Frog Docent Volunteer Program: Season Summary 2010

by Marisa Evans

Foothill yellow-legged frog (Rany boylii)

In 2005, MMWD started a docent program to raise awareness about the vulnerability of the foothill yellow-legged frog (Rana boylii) population at Little Carson Falls and to learn how visitor behavior affects the breeding success of the frogs, which are a federal and state species of “special concern” because of their declining numbers. Native to parts of the Mt. Tamalpais Watershed, the frogs breed and lay their eggs in and around the pools of the waterfalls from March through June.

After training with MMWD, individual docents make the trek to the falls (a two-mile hike off Bolinas Road from the Azalea Hill parking lot) and station themselves near the water for a five-hour shift. They greet visitors, explain why the pools are being protected, and provide scopes to view the frogs, egg masses, tadpoles and other critters using the water. They advise visitors to stay away from the pools, to keep their dogs on leash and out of the water, and to stay on the trail and behind railings to prevent disturbing the breeding frogs and their vulnerable egg masses and tadpoles. Leashed dogs are given dog biscuits as a thank you from the frogs.

Over the last five years, frog docents have contributed over 700 volunteer hours at Little Carson Falls and interacted with over 2,000 visitors. In 2010, docents made contact with 793 hikers and 80 dogs at the falls from mid-March through June. In one shift in late March, a docent reported 84 visitors!

Egg mass of foothill yellow-legged frog

There was plenty of positive feedback from members of the public, who were happy to learn more from the dedicated volunteers about the foothill yellow-legged frog and its breeding sanctuary at the gorgeous waterfalls in west Marin.

Watershed staff and visitors greatly appreciate the volunteers’ time commitment and enthusiasm to educate; their efforts make a huge impact in minimizing the impact of hikers’ visits. Our next docent training will be in February 2011. Visit our website for more information.

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For Foothill Yellow-legged Frogs, it’s that Time of Year

by Marisa Evans

Foothill Yellow-legged Frog (Rana boylii) at Little Carson Falls (Photo courtesy of Rob Ruiz)

Little Carson Falls is a very romantic place this time of year for the Foothill Yellow-legged Frog (Rana boylii). Native to parts of the Mt. Tamalpais Watershed, the frogs breed and lay their eggs in and around the pools of the waterfalls from March through June.

The Foothill Yellow-legged Frog is both a federal and state species of “special concern,” which means its population is declining. To help stop the decline and restore a healthy population within the watershed, MMWD trains volunteer frog docents to monitor the falls each spring when the eggs and tadpoles are at their most vulnerable.

In April, our 15 frog docents saw an average of seven frogs per shift. Surveys have recorded sightings of a juvenile frog, adult males, gravid females filled with eggs, and pairs in amplexus—part of the mating process in which the male clasps the female with his front legs in order to fertilize her eggs. The first egg mass spotted has been washed away, but on the brighter side two new egg masses have been observed.

Foothill Yellow-legged Frog pair in amplexus (Photo courtesy of Peter Denisevich)

In addition to the amorous frogs, docents have spotted salamanders, newts, snakes and mating lizards at the falls. Most importantly, they have engaged with more than 500 visitors so far! Our docents have spent their days educating Cub Scout troops on “frog safety” and cautioning hiking groups from as far as Sacramento that they are entering frog territory. One docent shared a glimpse of an egg mass through a scope with a couple who might otherwise have let their dog sip from the pool where the helpless eggs cling for dear life.

The frogs are small (1.5 – 3.0 inches long), greenish brown, and hard to spot, and the egg masses are no match against hiking boots and dog paws. If you visit the falls, you can help by keeping your distance from the pools, keeping dogs on leashes, and sharing this information with other hikers. Thank you for doing your part to protect this sensitive habitat, and thank you to our docents for being there to engage and educate visitors on behalf of the frogs!

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