The Rosario butterfly reserve in Mexico is filled with the murmur of fluttering butterfly wings; branches of the trees are bowed down with thousands of the creatures. This is where the Monarch butterflies land after their 3,000-mile journey across America. The Monarch is the only creature to migrate like birds. It flies north to south at altitudes of 3,000 feet, dodging aeroplanes and predators. But, unlike birds, the Monarch never makes the full loop so it will never have been to the sunny pine forest where it ends up. But every butterfly has an innate sense of its route. Scientists have been tracking this enigmatic creature and its journey for years: its wintering site in Mexico was only discovered twenty years ago, after a search of twenty-three. Four Wings and a Prayer tells of the quest to trace the Monarch migration. It began in 1952 when two entomologists and 4,000 volunteers tagged hundreds of butterflies. Halpern weaves the stories of these volunteers into her narrative - men and women who for no other reason but a fascination with the strangely beautiful creatures, joined the project, becoming swept up by the idea of understanding their journey. One, a secretary, gave up her job when a Monarch landed on her desk, and became grand marshall of a butterfly parade. Another lives out of his truck for three months when the butterflies pass through his state in order to follow them. This elegantly written book combines these personal stories with a scientific examination of the Monarch, and its extraordinary journey across a continent.