Birds of the Rockies

by Leander S. Keyser

There is almost endless variety in the avi-faunal life of the Rockies. Some species breed far above timber-line in the thickets that invade the open valleys, or clamber far up the steep mountain sides. Others ascend still higher, building their nests on the bald summits of the loftiest peaks at an altitude of fourteen thousand feet and more, living all summer long in an atmosphere that is as rare as it is refreshing and pure. Among these alpine dwellers may be mentioned the brown-capped leucostictes, which shall be accorded the attention they deserve in another chapter. Then, there are species which have representatives both on the plains and far up in the mountain parks and valleys, such as the western robin, the western meadow-lark, and the mountain bluebird.

In this wonderful country there is to be observed every style of migratory habit. A twofold migrating current must be noticed. While there is a movement up and down the mountain heights, there is at the same time a movement north and south, making the migratory system a perfect network of lines of travel. Some species summer in the mountains and winter on the plains; others summer in the mountains pass down to the plains in the autumn, then wing their way farther south into New Mexico, Mexico, Central America, and even South America, where they spend the winter, reversing this order on their return to the north in the spring; others simply pass through this region in their vernal and autumnal pilgrimages, stopping for a short time, but spending neither the summer nor the winter in this latitude; still others come down from the remote north on the approach of autumn, and winter in this State, either on the plains or in the sheltering ravines and forests of the mountains, and then return to the north in the spring; and, lastly, there are species that remain here all the year round, some of them in the mountains, others on the plains, and others again in both localities. A number of hardy birds—genuine feathered Norsemen—brave the arctic winters of the upper mountain regions, fairly revelling in the swirling snow-storms, and it must be a terrific gale indeed that will drive them down from their favorite habitats toward the plains.

Does the avi-fauna of the Rocky Mountain district differ widely from that of the Eastern States? The reply must be made in the affirmative. Therefore the first work of the bird-student from the East will be that of a tyro—the identification of species. For this purpose he must have frequent recourse to the useful manuals of Coues and Ridgway, and to the invaluable brochure of Professor Wells W. Cooke on the "Birds of Colorado." In passing, it may be said that the last-named gentleman might almost be called the Colorado Audubon or Wilson.

In studying the birds of the West, one should note that there are western subspecies and varieties, which differ in some respects, though not materially, from their eastern cousins; for instance, the western robin, the western chipping sparrow, the western lark sparrow, and the western nighthawk. Besides, intermediate forms are to be met with and classified, the eastern types shading off in a very interesting process into the western. It would be impossible for any one but a systematist with the birds in hand to determine where the intermediate forms become either typical easterners or typical westerners.

Most interesting of all to the rambler on avian lore intent is the fact that there are many species and genera that are peculiar to the West, and therefore new to him, keeping him constantly on the qui vive. In Colorado you will look in vain for the common blue jay, so abundant in all parts of the East; but you will be more than compensated by the presence of seven other species of the jay household. The woodpeckers of the West (with one exception) are different from those of the East, and so are the flycatchers, the grosbeaks, the orioles, the tanagers, the humming-birds, and many of the sparrows. Instead of the purple and bronzed grackles (the latter are sometimes seen on the plains of Colorado, but are not common), the Rockies boast of Brewer's blackbird, whose habits are not as prosaic as his name would indicate. "Jim Crow" shuns the mountains for reasons satisfactory to himself; not so the magpie, the raven, and that mischief-maker, Clark's nutcracker. All of which keeps the bird-lover from the East in an ecstasy of surprises until he has become accustomed to his changed environment.

One cannot help falling into the speculative mood in view of the sharp contrasts between the birds of the East and those of the West. Why does the hardy and almost ubiquitous blue jay studiously avoid the western plains and mountains? Why do not the magpie and the long-crested jay come east? What is there that prevents the indigo-bird from taking up residence in Colorado, where his pretty western cousin, the lazuli finch, finds himself so much at home? Why is the yellow-shafted flicker of the East replaced in the West by the red-shafted flicker? These questions are more easily asked than answered. From the writer's present home in eastern Kansas it is only six hundred miles to the foot of the Rockies; yet the avi-fauna of eastern Kansas is much more like that of the Eastern and New England States than that of the Colorado region.

Perhaps the reason is largely, if not chiefly, physiological. Evidently there are birds that flourish best in a rare, dry atmosphere, while others naturally thrive in an atmosphere that is denser and more humid. The same is true of people. Many persons find the climate of Colorado especially adapted to their needs; indeed, to certain classes of invalids it is a veritable sanitarium. Others soon learn that it is detrimental to their health. Mayhap the same laws obtain in the bird realm.

The altitude of my home is eight hundred and eighty feet above sea-level; that of Denver, Colorado, six thousand one hundred and sixty, making a difference of over five thousand feet, which may account for the absence of many eastern avian forms in the more elevated districts. Some day the dissector of birds may find a real difference in the physiological structure of the eastern and western meadow-larks. If so, it is to be hoped he will at once publish his discoveries for the satisfaction of all lovers of birds.

If one had time and opportunity, some intensely interesting experiments might be tried. Suppose an eastern blue jay should be carried to the top of Pike's Peak, or Gray's, and then set free, how would he fare? Would the muscles and tendons of his wings have sufficient strength to bear him up in the rarefied atmosphere? One may easily imagine that he would go wabbling helplessly over the granite boulders, unable to lift himself more than a few feet in the air, while the pipit and the leucosticte, inured to the heights, would mount up to the sky and shout "Ha! ha!" in good-natured raillery at the blue tenderfoot. And would the feathered visitor feel a constriction in his chest and be compelled to gasp for breath, as the human tourists invariably do? It is even doubtful whether any eastern bird would be able to survive the changed meteorological conditions, Nature having designed him for a different environment.