There once was two hawks that lived a good easy life eating small snakes but something bad happened.
It rained very hard one night while the hawks were eating their snake and the storm was very bad and made most of the snakes die out.
The hawks had a hard time finding food, and soon winter came and made it even harder for the hawks to survive so the hawks decided to migrate south to find a warmer place to live.
The hawks found a place similar to their old home but it didn't have snakes. They easily adapted to the new place but had a little trouble catching food.
There were black and white rats, and the hawks mostly ate black rats so that soon created a population loss for black rats. The hawks had a offspring that could catch rats easier which the offspring was smaller and faster.
Since black rats were being eaten by the hawks the white rats could reproduce more and have more babies, soon there was a lot more white rats then black rats. Then once the black rats were almost extinct the hawks adapted to eating white rats. The End.