The Woodlands birds have overtime adapted with their environment as the trees darkened so did the color of their feathers so they could blend in
Adaptation
Adaptation is when a trait is inherited to help a species better fit in and adapt to their environment
Natural Selection is the survival of the fittest whoever can blend into their environment and be the strongest will survive
The darker brown woodland birds have the more favorable trait since they blend into the trees that they inhabit more therefore more off them will survive and pass down that gene to offspring.
Natural Selection
Since the darker brown woodland birds survive much better in the forest with dark wood they kept reproducing while the lighter birds slowly died off and within the last 1000 years there is a 2 million-957k ratio between light brown and dark brown woodland birds
Speciation
Speciation is where the adaptation that is favorable in environment will reproduce and continue on while the unfavorable species will eventually die off