Veteran birders will know how to use this book. Beginners, however, should spend some time becoming familiar in a general way with the illustrations. They are not arranged in systematic or phylogenetic order as in most ornithological works but are grouped in 8 main visual categories:
(1) Swimmers — Ducks and ducklike birds (2) Aerialists — Gulls and gull-like birds (3) Long-legged Waders — Herons, cranes, etc.
(4) Smaller Waders — Plovers, sandpipers, etc.
(5) Fowl-like Birds — Grouse, quail, etc.
(6) Birds of Prey — Hawks, eagles, owls (7) Nonpasserine Land Birds (8) Passerine (Perching) Birds
Within these groupings it will be seen that ducks do not resemble loons; gulls are readily distinguishable from terns. The needlelike bills of warblers immediately differentiate them from the seed-cracking bills of sparrows. Birds that could be confused are grouped together when possible and are arranged in identical profile for direct comparison. The arrows point to outstanding “field marks” which are explained opposite.