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Tracking Chorus Frogs at Hirschman’s Pond

Chorus frogs (Pseudacris sierra)

Sometimes they’re called tree frogs, but even though they are capable climbers, due to having somewhat enlarged toe pads, they do not frequent trees.

Identifying features: Black or dark brown horizontal stripes extend from snout, through eyes, to shoulders, toe pads, webbed hind feet, coloration varies: green, brown, gray, tan, reddish, some with spots on back and legs. The male call is onomatopoeically represented as “kreck-ek”, and the sound of many calling at once suggests the common name “chorus” frog.

Citizen Scientist @ Work: Rich Wachs

Last spring, as a participant in SSI’s California Naturalist program, Rick Wachs chose the topic of amphibian monitoring for his capstone project. That initial project turned into something much bigger.

“I’ve always enjoyed seeing frogs while out hiking, from the Bay Area to the high Sierra, and I’ve often photographed them, but I never really focused on them,” says Rick. “I get out hiking a lot and early last year, while exploring along the Yuba, off Bowman Lake Road, a little chorus frog caught my eye. I took a photo and posted it on iNaturalist [an app for crowd-sourced phenology data]. That frog stuck with me somehow. So when the chance came up to work on SSI’s Amphibian Monitoring Project, I grabbed it.”

Rick’s work with 2016 Americorps scientist Alex Lincoln was part of a five-year project to monitor the health of local frog populations. He helped survey transects at Hirschman’s pond, observing egg masses and collecting data on chorus frogs.

In connection with his monitoring work with SSI, Rick went on several trips to survey foothill yellow-legged frogs. Those trips were led by Ryan Peek, from the Center for Watershed Science at UC Davis. Peek was gathering data for his doctoral research on conservation genetics and adaptation in the foothill yellow-legged frog, a species of special concern. “We were lucky to be able to work under Ryan’s permit and capture frogs, use calipers to take measurements, and swab for DNA samples. Ryan was an inspiring teacher,” Rick recalls. “I feel really fortunate to have participated on those trips. I learned a tremendous amount about the frogs, river and creek habitats and data collection.”

And he was hooked. “I was seeing things I’d never seen before and was really motivated to find out more.”

Hiking at Hirschman’s pond last November, the sound of frogs in the underbrush sparked the question: “What do frogs do in the winter?” And then in January and February when Rick began to see egg masses in the pond, he had his answer. They breed.

Egg Mass A: March 29, 2017

Rick began taking notes and pictures, tracking the egg masses. “There were distinct areas with a lot of activity, lots of egg masses were appearing. I followed their progress as rains came and raised water levels, and dry periods came and the water levels dropped. I was really curious to see how the eggs would fare.” Well, just a few weeks ago, Rick observed the first tadpoles swimming in those areas.

And now Rick has teamed up with SSI’s wildlife biologist Kristen Hein Strohm for a more formalized study of the chorus frog population at Hirschman’s pond. In addition to surveying transects through the ponds, they’re identifying specific egg masses and monitoring them, taking photos at designated intervals.

Armed with a new waterproof camera (purchased after dropping his first camera into the creek a few times), Rick is out at the pond several times a week, taking observations and teaching himself the tricks of underwater close-up photography. “In spite of the challenges

Egg Mass A: April 1, 2017

of getting clear, sharp images under water, with variables like the angle of the light or algae growing on the egg masses, if you study the photos closely, you can see the changes and track them. It’s amazing how quickly the eggs transform,” he enthuses.

One of the biggest surprises for Rick is the amount of time required to record and catalogue his data. Drawing on techniques he learned on Peek’s yellow-legged frog project, he uses the GPS data from his camera to map the sites of the masses and match them to the pictures he’s taken.

“I’ve always been an outdoors person and interested in the processes of the natural world. Over the past year, through the Cal Naturalist program and working on these projects, I’ve learned a bit about scientific research and methodologies,” says Rick. “It’s added another layer of interest and fascination for me. I’m able to see things that have been right under my nose in a new and richer way.”

Egg Mass A: April 4, 2017

Rick has some new skills in his citizen science tool kit these days, and through their use, has also been drawn to explore the scenery below the surface. He’s been submerging his new waterproof camera and taking many photos. “I’ve captured some really amazing images this way – including egg masses and snails and worms and tadpoles – a mélange of living and decaying material in the under-water world. There’s a real beauty in these images. I’m really intrigued by what I’m seeing.”

Rick says he doesn’t think he’s discovering anything new to science but these discoveries are new to him and that keeps him – armed with his camera and his curiosity – coming back to the pond.

Spoken like a true citizen scientist.