Leader Bios

When you join a Yosemite Conservancy Outdoor Adventures program, you will have quality time in the field with some of the most knowledgeable and talented naturalists, historians and artists in Yosemite. Collectively, they’ve hiked tens of thousands of miles in the park, won numerous awards, authored dozens of books, and had their art or photographs published around the world. Our people are excited to share their passion for Yosemite with you.


KAREN AMSTUTZ is a California native with a master's in environmental education. She has more than 15 years of experience working in Yosemite. She has taught for NatureBridge and has worked as a National Park Service ranger in Tuolumne Meadows, where she is well-known for her campfire programs. Karen lives with her family in El Portal and loves to share her extensive knowledge about the natural world.

Snowshoe Yosemite: Dewey Point 2

ALLISON BAGGETT grew up in a small town at the entrance to Yosemite. She has backpacked from Mr. Whitney to Canada on the Pacific Crest Trail and from Portland, Oregon, to Missoula, Montana, following the route of Lewis and Clark. Allison has worked as a teacher, naturalist, mountain guide and artist since graduating from The Evergreen State College in Olympia, Washington. She has been trained as a Wilderness Emergency Medical Technician and currently holds a Wilderness First Responder certificate.

Beginner Backpack Trek to May Lake

KYLIE CHAPPELL grew up in the Yosemite gateway, Mariposa. She has always enjoyed a love for the outdoors including rock climbing, backpacking, skiing and swimming. After traveling abroad to New Zealand, Australia and China she couldn’t wait to return to her roots and settle in Yosemite. She has worked as a horseback riding guide and packer in Yosemite for three years. As the Outdoor Adventure Coordinator for Yosemite Conservancy, Kylie is able to share her love and knowledge of Yosemite with visitors from all over the world.

Clouds Rest Day Hike

PETE DEVINE has taught outdoors in Yosemite for 20 years. Originally from New England, Pete has worked in the West as a park ranger, archeologist, river guide, naturalist and teacher. As Yosemite Conservancy’s resident naturalist, Pete has explored Yosemite extensively and can provide insider knowledge about the park’s natural and cultural history. You can also see him in the popular Yosemite Nature Notes frazil ice video.

Beginner Backpacking Workshop
Secrets of the West Valley
Leave No Trace Trainer
Solstice Backpack Trek to Devil’s Dancefloor
Hike Half Dome: Summit Challenge 1
Lyell Glacier Backpack Trek
The Day of the Woodpecker

DICK EWART, a veteran hiker and winter enthusiast, has been a park ranger in Yosemite for more than 30 years. He has a bachelor’s degree in biol­ogy from the University of New Hampshire and has hiked and snowshoed most of the park’s 800 miles of trails. Dick spends his summers presenting naturalist programs at Glacier Point; during the winter, he enjoys leading snowshoe hikes at the Badger Pass Ski Area.

Snowshoe Yosemite: Mariposa Grove 1
Snowshoe Yosemite: Dewey Point 1
Young Lakes Backpack Trek
Ice, Wind & Fire

PETER HEMMING grew up in Los Angeles and now lives on the Monterey Peninsula. He is a featured Nikon photographer who has been published in hundreds of periodicals and websites around the world. He is a member of the Explorers Club and has extensive experience traveling in the High Sierra, with a particular focus on the Tuolumne Meadows area.

Yosemite Photography: High Country Workshop

DAVID LUKAS is a popular and knowledgeable naturalist who has been leading programs in the Sierra Nevada and writing natural history books for over 20 years. He is the author of the revised guidebook “Sierra Nevada Natural History” and the new comprehensive guidebook, “Sierra Nevada Birds” in addition to contributing to 40 additional books. David lives in Groveland, Calif. and delights in leading visitors on hikes in Yosemite.

The Lives of Birds: Yosemite Valley
The Lives of Birds: Tuolumne Meadows
Sierra Nevada Natural History

JULIA PARKER has lived and worked in Yosemite for more than 50 years. She is the park’s longest-tenured employee. As a “living legend,” Julia has dedicated her life to preserving and communicating traditional American Indian cultural history and inspiring visitors to be responsible environmental stewards. She has studied under master weavers and currently demonstrates basket-weaving techniques at the Yosemite Museum. Her handiwork is highly sought-after, and several of her baskets are displayed in prominent museums and collections all over the world.

Miwok-Paiute Basketry

LUCY PARKER is descended from a long line of Yosemite cultural interpreters. Brought up in a traditional cradle basket, Lucy worked in the park as an Indian cultural demonstrator for many seasons. She has also performed living history at Bodie State Park and demonstrated traditions of the Paiute people at the Lee Vining Visitor Center.

Miwok-Paiute Basketry

JOHN RICCA is a San Francisco Bay Area professional fine art photographer who uses the camera to capture moods and visual experiences usually associated with other visual art forms. He focuses on natural and close-up images that emphasize shapes, textures, and patterns. In addition to being a photography guide for Yosemite Conservancy, he tutors individuals and small groups in photography workshops and field trips on how to improve their photographic techniques. He has exhibited in numerous group and solo exhibitions throughout the Bay Area.

Yosemite Photography: Focusing on Nature

KEN ROCKWELL is a talented photographer and host of a popular website for essays, photo galleries, lessons and equipment reviews. Having fully embraced the digital age, Ken is equally adept with traditional 35mm, panoramic, medium and large format photography. An engineer by training, Ken has an artistic eye and is excited to share his knowledge and opinions about photography.

Yosemite Photography: Spring Light
Yosemite Photography: Autumn Light

MICHAEL ELSOHN ROSS has led outdoor and custom adventures for Yosemite Conservancy since 1977. He is the award-winning author of 42 books for young people, including Baby Bear Isn’t Hungry, The Happy Camper Handbook, The World of Small and Snug as a Bug. He teaches children’s-book writing workshops and is a popular speaker at schools and conferences around the world. Michael is passionate about sharing Yosemite’s diversity with newcomers and longtime park enthusiasts. He lives with his family near the park in a home overlooking the Merced River.

Spring Canyon Flowers
Yosemite Birding
Yosemite’s Springtime Birds & Blooms
Exploring the Rim Fire
Mountain Wildflowers for the Relaxed Botanist
Casual Birding at White Wolf
Tuolumne Alpine Insider: Life at the Top
Tuolumne Meadows Birds & Blooms
North Dome & the Natural Arch Day Hike
Go Climb a Peak: Summit Mt. Hoffmann
Mariposa Grove Birding

JOHN SENSER is an accomplished landscape and wildlife photographer/writer. His images have appeared in Sierra Club calendars and National Geographic publications, and he is regularly featured in Central Sierra Seasons magazine. He has conducted numerous courses and workshops for organizations including the University of California and Columbia College. As the owner of Yosemite Light Photography, he produces finely crafted photographic prints and notecards that are sold at art shows and galleries around California.

Yosemite Photography: Nature's Firefall & Winter Landscapes
Yosemite Photography: "Moonbow" 1
Yosemite Photography: "Moonbow" 2

SHIRLEY SPENCER is a renowned artist, musician/singer, athlete and educator. She is also the author/illustrator of Yosemite Conservancy’s Flowering Shrubs of Yosemite and the Sierra Nevada and co-author (with her husband, Mark) of Southern Yosemite Rock Climbs. Since the 1980s, thousands have been lucky enough to explore Yosemite with Shirley and share her infectious affinity for the outdoors.

Snowshoe Yosemite: Mariposa Grove 2

SARAH STOCK is a wildlife biologist at Yosemite National Park, where she studies songbird population dynamics, great gray owl conservation and bat ecology. Before moving to Yosemite Valley, Sarah was a migratory field biologist working with endangered species in Alaska, the Mariana Islands, Hawaii and the Big Sur Ornithology Lab. She earned her master’s degree at the University of Idaho and has authored many technical reports and peer-reviewed publications on western landbird status, ecology and management.

The Lives of Birds: Yosemite Valley

SUZANNE SWEDO is the director of W.I.L.D. and has backpacked the mountains of every continent. She has led groups into the backcountry for more than 30 years. She teaches wilderness survival and natural science for individuals, schools, universities, museums and organizations, including Yosemite Conservancy and the Sierra Club. She has authored numerous books and has appeared on radio and television to share her knowledge of backpacking, botany and wilderness survival.

Glen Aulin Backpack Trek
Hike Half Dome: Summit Challenge 2
Clouds Rest Backpack Trek 1
Hike Half Dome: The Easy Way
Vogelsang Backpack Trek
Hike Half Dome: Summit Challenge 3

HEATHER SULLIVAN co-founded and served as the first Executive Director of Balanced Rock and is now the Program Director. Heather is both a yoga instructor and an accomplished backcountry guide with Yosemite destinations and trips in the Himalayas. She has been a NatureBridge (formerly Yosemite Institute) field instructor, a Volunteer Mountaineering Ranger in Denali National Park in Alaska, and Naturalists at Large instructor. Her yoga classes blend Ashtanga flow, Iyengar alignment, a strong connection to the rhythms of the natural world.

Solstice Backpack Trek to Devil’s Dancefloor

CHRIS VAN WINKLE  is an award-winning California artist who has served as president of the National Watercolor Society. He was also selected as one of the top 20 art instructors by “Watercolor Magazine.” For the past 30 years, Chris has taught watercolor at Citrus College in Southern California.

Quick Sketching in Watercolor

CHARLES WALDMAN started pursuing a career as a full-time fine-art painter in 1999 after practicing family medicine in Sonora, Calif., for 22 years. He was selected as an artist member of the California Art Club, The Laguna Plein Air Painters and “The Sea-to-Shining-Sea” exhibition. He shows in galleries throughout the country, attends plein air events and teaches numerous workshops. Chuck loves to paint outdoors in the Sierras and enjoys sharing his artistic vision and philosophy with others.

Painting Tuolumne Meadows en Plein Air

KEITH WALKLET is a highly admired photographer and author, whose images have been published in Audubon calendars, Backpacker magazine and National Geographic. His stunning photography books include Yosemite: An Enduring Treasure and First Light: Five Photographers Explore Yosemite’s Backcountry. Keith enjoys teaching the fundamentals of photography and how to get the most from one’s equipment. After living and working in Yosemite for 14 years, Keith and his wife now reside in Boise, Idaho.

Yosemite Photography: Focusing on Nature

DAVE WYMAN is an accomplished photographer and author of three pictorial guidebooks (Backroads of Northern California, Backroads of Southern California and Yosemite in Photographs). His photographs and articles have appeared in Outdoor Photographer, Outside, Backpacker, Sky and Telescope and many other publications. He is an experienced guide, leading tours for environmental organizations and museums, in addition to photography tours and workshops through his company, Image Quest. He enjoys sharing his passion for photography and the outdoors.

Yosemite Photography: Spring Light
Family Camping Jamboree 1
Family Camping Jamboree 2
Yosemite Photography: Autumn Light

GLEN YOUNG was born in the flatlands of Michigan. After completing a Master’s in Park, Recreation, and Tourism Management in New Zealand, Glen worked as an alpine guide, and in the fields of international, environmental, and outdoor education throughout the United States (including Alaska and Hawaii). He also worked abroad in Canada, Thailand, Laos, Cambodia, Vietnam, Burma, Malaysia, Singapore, Nepal, Australia, New Zealand, Ecuador, and Peru where he led study abroad programs and adventure education activities.

Clouds Rest Backpack Trek 2