I am baffled by the process of evolution in which mutations occur constantly. For example lets imagine that a flock of birds manage to travel into an environment in which they wouldn't be suitable to survive in. Evolution states that the bird with the gene that is suitable for the environment is more likely to survive and pass their adaptable trait to their offspring opposed to the ones with out the trait. This process states that the mutation may take thousands of years to multiply along with other genetic mutations that makes the species more diverse, but lets say that these flock of birds settle into an environment that is too cold for them to survive. The flock of birds try to reproduce to stay alive. So I question whether or not they somehow keep reproducing for that extremely rare mutation for them to survive. Or if they can't manage to pass the create the adaptable gene for their offspring they are to render themselves into extinction. Or can environment somehow alter the gene for example skin pigmentation for them to become suitable.