This is the third spring that the Friends of Herrontown Woods (FOHW) has helped frogs and salamanders safely cross Herrontown Road on their way to their breeding grounds in vernal pools. The work of the Princeton Salamander Crossing Brigade is documented in a blogpost on this site from last year, and in an article this week in the Town Topics. This year the Brigade was able to collaborate with Princeton's police department, which closed the road on one of the nights when the amphibians were on the move, dramatically reducing the customary carnage from road traffic down to zero. FOHW is hoping to collaborate similarly with the police department in the future.
Along with upcoming nature walks about amphibians during FOHW's Earthday celebration on April 13, I co-led an amphibian walk this past weekend, described below. Another walk I'm leading on April 5, through the Princeton Adult School, about plant life and forest ecology at Herrontown Woods will also touch on spring amphibian behavior and still has a few spots open.
The walk at Herrontown Woods this past Saturday delved into the lives of frogs and salamanders along the ridge. We were fortunate to have two members of the
Princeton Salamander Crossing Brigade with us. Inge Regan (second from left), who started the Brigade two years ago, is passionate about helping the frogs and salamanders safely migrate to their breeding grounds. This involves helping them avoid getting squashed by traffic when they cross the road on rainy nights in early spring.
Neuroscientist and Crossing Brigade member Lisa Boulanger is very knowledgeable about amphibians, and brought along a couple red-backed salamanders she had found under a log that morning. These small but numerous salamanders don't need a vernal pool to lay their eggs. Lisa brought along the two color phases: red-backed and lead-backed.
Our first stop was a small pond we had dug in the
Barden a couple years ago as part of a Zen Garden. I had placed a "refugia" in the bottom of the pond. An earthen pond in our piedmont clay will hold rainwater for days or even weeks, but ultimately the water seeps into the ground. Sinking a black plastic tub into the bottom of the minipond creates a refugia to sustain frogs and other water-loving creatures through droughts. This pond hosted adult green frogs and their young through last summer, and this spring during the walk, Lisa found a white glob of salamander eggs in the pond. Very flattering that the salamander community has found our little pond to be egg-worthy. (Info on mosquitoes and miniponds
in this post.)
Nearby, not far from the parking lot, we stopped by a small but mighty vernal pool that holds water longer than others in the woods. This little pond was created naturally. Years ago, a tree blew over, and where its rootball had been, the depression for a vernal pool was created. The clay under this pool is so dense that the water doesn't seep in, but instead remains to sustain hundreds of frog and salamander larvae until they can grow to maturity.
One curious observation we've made this year is that wood frog eggs, usually dominant in the vernal pools, are this year very few. No explanation for this scarcity as yet.
During the walk, Lisa was busily turning over logs in search of the most charismatic salamander in the woods, the spotted salamander. Finally, near a vernal pool deeper in the woods, she found one and showed it to all the participants.
Lisa has taken many photos of the salamanders crossing the road on rainy nights, including the one below. You can see why these wild creatures are much loved.
