This realm is not barren and lifeless. For a number of species it is home. The ptarmigan and the rose finch, the cony and the bighorn, live in the heights the year round. Many migrating birds and animals use the region for a nursery and a summer resort. Here, early in the autumn, Nature produces her last berries. Here assemble birds from the lowlands, and flocks from the North stop to feed and frolic while migrating to the Southland. Here, too, along with peaks and moorlands, meadows and wild-flower gardens, are crags, plateaus, cañons, lakes, glaciers, and snow-fields. Countless small, clear streams originate in these island heights and from them start merrily down to the far-off seas. Singly and in clusters, with areas large and areas small, these sky islands are a feature of most of the National Parks. [Illustration: ABOVE THE TIMBER-LINE IN THE ROCKY MOUNTAIN NATIONAL PARK Long's Peak on extreme left] In the Rocky Mountain National Park a few flowers bloom on the highest peaks more than fourteen thousand feet above sea-level. They are visited by numerous winged insects, even by butterflies. Let a cloud come over the sun, or a breeze start, and the butterflies, and perhaps other winged insects above timber-line, fold wings and drop and remain motionless till the sky clears. Evidently this is "safety first" from the short-lived but violent gales. It is believed that the Arctic-alpine plants in these heights were brought to them from the Arctic region on the great ice flow. They bloom in both these zones at about the same date. Among the bright blossoms in the polar mountain-top gardens are the columbine, gentian, aster, daisy, shooting-star, bluebell, a few kinds of phlox, and that dearest of the heath blossoms, the cassiope. Numbers are dwarfed to unbelievable smallness. Think of bluebells perfectly formed and colored and yet so fascinatingly small and dainty that a half-dozen could be sheltered in the upper half of a thimble! The alpine wild-flower garden on Mount Rainier is one of the most striking on the globe. Just above the timber-line and below and among the glaciers, colored flowers grow in tall and crowded luxuriance. They color broken distances for miles. It is doubtful if the world can show another hanging garden in which wild flowers so splendidly mingle their lovely hues with the broken picturesque forests, wild crags, and the grandeur of glaciers. In the Rocky Mountain National Park there is an accessible empire in the mountainous sky, up more than two miles above the wide plains of the sea. Mountain-climbers pass through these scenes on their way up peaks into the sky without stopping to see the wonders. They have at best only an introduction, or a hurried traveler's impression, of a strange and varied exhibit.