After the sedentary pleasures of the Thanksgiving holiday -- turkey and TV football -- the East Bay regional parks stand ready to help you work off the extra calories.

For instance, Crab Cove Visitor Center in Alameda plans a full day of family-friendly activities from 10 a.m. to 4 p.m. Saturday. The schedule includes close-up encounters with live fish, crabs, turtles and a gopher snake, nature walks, and nature-themed crafts for the kids.

From 10:30 a.m. to 12:15 p.m. there's a big-screen program about Bay and ocean wildlife, accompanied by popcorn and cider. From 1 to 2 p.m., naturalists will lead a hike to see the shorebird feeding frenzy on the mud flats. Low-tide exploration is from 2 to 3 p.m., and fish feeding is at the aquarium from 3 to 3:30 p.m.

All the programs are free. Crab Cove Visitor Center is located at 1252 McKay Ave. off Central Avenue in Alameda. For more information, call 510-544-3187.

'shroom season: Fungus will be the focus of a free program from 1 to 3 p.m. Sunday at the Environmental Center of Tilden Nature Area in Berkeley, led by naturalist Trent Pearce.

Trent will talk about how to identify common types of mushrooms, then he'll lead a hike to see what is growing in the park. If you join him, bring a snack. The center is located at the north end of Tilden's Central Park Drive. For more information, call 510-544-2233.

There's also a no-pick mushroom walk scheduled from 10 a.m. to noon Dec. 1 at Redwood Regional Park in Oakland, guided by Debbie Viess of the Bay Area Mycological Society, Dan Rademacher of Bay Nature Magazine and a park district naturalist.

It's a moderate hike with some hills, and it will go rain or shine. It's free, but registration is required. For registration and information, call 888-327-2757. Select option 2 and refer to program 30903.

While we're on the subject of mushrooms, here's a word of caution. This time of year, you're likely to see mushrooms all over the place in the regional parks and other open space. Some varieties are edible, others are not only inedible, they can be deadly poisonous.

No one should pick wild mushrooms unless he or she is an expert at mushroom identification. For the rest of us, the best place to gather them is your local supermarket. In any case, it's against the rules to harvest mushrooms or any other plant in the regional parks.

FLYING FAUNA: If mushrooms don't appeal to you, how about bluebirds and butterflies? Park district naturalists will lead one of their Sunday Strolls in search of the winged beauties, from 10 a.m. to noon Sunday. The moderate, 3¾-mile hike starts at the Trudeau Staging Area, 11500 Skyline Blvd., Oakland. For more information, call 510-544-3187.

NATURE STORIES: And it's fireside story time from 10:30 to 11:30 a.m. Sunday at Tilden's Environmental Education Center. Sit by a warm fire with a cup of hot chocolate and listen to some nature stories from naturalist aide Morgan Rani Evans. You can share some of your own stories, too.

'DUCK, DUCK, GOOSE': Children ages three through five accompanied by a parent will enjoy a free program from 10 to 11:30 a.m. Dec. 6 at Shadow Cliffs Regional Recreation Area in Pleasanton led by naturalist Katie Colbert. It's "Duck, Duck, Goose," a visit with our web-footed friends, of which there are plenty at Shadow Cliffs.

Registration is required. There is a $6 fee, $8 for non-residents. Call 888-327-2757 and refer to program 30610.

WOMEN'S HIKE: Katie also hosts "Women on Common Ground," a series of programs for women who love the outdoors but have personal safety concerns. She'll lead a women's hike from 9 a.m. to 2:30 p.m. Dec. 15 at Pleasanton Ridge Regional Park in Pleasanton. It's a five-miler to explore old olive groves, with an open house at Hillcrest Ranch.

The program is free; registration is required. For information, call 510-544-3243. To register, call 888-327-2757 and refer to program 30703.

Ned MacKay writes a regular column about East Bay Regional Park District sites and activities. Email him at nedmackay@comcast.net.