“Moths of Western North America” is now in print!

Much to the delight of moth enthusiasts, the long-awaited and highly-anticipated field guide “Moths of Western North America” by Seabrooke Leckie is now available! This is the third field guide written by Leckie and completes the series covering the majority of the contiguous United States and Canada. While the previous two books (Northeastern and Southeastern) were part of the Peterson field guide family, this book is published by the well-known Princeton Field Guides. She has continued to improve all aspects of the field guide with each guide she has produced. This book consists of more than 600 pages, detailing 1,900 species with beautiful color photographs of live species at rest, as well as distribution maps, species descriptions, and more. A book by the same name was written by Jerry A. Powell and Paul A. Opler and published in 2009. While that book is well-respected and a great resource, this new book is appropriately branded as a field guide and appeals to a wider audience, in particular the growing number of citizen scientists who are more likely to photograph living moths than to collect, pin, and spread moths. This book is a must have for any moth enthusiasts who live in, or plan to visit, this vast and diverse region.

We reached out to Seabrooke Leckie and she was kind enough to answer some questions from us about the new book. 

This book seems like a massive undertaking. How long was this field guide in the works?

It was a lot of hours and years! I signed the contract for it in 2018, but due to certain external factors (such as an international pandemic, and preschool-aged children), work on the book was intermittent through the first four years. I was able to get back to it with more dedication in 2022 and worked on it fairly steadily around my schedule as a parent until its completion in summer 2025. So, seven years, across which I estimate I put in 3000+ hours.

How many different data sources did you use to create the distribution maps? 

It depends a bit on the species and how common it is. For more common species, the answer is just two as it’s easy to get a good understanding of its range simply from Moth Photographers Group and iNaturalist. For less common species, I also referred to other websites such as BugGuide, BOLD (DNA barcoding database), and Butterflies and Moths of North America, as well as print references like Powell & Opler’s Moths of Western North America, the Wedge Entomological Research Foundation’s Moths of America North of Mexico (MONA) fascicles, regional guides or checklists, and even the original species descriptions. In some instances, in addition to checking the available data for the moth I’d also look up the range of its host plant, as plants tend to be better documented on iNaturalist than most animals and invertebrates.

What was the most surprising thing you learned in the process of creating this guide?

Moths of Western North America is the third field guide I’ve completed, so there was little about the process of making it that was surprising. But I loved learning things about the species that were included in the book, many of which I’d never even heard about prior to this project. I think my absolute favourite moth I learned about is the Oso Flaco Flightless Moth (Areniscythris brachypteris). It’s a species of diurnal moth that inhabits sand dunes in California and is camouflaged to blend into the grains of sand. It lacks functional wings and instead runs along the surface of the sand, leaping into the air and letting the breeze carry it when it wants to move longer distances.

Now that you’ve completed the guide, do you have any trips planned to specific places in the west?

Oh goodness, how I would love to! Western North America is incredibly beautiful. No, I have nothing planned currently – it’s been tougher to travel far since having kids, so the most we’ve done with them has been trips to the ocean every summer, and even that’s a ten hour drive from where we are in eastern Ontario. I’ve traveled a fair bit to the west in my younger days, though – a university course in the southwestern deserts, a summer job searching for nests at Lake Tahoe, running a bird banding station in the Okanagan in BC, another trip out to Vancouver Island the following year for a different bird job. Each time I would drive myself out and do a bit of touring the region after the job before returning home to Ontario, so I’ve been through most of the west, though not since getting into moths. I’d love to get back and do some serious mothing.

It seems most (all?) of the moths in the Fieldguide have common names. Some of these names (like Raspberry Brocade) I can’t find in any online sources. Were all of these names out there in the world already or did you create some common names for this guide? 

For all three of the field guides, it was important to me that all the species have a common name. I find (and assume there are others out there who do too) that Latin words and names are much harder to remember than those in English. (Isn’t “Oso Flaco Flightless Moth” much easier and more meaningful than “Areniscythris brachypteris”?) Having English common names for all of the species makes mothing much more accessible and inviting to everyone – no one needs to feel daunted about remembering difficult names or worrying that they’re pronouncing it wrong. Also, misspellings and typos are much less likely for English names than scientific ones. And a common name will follow a species through taxonomic adjustments that may change the genus and sometimes even the species epithet, so it doesn’t require the moth-er to stay on top of taxonomic updates. North American birders, butterfliers, herpetologists and dendrophiles are not expected to know the scientific name of the organisms they watch; why should moth enthusiasts be any different?

Quite a lot of moth species have no common name yet, however, and as there is no organization overseeing the standardization of moth names (as there is for birds), creating common names falls to the people doing the publishing. I tried my best to track down pre-existing names where possible (giving priority to names used on BugGuide, Moth Photographers Group, or iNaturalist), but for all three of the guides, where no common name yet existed I coined one for the species. I tried to choose meaningful names. For some, I translated the scientific name directly. Many were named for some aspect of their appearance. Others were named after their range, their habitat, or their host plant. A few were named fancifully, but usually in keeping with others in the genus that had already been given fanciful names. In the case of Raspberry Brocade, I chose the name to pair well with Violet Brocade, which was already named; “raspberry” as a more poetic description of wine-red, the moth’s primary colour, just as violet is more poetic than purple. (Though I can’t pretend I didn’t also enjoy the musical pun: “She wore a raspberry brocade!”) During the process I invited public suggestions for species still missing names, thinking some people might have fun brainstorming and contributing ideas; interestingly, I only had one person submit anything!

There is still so much discovery happening with moths. Did you include any species in the book which were only recently described and named?

I think most of the species in the book are well-established taxonomically, although there were a bunch that were relatively recent taxonomic splits and were new that way. However, there are a couple that are so new, they haven’t even been officially described yet! These are in genus Donacaula, pg 204. They’re of phenotypes that I found were frequently reported to iNaturalist, with the identification based on unofficial descriptions given in an unpublished university thesis. They are just presented in the book as “n. sp.” (new species), until such time as either the thesis is peer reviewed and published, or someone else prepares and publishes a similar review of the genus. We did something similar for the Southeastern guide – the Florida False Pug (pg 420) was a new species at the time we were preparing the book (in 2016), but common; it was finally formally described in 2020, so we’ll be able to update that in the new edition.