Herp Update: Herp Activity, Saturated-soil Searches, Gray Treefrogs – November 21, 2024
Herp Activity Likely Tonight
The forecast looks perfect for some fall amphibian migration tonight after dark. I hope some of you can get out and report what you find. I predict primarily Blue-spotted Salamanders, Eastern Red-backed Salamanders, Four-toed Salamanders, and perhaps a few Spotted Salamanders and frogs. Amphibians have not had many rainy nights to move this fall. I have been getting reports of a few Spotted Salamanders moving (barely) during the day.
It would be really great to document some previously unknown locations for Four-toed Salamanders. They are most likely to be coming out of forested swamps, tussock swamps, or other wetlands with structure that extends above the water line. They need those raised areas for depositing their eggs. From these wetlands they will be heading uphill into deciduous woodlands where they will follow cracks, crevices, and small mammal tunnels below the frost line. Remember that they are very similar in appearance to Eastern Red-backed Salamanders, but they are much easier to catch and pick up (slower and less wiggly) and their bright white undersides with black spots are diagnostic (see the photo below taken by Kiley Briggs).
Monitoring has Ended for the Year but Saturated-soil Searches Continue
The Herp Atlas in cooperation with the Colby Hill Ecological Project, has woodland-amphibian monitoring transects in Lincoln. We monitor a series of 46 cover boards every-other fall. We check them once a week from the beginning of September until the numbers of salamanders found declines significantly. This year they dropped from 33 Eastern Red-backeds under the salamander covers in early September, to only two under the covers in early November. So, we stopped our monitoring for the year. Eastern Red-backeds move deeper into the soil as the cold weather arrives but they return to the surface during warm wet nights. I suspect some will return to the surface in tonight’s (Thursday’s) rain.
Since we no longer needed to monitor the cover boards and being unwilling to give up field work for the season, we focused our survey efforts on our saturated-soil salamanders. Ground water-fed streams and seepage areas do not freeze entirely during the winter, so they are safe places for Spring Salamanders, Northern Two-lined Salamanders, and Northern Dusky Salamanders to spend the winter. By turning cover objects either in or along the edges of permanent, small, mountain streams, we can find and document these species all winter long. It certainly becomes more difficult and uncomfortable searching for them when the snow arrives and rocks are covered with ice, but until then, we can still find and document them within a few hours. Over the last few weeks, we have updated old reports of these species in Andover, Landgrove, Ludlow, Mendon, Mount Tabor, Pawlet, Sandgate, Shaftsbury, and Weston. Occasionally we turn up a Green Frog that is overwintering under a rock in the streams along with the salamanders.
Gray Treefrogs set a New Record for Late-season Calling
Retired Fish and Wildlife Nongame-biologist Steve Parren reported a single Gray Treefrog calling in Monkton on November 19. This was the latest reported calling for Gray Treefrogs in Vermont. It held that record for almost 24 hours. The next day Steven Yaskell reported another Gray Treefrog calling in Mount Holly. Prior to these two reports, the latest report of calling Gray Treefrogs was October 21, 2007. However, the 2007 report was from a day with the temperature over 70 F. The Parren and Yaskell reports were from days with the temperatures only in the low 40’s F.
Where do Gray Treefrogs Spend the Winter?
Since Gray Treefrogs are freeze-tolerant, they don’t need to get below the frost line to survive the winter. Still, it is unclear where most of them actually do spend the winter. When I was working at Middlebury College, a February storm brought down a branch from a large oak tree. Along with the branch came a Gray Treefrog that was spending the winter in some crevice in that branch. Until then, I had assumed that Gray Treefrogs overwintered in the leaf litter like Wood Frogs and Spring Peepers. I also have received at least one report of someone finding a Gray Treefrog during the early spring in a rain gutter that had filled with leaves. This raised the question, where do most of the Gray Treefrogs spend the winter? Is it up in trees or on the ground in the leaf litter? Like all amphibians, Gray Treefrogs need to preserve their body moisture. So, on hot dry days in the summer, and all winter long, they tuck into tight spaces to minimize the amount of their skin exposed to the air. Are most of them overwintering while tucked into cracks and crevices in the trees, are they in the leaf litter, or are they overwintering in both places? UVM graduate student Matt Gorton has some small radio transmitters on Gray Treefrogs (think small backpacks) this fall in hopes of answering that question this winter. I anxiously await hearing his results.
The Gray Treefrog photo below was taken by Toby Alexander.
