They sail in on wingspans of 7 feet, arriving in groups of three and four. The massive birds stake out their roosts for the night, and they jostle, cry and call.
As the sun sets, the assembly swells into the thousands. The birds' wild, rolling cries fill the sky. Visitors look on from just a few yards away.
It's like something out of an African safari. But this scene – one of the planet's great natural spectacles – is in the Chihuahuan Desert.
Bosque del Apache National Wildlife Refuge, on the Rio Grande near Socorro, New Mexico, was created as a sanctuary for migrating waterfowl. Each winter, it's home to as many as 15,000 greater sandhill cranes, tens of thousands of geese and...