Dawn with the Sandhill Cranes

Each winter, some 12,000 sandhill cranes descend on New Mexico's Rio Grande valley, arriving from as far as Siberia and Alaska to winter at Bosque del Apache National Wildlife Refuge. November through February is their season, and dawn is the moment to be there. Thousands lift off the marshes at once, bugling, the pale sky briefly full of wings, then spiral back at dusk to roost in the shallows. For the spring half of the story, Rowe Sanctuary on Nebraska's Platte River gathers half a million cranes each March, the largest congregation on Earth.