Among other festivities, East Bay Regional Park District is celebrating its 80th birthday by offering Free Fridays in the parks.

Starting April 18, fees will be waived for a variety of park services every third Friday of each month for the rest of the year. On those free Fridays, you won't have to pay for parking, boat launching or entry for horses and dogs. And you won't have to pay for swimming, district fishing permits or entry to Ardenwood Historic Farm in Fremont.

Boat launchers will still have to pay for the required invasive mussel inspection. Anglers will still have to possess a California state fishing license, for which there's a fee. And there will still be fees for camping and for group picnic reservations.

Free Fridays are the park district's way of thanking the public for 80 years of support. A grass-roots movement provided the political momentum for establishment of the district back in 1934, and public support has been key to the district's successes ever since.

BIG BREAK: With springtime comes a florescence of activities in the regional parks. Let's take a lap around the district to see what's in store:

The animals that roam the parklands leave an abundance of clues to their identity. You can learn how to be a nature detective during a free program from 2 to 3 p.m. Sunday at Big Break Regional Shoreline in Oakley. Cast tracks in plaster, examine chewed branches and listen for birdcalls to figure out what's out there in the wilds. Big Break is located at 69 Big Break Road off Main Street. For information, call 888-327-2757, ext. 3050.

HILLY HIKE: At Black Diamond Mines Regional Preserve in Antioch, naturalist Ashley Elliott will lead a hilly 6-mile loop hike from 9 a.m. to 2 p.m. Sunday. Stops along the way will include historic Rose Hill Cemetery, the Nortonville town site, and Jim's Place, an underground chamber of unknown origin and use. No one seems to know who Jim was, but the room bears his name.

The hike is free, though Black Diamond Mines has a parking fee of $5 per vehicle when the kiosk is attended. Bring water and lunch; meet Ashley at the uppermost parking lot at the end of Somersville Road, five miles south of Highway 4. For information, call 888-327-2757, ext. 2750.

BRIONES PEAK: After Ashley's hike, if you're up for another hilly 6-miler, join naturalist Chris Garcia and the Wednesday Walkers at 9:30 a.m. next week for a strenuous climb to Briones Peak at Briones Regional Park near Orinda. The reward is panoramic views and abundant wildflowers.

Meet at the park's Bear Creek Staging Area, which is on Bear Creek Road about 5 miles east of San Pablo Dam Road in Orinda. For information, call 510-544-3282 or e-mail cgarcia@ebparks.org.

now hare this: What are lagomorphs? Here are some hints: they're furry, have long slender ears, move mainly by hopping and on Easter they are said to deliver colorful eggs, both hard-boiled and chocolate.

You can meet some of them at a lawn get-together hosted by interpretive student aide Sabrina Eugster from 2 to 3 p.m. Sunday at the Environmental Education Center at Tilden Nature Area in Berkeley. The program includes a story or two and a special snack for the lagomorphs. The center is located at the north end of Tilden's Central Park Drive. To get there you have to park at the end of Lone Oak Road off Central Park Drive, then follow the signs on foot. For information, call 510-544-2233.

CRAB COVE: There's a Family Nature Fun Hour scheduled from 2 to 3 p.m. every Saturday and Sunday at Crab Cove Visitor Center in Alameda. This weekend, the group will dissect squid to learn about these fascinating creatures of the deep. After that it's fish feeding time from 3 to 3:30 p.m. at the center's large aquarium. Crab Cove is at 1252 McKay Avenue off Central Avenue. For information, call 510-544-3187.

Garin Regional: Dogs will have their day during a "Canine Capers" program from 9 to 11 a.m. Saturday at Garin Regional Park in Hayward, led by naturalist Kristina Parkison. Homemade snacks will be provided for all good (and spirited) dogs.

Humans attending should be 8 and older, please. Canine Capers is free, but registration is required. To register, call 888-327-2757. Select option 2 and refer to program 5269.

Coyote Hills: Snakes will be the stars of a program Sunday from 10 a.m. to noon and again from 1:30 to 3:30 p.m. in the visitor center at Coyote Hills Regional Park in Fremont.

Naturalist Dino Labiste will talk about how snakes have adapted to their environment and share a bit of snake folklore. The group will make snake spiral crafts to take home. Coyote Hills is at the bay end of Patterson Ranch Road off Paseo Padre Parkway. The snake program is free, but Coyote Hills charges a parking fee of $5 per vehicle. For more information, call 510-544-3220.

and more: Looking ahead, there are lots of special events on the regional parks calendar. To mention a few, the Tartan Day Scottish Fair is at Ardenwood Historic Farm in Fremont on April 5, Sunol Wilderness will have its Spring Wildflower Festival on April 12, and the Botanic Garden plant sale at Tilden Regional Park is on April 19. More about these and other activities in future columns.

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