The author embarks on an extensive exploration of the bird life in the Rocky Mountains, traveling from the arid plains to the alpine summits of Pike's Peak and Gray's Peak. The narrative highlights the vertical migration of birds, explaining how altitude serves the same purpose for mountain-dwelling species as high latitude does for eastern birds. The text contrasts eastern and western avian forms, examining why certain species thrive in the dry, rarefied atmosphere while others avoid it.
Detailed observations bring readers face to face with unique western species, such as the mountain bluebird, the water-ousel, the magpie, and the long-crested jay. The author meticulously describes their songs, nesting habits, and adaptations to the harsh mountain environment. The book provides a careful study of comparative ornithology, analyzing differences between eastern and western subspecies like meadow-larks and towhees.
Throughout the journey, the author explores the rich ecosystems of mountain lakes, deep cañons, and high green valleys. Specific attention is given to the vocalizations of various thrushes, warblers, and sparrows, capturing the auditory experience of the mountain wilderness. The narrative also includes encounters with rare species like Williamson's sapsucker and the brown-capped leucosticte.
The work culminates in a challenging ascent of Gray's Peak, illustrating the perseverance required to study alpine birds in their natural element. The journey blends scientific observation with a deep appreciation for the natural beauty of the Rockies. It closes with a reflection on the harmonious relationship between the mountain birds and their rugged surroundings.
