FrogWatch 2020 Observations in the Hills
By Don Danila and Susan Gonzalez
Last summer we reported on our 2018 and 2019 FrogWatch observations in the Preserve. FrogWatch is a nationally recognized program that provides valuable information on the distribution and abundance of frogs and toads in the U.S. We are both trained in FrogWatch sampling protocols recognizing the calls of all 11 species of frogs and toads found in Connecticut.
The Yale-Peabody Museum of Natural History website provides information on our state’s frogs and toads, as well as short sound clips of their calls at:
Protocols call for 3-minute observations to be made beginning 0.5 hour after sunset and recording all species heard and the intensity of their calls.
This year we made observations from March through July at three sites in the Preserve:
These sites are found within the southern portion of the Preserve. Based on past experience, the WL sites were not sampled in July 2020, after no calls were heard there in June and no significant precipitation occurred in July that might have attracted frogs or toads.
During the previous two years, we did not hear any wood frogs calling during our nightly observations, even though many people could hear them during hikes in daylight hours. Also, we heard no toads calling even though we knew that the American toad is found in the Preserve.
We were pleased to finally hear wood frogs calling at the WL stations during March. Their reproduction was confirmed by observing egg masses in WL #24 on the following day
Many spring peepers were heard at Clark Pond, but this species had not yet appeared at the WL sites. April was disappointing in that no frogs were heard at Clark Pond and only a few spring peepers were calling at the WL sites. The April observation took place several days after some rainfall, but the cool night air temperature may have inhibited frog activity. In May, after some rain, we finally heard a few American toads calling at both WL sites. Spring peepers were very numerous and loudly calling at all sites. We also heard a few bullfrogs in Clark Pond. As noted earlier, nothing was heard at the WL stations in June, but there were green frogs as well as a few bullfrogs and gray tree frogs at Clark Pond. We finished up in July at Clark Pond, where only green frogs were heard.
This year’s sampling showed how variable frog occurrence can be over time. We heard fewer American bullfrogs in Clark Pond this year than in 2018 and 2019. The intensity of gray tree frogs was much less in June 2020 than in June of the previous two years, when full overlapping choruses were noted. We hope to continue to document the frogs and toads in the preserve next year.