Resources for Butterflying
Here are the resources I have depended on. It is often hard to make an exact identification, and I find it invaluable to have so many overlapping sources of information. Disagreements between the authors are as informative as they are frequent. A great aspect of multiple sources is that each is likely to convey some detail which the others don't—so in the normal situation that my photograph or observation gives only partial information, I find myself searching through all the books and websites for the critical, defining clue.
Robert Michael Pyle, The Butterflies of Cascadia, Seattle Audubon Society, 2002. The all-time best field guide, especially for butterfliers in or near Washington and Oregon. Descriptions, habitat and range discussions, life histories, and photos are extraordinary. Pyle's earlier Audubon Society Field Guide to North American Butterflies has similarly valuable discussions. This was the first field guide to rely on field photographs. Some of the butterfly names and details of classification used in the Audubon book are no longer used, but don't let that keep you from using the great descriptions of appearances, habitats, life histories, and distributions.
Jim Brock's Kaufman Field Guide to Butterflies of North America is the best contemporary continent-wide quick reference. For many of us it's the starting point to figure out an unfamiliar butterfly. (Two recent editions illustrated.)
Butterflies of America, butterfliesofamerica.com, is an extraordinary internet resource for understanding details and variations at the subspecies level. You may find it interesting to see the variation with each subspecies and between populations, and the overlapping of appearances of different subspecies and even species. If nothing else, this will help you understand the taxonomic (classification) disputes among lepidopterists, who rely on appearance, habitat, DNA analysis, and genitalic dissection in their studies. This site includes John Pelham's complete listing of species and subspecies from his book, (see the next entry), and with a few ongoing updates and revisions.
John Pelham's Catalog of the Butterflies of the United States and Canada, published as The Journal of Research on the Lepidoptera, Volume 40, 2002, is a very thorough listing of species and subspecies, with deep scholarly research into details of correct, historical and contemporary nomenclature. This listing is available online at butterfliesofamerica.com, and with several additional aspects in this book. I'm thrilled to have both forms available. The book is available from BioQuip.
Bioquip is a great source of supplies for collecting and of books. All new information comes from collected specimens. Though I usually just watch or photograph, I carry a net and will occasionally take a specimen. Sometimes I need it to study closely for identification or to ask an expert. If it's presence at that location seems unusual, lepidopterists studying butterfly subspecies distributions, habitats, and populations need to know just exactly which genetic variation I found. A specimen for inspection, or even dissection or DNA analysis becomes essential.
North American Butterfly Association is the place to go to find butterfliers and butterfly activities. Founder Jeffrey Glassberg has overseen the development of a vigorous organization. NABA has built a large, effective organization of amateur and professional naturalists studying and conserving butterflies.
The Butterflies Through Binoculars books by NABA found Jeffrey Glassberg are invaluable references. I use them regularly, for photos, descriptions, and biology. Warning: The the edition I saw of the poorly named Butterflies of North America excluded Canada, though it remains a good source on the United States. Don't remember if Alaska and Hawaii are covered.
State and Regional Guides
Such abound, and I recommend them all for the local knowledge and details they contain. Some are full books, others one-page guides. Far too numerous for me to know about or list them all, I only display my own:
North Coast Butterflies & Day Moths
That's the northwest Oregon coast.
My guide is published by the North Coast Land Conservancy, a magical organization for preserving habitat, building a conservation community, and education. It features life-size photos for quick visual reference, with repeated image fragments emphasizing key field marks, to train our eyes to look twice at those features.
In Butterflies of British Columbia, Crispin Guppy and Jon Shepard provide the most detailed range maps for subspecies, along with methodical specimen photographs and great discussions. Invaluable throughout the Pacific Northwest, not just in British Columbia. Wouldn't be without it.
Andrew Warren, Butterflies of Oregon: Their Taxonomy, Distribution, and Biology. (Lepidoptera of North America 6, Contributions of the S. P. Gillette Museum of Arthropod Diversity, Colorado State University.) In almost 300 pages of details, Warren delivers exactly what the title promises. Love it.