Every year, from November through January, monarch butterflies congregate at Ardenwood Historic Farm in Fremont, their black and orange wings creating an autumn leaf effect in the eucalyptus trees.

It has been described as an intergenerational relay race, during which the monarchs spend parts of their life cycle in habitats ranging from the western slopes of the Rockies to the Southern California coast.

At Ardenwood, naturalist Chris Garcia will host a free program from 2 to 3 p.m. Sunday, Nov. 10, to see if there are any early arrivals. Meet Chris at the Ardenwood granary for a short, guided walk to the grove where the monarchs hang out. There will be more monarch programs as the season continues.

Ardenwood is located at 34600 Ardenwood Blvd., just north of Highway 84 in Fremont. Entry fee is $6 for adults 18 and older, $3 for seniors 62 and older, $2 for children ages 4-17, and free for ages 3 and younger. Parking is free. For information, call 888-327-2757, ext. 2797.

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    Coyote Hills Regional Park, which is almost next door to Ardenwood, will hold an open house from 1 to 3 p.m. Saturday, Nov. 9 and Dec. 21, and from 10 a.m. to noon and 1 to 3:30 p.m. Saturday, Dec. 14, all at the park visitor center.

    The open houses are a chance to meet the visitor center's reptiles in residence, hear some nature stories, and work on nature crafts. All ages are welcome.

    Coyote Hills is at 8000 Patterson Ranch Road off Paseo Padre Parkway north of Highway 84. For information, call 888-327-2757, ext. 3220.

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    Three nature safaris are on the calendar at the Tilden Nature Area in Berkeley.

    The first is a ramble from 1:30 to 3 p.m. Saturday, Nov. 9, led by naturalist Trail Gail Broesder. Walk with her to the lake and look for signs of wildlife.

    And if you don't know what benthic macroinvertebrates are, join naturalist Trent Pearce on a trek from 10 to 11:30 a.m. Sunday, Nov. 10, to find some in Wildcat Creek. Wear shoes that can get muddy.

    If you're up for something more strenuous, Trail Gail will lead a six-mile hike from Wildcat Creek to the ridge top and back, including Lake Anza, from 9 a.m. to 1 p.m. Friday, Nov. 15. It's for ages 12 and older; bring a snack to share.

    All three programs are free. For the first two, meet at Tilden's Environmental Education Center. It's at the north end of Central Park Drive. But because of ongoing construction, the best way to get there is to park at the end of Lone Oak Road off Central Park Drive, then follow the signs to walk to the center.

    For Gail's six-miler, meet at the Lone Oak picnic area on Lone Oak Road. For information, call 510-544-2233.

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    From the earth below to the skies above, the staff at Black Diamond Mines in Antioch will reveal the park's natural history secrets during a couple of programs in the coming week.

    Naturalist Bob Kanagaki will lead the underground expedition, from 9:30 to 11 a.m. Saturday, Nov. 16. The group will look at rocks and trace fossil remnants of the shallow sea that covered the area 50 million years ago.

    Bob's program is for ages 7 and older. There's a $5 fee per person and registration is required. To register, call 888-327-2757. Select option 2 and refer to program number 4059.

    Wild turkeys and turkey vultures will be the quarry during a hike from 9 to 11 a.m. Sunday, Nov. 17, at Black Diamond, led by naturalist Ashley Elliott. The program is for ages 7 and older. It's free; meet at the uppermost parking area at the end of Somersville Road, five miles south of Highway 4.

    Black Diamond Mines' Greathouse Visitor Center is open from 10 a.m. to 4:30 p.m. on weekends through the end of November. Likewise, tours of the park's Hazel-Atlas silica sand mine are conducted at various times on weekends through November.

    The underground tours are open to visitors ages 7 and older, and there's a $5 fee per person. All ages are welcome at the visitor center and entry is free. Both the mine and the center close from December through February.

    For more information, call 888-327-2757, ext. 2750.

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    As a salute to our servicemen and women, active duty, retired, reserve and veteran military personnel will get free parking and entrance on Veterans Day, Monday, Nov. 11, at all East Bay Regional parks.

    Military members and veterans of all service branches are invited to enjoy all park district facilities in Contra Costa and Alameda counties.

    This benefit to active, reserve, and retired military personnel is new in 2013, approved by the board of directors as part of the consolidated fee schedule.

    Benefits apply to the individual military person, but not the entire family, except when parking, when there is a military affiliated person aboard. Parking is charged per vehicle.

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