There's a new feature worth checking out at the Big Break Visitor Center in Oakley -- a 28-by-8-foot mural depicting Delta land and water plants and animals.

River otters, pelicans, a heron, Chinook salmon, bass, bluegill and other species all crowd the canvas, giving park visitors an idea of the diversity that characterizes California's vital waterway.

The mural was painted by artist Ali Pearson and her assistant, Bridget Keimel, both of Alumni Exhibits in Sebastopol. In preparation for their work, the two took kayak trips from Big Break to see the habitat for themselves. Then they worked in their Sebastopol fabrication shop for 10 weeks to complete the project. Regional park district staff helped with the installation.

Pearson grew up in a family of professional biologists, including her father, Oliver Pearson, who was a professor of invertebrate zoology at UC Berkeley. She has worked in the fabrication field for 20 years, creating exhibits for Yosemite National Park, Point Reyes and the Lindsay Wildlife Museum among other venues.

Big Break Visitor Center is on Big Break Road off Highway 4 in Oakley. Center hours are 10 a.m. to 4 p.m. Saturdays and Sundays. For information, call 510-544-3050.

SEE THE PARADE: Along with lots of other organizations, the East Bay Regional Park District will participate in the Dublin Lions Club's annual St. Patrick's Day parade. A contingent from the district's Volunteer Trail Safety Patrol will pass in review on foot, bicycle and horse.

The parade starts at 9:30 a.m. Saturday on a 1-mile route following Dublin Boulevard to Village Parkway, Amador Valley Boulevard and then ending at Donlon Road. If you're in the neighborhood, come out and cheer them on.

St. pAT'S HIKE: Naturalist "Trail Gail" Broesder will lead a more strenuous stroll from 9:30 a.m. to 3:30 p.m. Sunday, the actual St. Patrick's Day. It's a 10.5-mile trek from Sunol Regional Wilderness to the top of Mission Peak and back, a 2,200-foot elevation gain, intended for ages 12 and older. Views from the summit are among the best in the Bay Area.

Meet at Sunol's Old Green Barn visitor center. Bring lunch, liquid and $2 to pay for a wilderness permit. Sunol also has a $5 parking fee when the kiosk is attended. For information, call 510-544-2233.

A LITTLE EASIER: A less strenuous St. Patrick's Day walk is on the calendar for 10 a.m. to noon Sunday at Martin Luther King Jr. Regional Shoreline in Oakland. It's a free walk on the San Francisco Bay Trail to learn about plants that subsist on salt water. Wearing of the green is encouraged.

Meet at the Arrowhead Marsh staging area, which is at the end of a road leading into the park from Swan Way. For more information, call 510-544-3187.

green, green, green: Continuing the color scheme, interpretive student aide Melissa Tarnowski will lead a search for all things green, on a walk from 1 to 2 p.m. on -- when else? -- Sunday, St. Patrick's Day, at Sunol Regional Wilderness in southern Alameda County. It's free of charge, but registration is required. To register, call 888-327-2757, option 2, or go to www.ebparksonline.org.

EQUINOX: Wednesday is the vernal equinox, the official start of spring. Naturalist Cat Taylor will mark the occasion with a program from 6:30 to 9 p.m. at Del Valle Regional Park south of Livermore. Participants will bring their own food and flashlight for a two-mile walk to a picnic dinner by the lake.

The program is for ages 7 and older. Meet at the boat launch ramp. Del Valle charges a parking fee of $6 per vehicle. For information, call 510-544-3242.

CHABOT WALK: Also on vernal equinox Wednesday, the Wednesday Walkers will explore the northeast side of Lake Chabot on a somewhat strenuous 5-mile loop. Wednesday Walkers are an informal hiking group led by park district naturalists, and everyone is welcome.

For the Lake Chabot hike, meet at the Marcial Gate entrance to Anthony Chabot Regional Park on Redwood Road. Marcial Gate is about 5 miles south of the intersection of Redwood Road and Skyline Boulevard in Oakland. For information, call 510-544-3282.

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