An inventory carried out in 2000 revealed twelve different amphibian species at Weir Farm National Historic Site. The frogs included Wood frog (Rana sylvatica), Pickerel frog (Rana palustris), American bullfrog (Rana catesbeiana), Spring Peeper (Pseudacris crucifer), Fowler’s toad (Bufo fowleri), and Gray treefrog (Hyla versicolor). The salamanders included Spotted salamander (Ambystoma maculatum), Eastern red-backed salamander (Plethodon cinereus), Red-spotted Newt (Notophthalmus v. viridescens), Northern two-lined salamander (Eurycea bislineata), and Marbled salamander (Ambystoma opacum). They can all be found in wetland pools, along seeps, springs, and streams, in the woods, or on the hiking trails.

Amphibians are known for their dual ability to live in water or on land. Red-Spotted Newts are no different. Red-Spotted Newts, also known as Eastern Newts or Red Efts, are a common site along the park’s hiking trails, particularly following a rain. They spend their youth in the water, then on land for two to seven years, before returning to the water to mature into aquatic adults. As aquatic adults they are water bound and no longer able to return to land. They can often be seen moving under the ice in the winter, as they stay active year round.