Long ago, shopkeepers in Southern California resorted to violence to drive out their pesky neighbors—the Cliff Swallows. The owners became so aggravated by swallows nesting on their buildings that they destroyed their mud homes. The displaced birds found refuge at the Mission San Juan Capistrano, where they built new nests in the eaves of the ancient stone church. Ever since, the birds have returned on March 19, St. Joseph’s Day, to raise their young within the safety of the mission walls; then, on October 23, San Juan’s Day, they leave for their wintering grounds in Argentina, circling once to bid the haven goodbye. Or so the legend goes. In reality, the birds do start arriving in the area in March, if not miraculously all on a single day. Since the early 1930s the people in the city of Capistrano have held a festival on the 19th to celebrate their return. Today, the event, which features ringing of the mission’s historic bells, Flamenco dance performances, food, and more...