To study the birds from the level plains to the crests of the peaks swimming in cloudland; to note the species that are peculiar to the various altitudes, as well as those that range from the lower areas to the alpine heights; to observe the behavior of all the birds encountered in the West, and compare their habits, songs, and general deportment with those of correlated species and genera in the East; to learn as much as possible about the migratory movements up and down the mountains as the seasons wax and wane,—surely that would be an inspiring prospect to any student of the feathered fraternity. For many years one of the writer's most cherished desires has been to investigate the bird life of the Rocky Mountains. In the spring of 1899, and again in 1901, fortune smiled upon him in the most genial way, and—in a mental state akin to rapture, it must be confessed—he found himself rambling over the plains and mesas and through the deep cañons, and clambering up the dizzy heights, in search of winged rarities.
In this chapter attention will be called to a few general facts relative to bird life in the Rockies, leaving the details for subsequent recital. As might be expected, the towering elevations influence the movements of the feathered tenants of the district. There is here what might be called a vertical migration, aside from the usual pilgrimages north and south which are known to the more level portions of North America. The migratory journeys up and down the mountains occur with a regularity that amounts to a system; yet so far as regards these movements each species must be studied for itself, each having manners that are all its own.
In regions of a comparatively low altitude many birds, as is well known, hie to the far North to find the proper climatic conditions in which to rear their broods and spend their summer vacation, some of them going to the subarctic provinces and others beyond. How different among the sublime heights of the Rockies! Here they are required to make a journey of only a few miles, say from five to one hundred or slightly more, according to the locality selected, up the defiles and cañons or over the ridges, to find the conditions as to temperature, food, nesting sites, etc., that are precisely to their taste. The wind blowing down to their haunts from the snowy summits carries on its wings the same keenness and invigoration that they would find if they went to British America, where the breezes would descend from the regions of snow and ice beyond the Arctic Circle.
White-Crowned Sparrows
It will add a little spice of detail if we take a concrete case. There is the handsome and lyrical white-crowned sparrow; in my native State, Ohio, this bird is only a migrant, passing for the summer far up into Canada to court his mate and rear his family. Now remember that Colorado is in the same latitude as Ohio; but the Buckeye State, famous as it is for furnishing presidents, has no lofty elevations, and therefore no white-crowns as summer residents. However, Colorado may claim this distinction, as well as that of producing gold and silver, and furnishing some of the sublimest scenery on the earth; for on the side of Pike's Peak, in a green, well-watered valley just below timber-line, I was almost thrown into transports at finding the white-crowns, listening to their rhythmic choruses, and discovering their grass-lined nests by the side of the babbling mountain brook. Altitude accomplishes for these birds what latitude does for their brothers and sisters of eastern North America.