Trumpeter swans, Yellowstone National Park. An adult leads 7 juveniles slowly down the Yellowstone River at sunrise, on a freezing morning. These may very well be the chicks of this adult (the other adult was near), as they usually lay 4-6 eggs, but it's hard to tell. These swans usually mate for life, forming their pair bond by as early as 3 years old, and can live in the wild to at least 26 years old. They're absolutely beautiful, and as our largest species of waterfowl when they open their 6-foot wingspan to stretch, it takes your breath away.