Lucía loves to watch the monarchs' migration from her home in Mexico with Papá. But this year, the monarchs' journey north holds extra weight; Papá is heading north, too, to look for work. He promises her that when "the weather turns cold and the monarcas return, our winged ancestors will guide me home." So while he spends the summer months harvesting produce on faraway farms, Lucía watches the skies for signs of the monarchs'--and her Papá's--return. A...