There are many excellent books to help identify animal tracks--and a few genuinely misleading ones. The books below are the ones that I turn to myself for reference. All of these books are written by highly skilled trackers and naturalists; include accurate, detailed illustrations for a wide range of species; and are loaded with well-researched information backed by many years if not decades of time in the field.
Casey McFarland and Mark Elbroch$49.95 $44.96
This book quickly became *the* go-to reference for mammal sign when it was first released in 2003. The new second edition is more comprehensive, more user friendly and is the gold standard for tracking guides. It is large to carry in the field. I use mine as a desk reference.
Wildlife of the Pacific Northwest: Tracking and Identifying Mammals, Birds, Reptiles, Amphibians, and Invertebrates
David Moskowitz$27.95 $25.16
This book focuses on the Northwest, but is useful across the continent. In addition to excellent drawings and photographs, the book includes rich information about the natural history of many species. In addition to the comprehensive information on mammals, it includes abbreviated sections on bird, reptile, amphibian and insect tracks and sign.
Lawrence Mark Elbroch, Michael Kresky, et al.$36.95 $33.26
Another regional guide that is useful far beyond California. This guide duplicates much of the information from Elbroch's Mammal Tracks & Sign guide, but in a more compact format. It also includes illustrations (but not text) of many bird tracks, plus a few herps and invertebrates.
Linda J. Spielman$19.95
Rather than show one "typical" track, this guide shows eight to ten variations of the footprints of species. The illustrations are not as detailed as those of Elbroch or Moskowitz, but the range Spielman shows makes this book a useful resource, especially for intermediate trackers. Printed on plain paper, the book may not hold up well in the field.
Eleanor Marks and Mark Elbroch$36.95 $33.26
This was the first, and so far only book dedicated to identifying bird tracks. Elbroch laid out a simple system for classifying and identifying avian footprints. It is the single best resource for identifying bird tracks in North America.
Filip A Tkaczyk$39.95
Filip Tkaczyk is a pioneer in exploring the world of reptile and amphibian tracks. This book is the only comprehensive guide to "herp" tracks in North America and establishes a great foundation.
Noah Charney and Charley Eiseman$49.95 $44.96
This first of it's kind book offers an overview of common sign left by invertebrates. In over 1,000 color photos and clear text it gives examples of eggs, webs, galls, feeding sign, droppings, burrows and tracks. With over 100,000 species of invertebrates in the U.S., no such text could be exhaustive, but this book strikes an excellent balance between breadth and depth in offering naturalists and trackers a truly useful overview of this vast field of study.
If you are wondering why I don't include my own guidebook on this list, it is because it is currently out of print while I work on the second edition. Watch for its release in early 2021.