I am a freelance naturalist based in western Massachusetts and working throughout New England. My passion is to continually deepen my connection with my natural surroundings and help others to do the same. I do this through research, writing, photography, teaching, leading natural history walks, giving slide show presentations, and conducting plant and animal surveys. I have served as the Aton Forest Fellow since 2022, and in 2024 I was honored to receive awards from the Linnean Society of London and the Maxwell | Hanrahan Foundation in recognition of my work on insect natural history.
I am the lead author of Tracks & Sign of Insects and Other Invertebrates (Stackpole Books, 2010), and continue to collect photographs and information on this subject. I share some of my latest observations on my blog, BugTracks. I am especially interested in the signs left by herbivorous insects on their host plants, and have been studying leafminers intensively since 2011. A second edition of my e-book, Leafminers of North America, is now available, and I am currently releasing the third edition in monthly installments while working on a similarly hostplant-based guide to North American sawfly larvae.
For more information about my ecological consulting services, see this page. A list of past clients is included in my CV.
You’ll get a pretty good idea of what I’m all about by perusing my blog, but the following articles, podcasts, and book chapters have some more information about me and my work:
Hanson, Thor. 2025. Close to Home: The Wonders of Nature Just Outside Your Door. New York: Basic Books. 287 pp. [includes a section about my work, and my yard and its inhabitants]
McPhaul, Meghan McCarthy. 2024. Documenting Natural Resources and Interesting Insects with Charley Eiseman. Northern Woodlands.
Roach, Margaret. 2022. Those Weird Marks on Your Leaves? Here’s How to Decipher Them. The New York Times.
Hawk, Michael. 2020. Charley Eiseman – Naturalist, Author, Innovator, and Leaf Mining Insect Specialist. Nature’s Archive. [podcast]
Candeias, Matt. 2017. Leaf Miners. In Defense of Plants. [podcast]
Horowitz, Alexandra. 2016. Being a Dog. New York: Scribner. 368 pp. [includes a section about the “Ecology Through Animal Tracking” course I used to teach with Noah Charney]
Horowitz, Alexandra. 2013. On Looking: Eleven Walks with Expert Eyes. New York: Scribner. 308 pp. [includes a chapter about exploring a city block with me]