he become a "white raven"?