The Memorial Day weekend is upon us, marking the customary start of the summer season. And several East Bay regional parks are observing the occasion with open houses and other activities.

Let's start with Ardenwood Historic Farm in Fremont. Normally, Ardenwood charges an admission fee, but on Memorial Day, the farm will host a free open house from 10 a.m. to 4 p.m. Activities will include helping with the morning chores from 11 a.m. to noon, rides on the unique horse-drawn train, tours of the historic Patterson House, cookies at the Country Kitchen from 11 a.m. to 1 p.m. and old-time games on the house lawn from noon to 1 p.m.

From 2 to 3 p.m. you can stroll around with a naturalist and learn what life was like on the farm a century ago. The animals get their afternoon feed at 3 p.m. Ardenwood is at 34600 Ardenwood Blvd., just north of Highway 84. Parking is free. For more information, call 510-544-2797.

Up the shoreline in Alameda, Crab Cove Visitor Center will hold open house from 10 a.m. to 4 p.m. Memorial Day. There's a self-guided history walk available all day. Family bird watching is from 10 to 10:45 a.m., there's a pond walk from 2 to 2:45 p.m., a fish feeding program from 3 to 3:30 p.m. and bring your mud boots for a low-tide exploration of the cove from 3:30 to 4:15 p.m. Or stop in to meet the center's turtle and snake, make a nature craft and more. It's fun for the family all day long.

Crab Cove is at 1252 McKay Ave. off Central Avenue in Alameda. If the McKay Avenue lot is full, you can park at the Crown Beach lot, with its entrance at the intersection of Otis and Shore Line Drives. For information, call 510-544-3187.

There's also an open house in Berkeley from 11 a.m. to 3 p.m. Memorial Day Monday at the Environmental Education Center in Tilden Nature Area. Highlights will include farm activities, crafts, nature exploration and homemade ice cream samples.

Naturalist James Wilson will lead two other programs at Tilden on Sunday. One is "The Truth About Bees" from 10:30 a.m. to noon. It's about the importance to the environment of our six-legged friends. The other is "Green House Giveaway" from 2 to 3:30 p.m. Learn about edible plants from seeds to sprouts. To get to the center, park at the end of Lone Oak Road off Tilden's Central Park Drive and follow the signs. It's about a quarter-mile walk. For information, call 510-544-2233.

At Black Diamond Mines Regional Preserve in Antioch, there's an early morning walk to Rose Hill Cemetery from 8 to 10 a.m. Sunday led by naturalist Ashley Elliott. Rose Hill is the burial site for many of the miners and their families who lived and worked in the 19th century mining towns. It's about a half-mile, uphill walk to the cemetery. Meet Ashley at the uppermost parking lot on Somersville Road, five miles south of Highway 4.

Black Diamond Mines doesn't normally offer tours of the underground mining museum on Mondays, but on Memorial Day Monday tours are scheduled at 11 a.m., noon, 1 p.m., 2 p.m. and 3 p.m. Tickets can be purchased for $5 per person, first-come-first-served at the underground Greathouse Visitor Center starting at 10 a.m. For safety reasons, mine tours are open only to ages 7 and older.

Black Diamond Mines has a parking fee of $5 per vehicle. For more information, call 888-327-2757, ext. 2750.

HOLIDAY TIPS: Just in general, Memorial Day tends to be one of the busiest days of the year in the regional parks, especially at parks that have swim facilities. Picnic tables and barbecue stands are available on a first-come-first-served basis, so it's advisable to arrive early in your favorite park.

If all the picnic areas are full, it's fine to spread a blanket and picnic on the lawns. Portable barbecues are permissible on lawns but not on adjacent dry grasslands. Fire is a major concern, especially because of the ongoing drought. Dispose of barbecue coals only in the concrete receptacles designed for that purpose, not in the regular trash barrels. If you're out hiking on the trails, be sure to carry an ample supply of water. Protect yourself against sunburn, and pick up a park map at the trailhead.

In the last column I offered some safety hints for swimming in the regional parks. Complete information on locations, hours of operation and fees is available at the park district website, www.ebparks.org. You can also download park maps from that site. In the event of an emergency, be sure to follow any and all instructions from police, firefighters, lifeguards and park rangers.

CHABOT REGIONAL: There's a family-friendly Saturday Stroll scheduled from 10 a.m. to noon May 24 at Anthony Chabot Regional Park. This one is a bit longer -- it's a moderate 4-miler to the edge of Lake Chabot in hopes of spotting the bald eagles that are nesting there.

Meet at the Clyde Woolridge Staging Area in Oakland. It's located at the intersection of Skyline Boulevard and Grass Valley Road in the Oakland hills. For information, call 510-544-3187.

HUMP DAY HIKING: The Wednesday Walkers will hit the trails at Brushy Peak Regional Preserve near Livermore in a moderate-to-strenuous 4.25-mile hike starting at 9:30 a.m. Wednesday.

Brushy Peak is a frequent hangout for birds of prey including golden eagles. I've seen an eagle almost every time I've been there. They like to feed on the abundant population of ground squirrels in the grasslands.

Meet at the trailhead at the end of Laughlin Road. To get there, exit Interstate 580 at Vasco Road and head north toward Brentwood. But almost immediately, turn right onto Northfront Road. In a mile, turn left on Laughlin Road and drive to the end. For information, call 888-327-2757, ext. 3212.

member benefits: By the way, if you are a frequent visitor to the regional parks, becoming a park member is a really good deal. Memberships are available at the individual and family level.

Benefits include unlimited day use parking, one annual dog pass, free swimming during the swim season, free admission to Ardenwood Historic Farm on nonevent days and free mine tours at Black Diamond Mines. For information about fees and benefits, visit www.regionalparksfoundation.org.

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