“Migration can be triggered by the angle of sunlight, indicating a change in the season, temperature, plant life, and food supply. Female monarchs lay eggs along the route. Every history has more than one thread, each thread a story of division. The journey takes four thousand eight hundred and thirty miles, more than the length of this country. The monarchs that fly south will not make it back north. Each departure, then, is final. Only their children return; only the future revisits the past.”