Amphibians & Reptiles


Northwestern garter snake

While Opal Creek’s climate is generally too cold for reptiles, there are a few species found here, species that are widely distributed in western North America and can be found at the northern limits of reptile distribution in general. These include the northwestern garter snake (Thamnophis ordinoides) and western fence lizard (Sceloporus occidentalis). These species feed on insects and other invertebrates, as well as small mammals and amphibians. Because reptiles are ectothermic (cold-blooded), they hibernate for much of the year, only emerging when the temperature is high enough to support activity.

Look for reptiles on sunny rocks and roadbeds in the spring and summer. Lizards can be found in abundance at the Starvation Mill site in the meadow past Jawbone Flats. Lizards and snakes are food for osprey and other birds of prey in the Opal Creek watershed, in addition to mammals such as foxes, bobcats, and raccoon.

Western Red-backed Salamander, Opal Creek Ancient Forest Center

Western Red-Backed Salamander, copyright Steven Johnson 2013.

Amphibians, on the other hand, are found in diverse abundance, and rely on moisture and clean water for their survival. These animals are both aquatic and terrestrial during different times of their lives. Amphibians are on the decline globally and the species of the Northwest are no exception. While no single factor has been identified as the sole cause, ecologists now think that a variety of factors can be blamed for the population crash, including loss of habitat, ozone depletion, increased instances of fungal and parasitic infection, and increased water temperature from global climate change and deforestation. Many species that are reliant on fast-moving cold streams are especially threatened due to thermal pollution and a loss of habitat. Two such species are found in Opal Creek in relative abundance: the Tailed Frog (Ascaphus truei) and the Pacific Giant Salamander (Dicamptodon tenebrosus).

Amphibians play an integral role in the Opal Creek food chain. They are prey for birds, river otters, and other predators, and in turn prey on many invertebrates during both their aquatic and terrestrial phases. Terrestrial amphibians can be found in and under moist logs; in water such as ephemeral ponds, puddles, and streams; and in trees or moist shrubbery.

Interested in learning more about Amphibians?

Check out our weekend family workshop Amphibian Adventure, taught each spring. Click here to read a review of this workshop on PDX Kids Calendar’s website.

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