Butterflies and moths (click on an image for a larger view)
	Gray hairstreak (Strymon melinus), late summer, Sierra Azul Open Space Preserve Unknown, spring, Año Nuevo State Reserve Ceanothus silkmoth (Hyalophora euryalus), early spring, Austin Creek State Recreation Area California tortoiseshell (Nymphalis californica), winter, Coast Trail, Point Reyes National Seashore Boisduval's Blue? (Plebjus icarioides), spring, Stile Ranch Trail Unknown, spring, Old Quarry Trail, Mount Burdell Red admiral (Vanessa atalanta), summer, San Francisco backyard Painted lady (Vanessa cardui), summer, San Francisco backyard Variable checkerspot (Euphydryas chalcedona), spring, Mitchell Canyon Road, Mount Diablo State Park California sister (Adelpha bredowii), summer, Skyline Wilderness Park		Unknown, autumn, Ridge Trail, Russian Ridge Open Space Preserve Pale swallowtail (Papillo eurymedon), spring, Woods Trails, Sierra Azul Open Space Preserve Anise swallowtail (Papilio zelicaon), late winter, Red Hill Trail, Coyote Hills Regional Park Monarch (Danaus plexippus), late winter, Coyote Hills Regional Park Acmon blue (Plebjus acmon), spring, Stile Ranch Trail Mylitta crescent (Phyciodes mylitta), spring, Mitchell Canyon Road, Mount Diablo State Park Common buckeye (Junonia coenia), summer, Skyline Wilderness Park Spring azure (Celastrina ladon echo), late winter, Cascade Fire Road, Cascade Canyon Open Space Preserve Variable checkerspot (Euphydryas chalcedona), summer, Ridge Trail, Skyline Ridge Open Space Preserve Skipper, late summer, San Francisco backyard

Recommended reading:

• Field Guide to Butterflies of the San Francisco Bay and Sacramento Valley Regions, by Arthur M. Shapiro and Timothy D. Manolis (order this book from Amazon.com).
• Butterflies through Binoculars: the West, by Jeffrey Glassberg (order this book from Amazon.com). A new favorite, this book has very good photos, plus loads of information about butterfly behavior. For example, the author advises looking for anise swallowtails on hilltops (once I read this I had a major "of course" moment, since everytime I've seen anise swallowtails, they've been on top of hills).
• Common Butterflies of California, by Bob Stewart (order this book from Amazon.com). Beautiful photos, and a good source for bay area butterfly identification.
• An Obsession with Butterflies, by Ahrman Apt Russell (order this book from Amazon.com). A sweet little book packed with little tidbits about butterflies and moths. I particularly enjoyed reading about butterfly behavior, including how butterflies find host plants: they look for familiar leaves, then land on contenders and "taste" the leaves with their feet.

Links:

Butterflies and Moths of North America http://www.butterfliesandmoths.org/