Overview:
These sites feature one Discovery Channel moment after another, minus the TV and cable bill.
On the northern edge of the Bay Area, Point Reyes National Seashore hosts a herd of tule elk -- imposing bulls lording over their harems -- best seen on a hike along the Tomales Point Trail. The hike is a flat 10-mile out-and-back, but it's easy to see elk without hiking the whole distance.
Just north of San Francisco stands the Marin Headlands, home to countless sea birds and an impressive show of wildflowers every spring.
Año Nuevo State Preserve south of Pacifica is home to large colony of elephant seals; they're so popular that you need reservations to see them during the peak winter season.
Point Lobos State Reserve is over 100 miles south of San Francisco, so it's a bit of a reach to say it's in the Bay Area, but the scenery and and wildlife are so rich that any visit to the region must include a stop there.
Tips:
Keep your distance from large mammals, particularly elk and elephant seals, which can move with astonishing speed and crush/gore anybody they see as a threat. Never forget these are wild animals.
Dress for cold weather; warmth is rare along the Pacific Coast.