As anticipated, the monarch butterflies have returned in good numbers to Ardenwood Historic Farm in Fremont for their annual winter fly-in, and lots of programs have been scheduled there for you to see the spectacle.

From 11 a.m. to noon every Saturday and Sunday from this weekend through Dec. 29, Ardenwood's interpretive staff will lead walks from the granary to the eucalyptus grove where the monarchs hang out. Each program starts with a slide show illustrating the butterflies' life cycle and the increasing threats to their survival.

There are also walks to the grove at 1:30 p.m. on all those same days. And there's a Spanish language program starting at the granary at 2 p.m. Dec. 22. Heavy rain would cancel the butterfly programs.

Ardenwood is located at 34600 Ardenwood Blvd., just north of Highway 84 in Fremont. For more information on park programs and fees, call 510-544-2797.

Tilden: From the spiritual to the practical, a couple of interesting free programs are planned this weekend at the Environmental Education Center in Tilden Nature Area in Berkeley.

The spiritual is from 2 to 4 p.m. Dec. 14 and again Dec. 21, when naturalist Anthony Fisher will host a program on "Practicing Awe in the Nature Area." It's about signs of the gathering winter.

Then from 2 to 3:30 p.m. Dec. 15, it's tick talk time under the guidance of interpretive student aide Morgan Rani Evans. Morgan will provide information about the little bloodsuckers, then lead a walk to identify the species found in the nature area. The center is located at the end of Tilden's Central Park Drive. To get there, park on Lone Oak Road off Central Park Drive and follow the signs to the center. For information, call 510-544-2233.

Coyote Hills: Flight in all its mystery will be the topic of a program from 2:30 to 4 p.m. Dec. 15 at Coyote Hills Regional Park in Fremont. Participants will try their hand at creating their own paper airplanes, helicopters and gliders, then take a stroll to the park's marsh to observe birds in flight, too.

The program is free of charge. Meet at the Coyote Hills Visitor Center. The park is at 8000 Patterson Ranch Road off Paseo Padre Parkway in Fremont. There's a $5 parking fee per vehicle. For more information, call 510-544-3220.

Coyote Hills also plans a winter solstice celebration, hosted by naturalist Kristina Parkison, from 4 to 5:30 p.m. Dec. 21, the shortest day of the year. The group will make solstice crowns and walk through the marsh while sharing stories of holiday traditions, then return to the visitor center for hot chocolate.

Designed for ages 10 and older, the program is free of charge, but registration is required. Call 888-327-2757, select option 2, and refer to program 4165.

Mission Peak march: The Wednesday Walkers, that informal but intrepid group of hikers led by naturalist Chris Garcia, will round out 2013 with its annual ascent to Mission Peak in Fremont. This is a strenuous 6-mile climb to the 2,517-foot summit. If you're up for it, meet at 9:30 a.m. in parking lot M at Ohlone College on Mission Boulevard. For information, call 510-544-3282.

Huckleberry Botanic: The park district's series of Saturday and Sunday strolls continues with a moderate, 2½-mile walk from 10 a.m. to noon Dec. 15 at Huckleberry Botanic Regional Preserve in the Oakland hills. The preserve is home to diverse plant life, including the rare and endangered pallid manzanita.

Meet at the preserve trailhead, which is on Skyline Boulevard about a mile south of the intersection with Grizzly Peak Boulevard. For information, call 510-544-3187.

Sibley Volcanic: Just north of Huckleberry on Skyline Boulevard is Sibley Volcanic Regional Preserve. Volunteers are needed there starting at 9 a.m. Dec. 15 for a work session to remove French broom, an invasive species that is crowding out native plants. Tools will be provided. For information, call 510-544-3112.

Black Diamond: Black Diamond Mines Regional Preserve in Antioch has two reptiles in residence: Ronda the rattler and Tyler the gopher snake. You can meet both of them, under safe conditions, during a free program from 10 to 11 a.m. Dec. 14 hosted by naturalist Bob Kanagaki. Bob will talk about how snakes weather the winter. His program is for ages 7 and older.

The location is Black Diamond Mines' park headquarters, which is in the cluster of buildings on the left just past the park entrance kiosk. Black Diamond Mines is located at the end of Somersville Road, 5 miles south of Highway 4 in Antioch. There's a parking fee of $5 per vehicle when the kiosk is attended.

Email Ned MacKay at nedmackay@comcast.net.