This is why they have made the journey after the famine of winter. Food is everywhere. Birds have flown in from as far away as the Arctic and subtropics. Canada geese join in flocks of white pelicans to breed here. 

 

A snow-covered wasteland is transformed to an American Serengeti. But it's a landscape like no other. Geysers made Yellowstone famous. Yellowstone sets above the molten core of a volcano. Underground water become super-heated and erupts into the air. Strangely, geysers and hot springs can creep around the landscape. The curious shapes of grotto geyser are actually trees entombed and petrified by minerals dissolved in the water.