The Migration of North American Birds (1935)

The work surveys historical observations and contemporary research on bird migration, explaining proposed causes and adaptive advantages, seasonal timing, species- and group-specific movement patterns, and differences between nocturnal and diurnal travel. It examines flight mechanics (speed, altitude, orientation), migration distances and routes—coastal, interior river-valley, oceanic, and Arctic pathways—migration lanes, vagrancy, and vertical movements; discusses hazards such as storms, aerial obstructions, and exhaustion; and describes data sources and methods including banding studies, concluding with implications for habitat management and species protection.