Identifying U.S.A. and Canadian Butterflies on iNaturalist: An Overview
My first journal post!
I’ve identified a lot of U.S.A./Canadian butterflies on iNaturalist during the last few years. So, I thought it might be useful to collect in one place some of the big-picture taxonomic information and resources I had to scrounge around for when first starting out, which hopefully will help others trying to figure out the same sort of things.
Big Picture: Taxonomy
For some taxonomic and/or geographic areas, iNaturalist uses specific sources for determining its taxonomy. As discussed in this forum post, iNaturalist uses...
A Catalogue of the Butterflies of the United States and Canada, and
Illustrated Lists of American Butterflies (North and South America)
...as its taxonomic authorities for North American butterflies.
These are amazing resources! If a butterfly species exists in the U.S.A. or Canada, you’re going to see it in Pelham’s U.S.A./Canada Catalogue. And if it exists in the western hemisphere, you’re going to see it in Warren et. al.’s Illustrated Lists.
Theoretically, iNaturalist’s butterfly taxonomy should basically match these lists. Sometimes: (1) we have decided to deviate, (2) things are complicated by taxa also existing outside the western hemisphere (where we don’t have taxonomic authorities, or those authorities disagree), (3) the Catalogue and the Illustrated Lists don’t agree, or (4) we haven’t brought things up to date yet, because there are a lot of species and only so many people working taxonomy.
But generally, iNaturalist’s taxonomy does indeed match these lists.
Additional Helpful Online Taxonomic Resources
BugGuide
This website has a ton of useful data on all North American insects, including butterflies. It's also iNaturalist's default taxonomic resource for North American insects other than butterflies. Sometimes the site has helpful identification tips for butterflies and their subspecies.
Butterflies of North America (Howe, 1975)
This is a great resource, and it's available for free via the Internet Archive if you register. Some of its taxonomy is a bit outdated, but generally not enough to matter. Also, if you'd like to know the physical differences between any given USA butterfly subspecies, then this book often has the answer.
Butterflies of Canada
This is basically an online version of Layberry, Hall, and Lafontaine’s 1998 book, and it does an excellent job of describing each of the 300 or so butterfly species found in Canada.
Funet
I wouldn't necessarily characterize this website as user-friendly. And it's not necessarily very helpful for identification. But over and over again, if I'm trying to track down the original historical taxonomic source, I wind up here. And often, there's an electronic link to that source. Kind of fun, and quite useful if you’re into that sort of thing!
There are obviously a million other helpful online resources, but the above are those I find myself most consistently checking.
My Favorite Field Guide
Although mostly only available in print (best I can tell, and at least legally), Ken Kaufman’s Field Guide to Butterflies of North America is amazing. List price is only $25 USD (and it’s typically cheaper on Amazon; $17 USD as of December 2025). While I haven’t spent too much time with some of the other more-or-less comprehensive guides to U.S.A./Canadian butterflies, I have skimmed many of them. They seem fine, but I nonetheless recommend Kaufman.
Conclusion
Generally when learning a new species (and of course depending on how complicated things seem), first I start on iNaturalist (especially the “Similar Species” tab), then I move to Kaufman, and then, depending on circumstances, I check the other resources.
Anyway, I hope all this helps somebody!
