Yellowstone National Park
311 species of birds have been found. Almost half of them nest in Yellowstone. As of 1999, twenty-six pairs of nesting bald eagles have been counted. Very rarely, whooping cranes have been seen; only three are known to live in the Rocky Mountains, out of 385 known worldwide. Other birds, which are at risk because they are rare in Yellowstone, include the common loon, harlequin duck, osprey, peregrine falcon and the trumpeter swan.