Thousands of years ago in a land far away, plate tectonics created a mountain range that separates a population of red parrots. on the east side of the mountain, the recessive trait of blue feathers was selected for because it the parrots avoid predators. however; on the west side of the mountain the parrots kept the trait of red feathers. one day, to escape a storm, a small number of blue parrots migrated to the west side of the mountain where the red parrots dwell. identify and explain the evolutionary mechanism at work in this scenario, then predict how the populations of parrots will be affected by the migration.