On my first morning in the Mexican state of Yucatán, in a nearly deserted wilderness area, a ruby-throated hummingbird dashed toward me, flitted away, then dove back for a second encounter. Likely he wanted to mark his chosen territory, a patch of riotous shrubs braced against the pull of the coastal winds that scour the northern edge of the Yucatán peninsula. The hummingbird had made its winter home here, where white sand dunes featured a dense weave of mangrove, wax mallow, geiger tree, seagrape, bay cedar and lily.