Hey everyone, it’s Jenn Barden. I’m the Herpetofauna Projects Coordinator, which means I run all of our frog and toad programs here at the FVC. I wanted to share an awesome experience that Joelle and I had this past June 2022.
Get your waders on and strap in – we’re flying to the Skagit!
Did you know that there are two species of frog in BC that look nearly identical but are not found in the same wetlands? The two Spotted Frogs, Oregon Spotted Frog and Columbia Spotted Frog, are so similar that only careful measurements or DNA analysis can tell them apart!
These frogs live in different areas of BC: the endangered Oregon Spotted Frog lives west of the Cascade mountains, and the Columbia Spotted Frog lives in the east. This means when we work in the Fraser Valley, we always find Oregon Spotted Frogs.
The mystery of the Skagit Valley Regional Park began just a few years ago when eDNA studies reveal BOTH species were present in the park. This had never been found before in Canada! Earlier this year, the FVC received a contract from the Skagit Environmental Endowment Commission to further investigate this amazing discovery.
Our mission: to catch frogs, sample their DNA, and take photos of the habitat at two locations in the park.
The extreme flood event in November 2021 washed out huge sections of the Silver Skagit Road leading to the park. The only way into the park was by helicopter!
Before setting out on this adventure we did some desktop mapping investigations to help us decide where we needed to survey to find the Spotted Frogs. We were curious: after the flooding, would the landscape have changed? What about the course of the river? Had the flooding altered the landscape enough that we wouldn’t be able to access areas we wanted to survey?
We took a helicopter into the park. Our first survey site was the northern tip of Ross Lake, so we were dropped off at the Ross Lake campground. We set up camp, hung our food from a tree to avoid attracting bears, and got to work.
When we got to the lake the water levels were lower than expected and the river did seem to divert differently than the maps suggested. However, we were able to cross all parts of the river and get to the areas we were interested in.
We also noticed a lot of woody debris, particularly large trees that had clearly been moved by water when the levels were higher.
Our Ross Lake fieldwork was conducted over 2 days, and on the first day we were able to survey part of the eastern side, walking through a large grassy area where I found a Common Gartersnake. We also saw some frog habitat and found a Northern Pacific Treefrog, our first frog of the trip!
Towards the end of our first survey day, we focused on figuring out how to cross the last and largest section river channel that we had to cross. We planned out our second day over dinner – our goal would be to get over that last river channel where we hoped there would be more frog habitat, and frogs. At the end of our first day we still had not seen a single Spotted Frog. But that night we could hear a whole army of tree frogs ribbitting, so we were hopeful.
We woke up early on the second day determined to get across the channel to more survey sites. After much debate about how to cross the last channel of the river, we were able to safely get across and continue our search. At first, we found several small, shallow pools of water with the potential to be frog habitat, but no frogs in them. Then, we found our first semi-deep pool of water and looking right at us as we approached the pool were two big eyes – our first Western Toad! We saw a few adult toads but weren’t able to catch any.
We then found Pacific Treefrog egg masses in a small stream. This was exciting since these frogs breed as early as March in the Fraser Valley lowlands. Even with the higher elevation and lower temperatures in the park, we weren’t expecting to see egg masses so late in the year.
Although these were exciting finds, the best part was finding what we went all the way there for – Spotted Frogs! We caught a total of three juvenile Spotted Frogs and saw a few others hopping around. Two were found in a small pool of water, and one in the same stream where we saw the Pacific Treefrog egg masses. Since we couldn’t tell which species of Spotted Frog they were just by looking at them, I took DNA samples (by swabbing their skin) and measurements. These samples will be sent to a lab so we can find out if they are Oregon or Columbia Spotted Frogs. We will have the results in a few months.
Ross Lake is large, even just the northern tip on the Canadian side, so we had lots of ground to cover! After checking out all the ponds and streams we could get to in the limited time we had, we headed back to camp and were picked up by the helicopter just as it started to rain.
One week later, we headed out to our second site, a wetland just north of Ross Lake. This time, the helicopter touched down in a meadow and we had to bush-wack through the forest to get to the wetland. Without any paddle boards, the walk to get to the site was much easier than at Ross Lake, but when we got to the wetland the water was a lot deeper than expected.
We walked along the edges of the wetland, assessing the habitat, taking notes about the vegetation, and finding frogs! We saw so many Western Toads at this site, of all life stages. We found adults, juveniles, and even a tadpole. The toads at this site also seemed a little further along development-wise when we compared them to their Ross Lake counterparts.
Just as we were about to leave our second site, disappointed that we hadn’t found any Spotted Frogs, I caught sight of a juvenile just out of arms reach… but the little guy got away. We waited for the juvenile to pop his head back up and searched around for more Spotted Frogs in the same area, and eventually came across an adult! She was successfully caught, processed, and had a mini photo shoot before being released back into the wetland.
Despite wanting to stay and find as many frogs as possible, it was time for us to head back home.
We saw Spotted Frogs, Pacific Treefrogs and Western Toads… and we didn’t see any bears. Sounds like a successful trip to us! Now we are back in the office dreaming about fieldwork in the beautiful Skagit Valley and making plans for more fieldwork next spring, this time searching for Spotted Frog egg masses. We are also looking forward to getting our DNA results back from the lab for our four Spotted Frog DNA samples. Despite the challenges surveying this area we had so much fun and can’t wait to get back out there and see what we can find. Stay tuned for our next update!
Special thanks to the Skagit Environmental Endowment Commission for funding this work.
