Bay Nature Hike: Mount Diablo Butterflies

This event is inspired by Bay Nature's Fall 2025 piece, an excerpt from Liam O'Brien's upcoming book, Butterflies of the Bay Area, and (Slightly) Beyond

Join Bay Nature and lepidopterist and illustrator Liam O'Brien for a hike at Mount Diablo's Mitchell Canyon in search of butterflies on Sunday, September 28 from 11am - 2pm. We'll go for a gentle paced walk to search for butterflies on an out-and-back hike along a route featured in Liam's upcoming book. We'll pause partway along the route to eat lunch then continue on our way, keeping our eyes peeled for the more than 30 butterfly species that call this area home. This hike is free for Bay Nature Members. 

Meet Your Hike Leaders:

Liam O’Brien‘s stage career ultimately peaked with the performance on Broadway of Les Misérables for three years. A western Tiger swallowtail flew through the yard while he was doing a play at the Marines memorial in San Francisco. He bought a field guide that week and join the Lepidopterists’ Society later in the month. He has spearheaded many conservation projects in San Francisco around butterflies.: the Green Hairstreak Corridor, Tigers on market Street, variable checker spots and California ringlets back to the Presidio and Mission blues back to Twin Peaks. He is more proud of any of his conservation work than any moment on the American stage. Liam was the recipient of Bay Nature Magazine’s 2014 Environmental Education Award. 

Meet up location: Mitchell Canyon Parking Lot. 96 Mitchell Canyon Rd, Clayton, CA 94517. Google Maps Link. 

Hike length: This hike will be 3 miles long total. It will be an out and back hike.

Hike difficulty: This is an easy, flat hike with minimal elevation change.

Parking: Mitchell Canyon Parking Lot. 96 Mitchell Canyon Rd, Clayton, CA 94517. Google Maps Link. 

Weather Note: Be prepared for very warm temperatures, so bring lots of water, sun screen, and sun protection.

Access to restrooms and water: There are bathrooms available near our meet up location, but please plan to pack in 1-2 liters of your own water.

Other notes: Bring at least 2 liters of water, a packed lunch / snacks, sunscreen, a wide-brimmed hat, and sun protection. Comfortable, close-toed walking shoes are recommended. No dogs are allowed on Bay Nature hikes. All minors must be accompanied by a guardian for the duration of this event. Bring hiking poles, cameras, and binoculars if preferred. Please note you may encounter ticks, poison oak, and other hazards along the way.

Photo by © Ken-ichi Ueda, some rights reserved (CC-BY) via iNaturalist