Participants in the East Bay Regional Park District's Trails Challenge will soon have some low-tech but effective help in following the trails they decide to explore.

Help comes in the form of inch-wide rubber bands around the signposts at strategic junctions on the featured trails. Now being installed by volunteers, the bands are printed with the legend "Trails Challenge 2013" and are color-coded to indicate the level of hike difficulty. Green stands for easy, yellow for moderate and red for challenging.

Challenge participants can also download a guidebook with a map and detailed description of each trail. Those are the best guides; the rubber band markers are just an extra help. Please don't remove them to keep as souvenirs; leave them in place for other hikers. Challenge participants receive commemorative pins upon completion of the program.

For more information on the Trails Challenge program, visit the park district website at www.ebparks.org and click on the Trails Challenge photo on the right side of the home page. There's still plenty of time to register; the challenge goes on all year.

Orange peel problem: While we're on the subject of trails, I might as well mention an unfortunate byproduct of their use -- discarded citrus peels. The worst example I've seen is the summit of Mission Peak in Fremont, where peels are sometimes scattered over the landscape like post-Super Bowl confetti. I assume people celebrate their successful ascent by having a snack, but then discard the inedible rind instead of packing it out.

Yes, orange peels will biodegrade eventually, but it takes forever, partly because most animals don't like the taste any better than we do. In the meantime it creates an unsightly mess on the landscape. I'm probably preaching to the choir here, but please hang on to your trash until you pass a litter barrel. The same goes for empty bottles and aluminum cans. There are recycling bins at many trailheads.

Docent training: If you enjoy teaching kids and adults, too, about the natural and cultural history of the regional parks, think about becoming a docent at Sunol Regional Wilderness in southern Alameda County. Docents help the park district naturalists teach outdoor weekday school programs at Sunol and other regional parks in the area. Docent training will get under way in March at a date to be determined. For more information, contact naturalist Katie Colbert, Sunol's docent coordinator, at 510-544-3243.

TILDEN: For a free, easy, late winter nature walk, join naturalist Anthony Fisher from 1 to 3 p.m. Sunday, starting at the Environmental Education Center in Tilden Nature Area, Berkeley. The group will look for signs of early spring. The center is located at the north end of Tilden's Central Park Drive. For information, call 510-544-2233.

WEDNESDAY WALK: Redwood Regional Park in Oakland is the venue for a Wednesday Walk next week, led by naturalist aide Jenna Scimeca. Meet Jenna at 9:30 a.m. at the Chabot Space and Science Center on Skyline Boulevard in Oakland for a 5½-mile hike through the redwoods. Jenna will recount how early-day sea captains used the skyline redwoods as markers to help them navigate the Bay. Wednesday Walkers is an informal group of hikers who explore a different regional park each week. Hikes vary in difficulty, but everyone is welcome. For details, visit the hiking page at www.ebparks.org.

newts, anyone?: Newts, rock mazes and panoramic views are among the attractions at Sibley Volcanic Regional Preserve in the Oakland hills. Naturalist Sara Fetterley will lead a moderate, 2.6-mile walk there Saturday. Meet Sara at the park entrance on Skyline Boulevard a short distance south of the intersection with Grizzly Peak Boulevard. For details, call 510-544-3187.

SAN RAMON FUN: As naturalist Cat Taylor says, "When it rains, it spores." She's talking about mushrooms, and she'll lead kids and parents on a hunt for the fungi from 10 to 11:30 a.m. Feb. 21 at Las Trampas Regional Wilderness in San Ramon.

This is one of the Outdoor Discoveries series, designed for children ages 3 through 5 and a parent. It takes place rain or shine. Meet at the parking lot at the north end of Bollinger Canyon Road. Registration is required, and there's a fee of $6 per child ($8 for nondistrict residents). There's a $3 fee for each sibling who attends; parents can come for free. For details and registration, call 888-327-2757. Select option 2 and refer to program 1121.

BRIONES: Women on Common Ground is a program led by naturalist Katie Colbert, designed for women who enjoy the outdoors but are concerned for personal safety. The group will explore Briones Regional Park near Martinez in a hike from 9 a.m. to 1:30 p.m. Feb. 24. It's a 4-miler from the Alhambra Creek Staging Area up to some newt ponds. Katie's hike is free, but registration is required by Thursday. For information and registration, call 888-327-2757. Select option 2 and refer to program number 1199. For information, call 510-544-3249 or e-mail kcolbert@ebparks.org.

Black Diamond: Fifty million years ago, the area that is now Black Diamond Mines Regional Preserve was an ocean. Naturalist Bob Kanagaki will take a virtual plunge to point out present-day evidence of that long-vanished sea during a free hike from 10 a.m. to noon Saturday. Meet Bob in the parking lot at the upper end of Somersville Road, 5 miles south of Highway 4 in Antioch. For information, call 888-327-2757, ext. 2750. Rain would cancel the hike.

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

---