We’re pleased to report a fifth native amphibian species has been detected on Mayne Island! Here’s an introduction to all five, including the newest member of our local amphibian family; the common ensatina!
Pacific chorus frog (Pseudacris regilla)
The Pacific chorus frog is the most often seen and heard amphibian on Mayne Island. It is well known for its loud spring chorus, and for showing up in the unlikeliest of places around the home and garden. When mature, adults are 2.5 cm to 5 cm in length. They can be recognized by the distinctive black mask running from nose to shoulder, and the large round toepads used for climbing. They range in colour from bright green to dark brown, occasionally reddish or even blue. Some individuals can change the hue and colour of their skin slowly over a period of days or weeks to match their surroundings. Interestingly, the chorus of this West Coast species is often used as the soundtrack in movies set in jungles or southern swamps.
Rough-skinned newt (Taricha granulosa)
One of the most easily recognizable and common amphibians on Mayne Island, the rough-skinned newt is less secretive than all but the Pacific chorus frog. These newts spend most of their time in forests and will travel large distances away from fresh water. They breed in natural wetlands and man-made ponds and have an aquatic larval stage that requires water until at least August. Rough-skinned newts are generalists in that they eat a wide variety of prey including many insects, slugs, tadpoles, and amphibian eggs, including those of their own species.
Rough-skinned newts contain the highest concentrations of the naturally occurring toxin tetrodotoxin of any known organism. This toxin provides the newt with an excellent defence from most predators. Toxicity levels are variable throughout the newt’s range and newts tested from Vancouver Island were not found to contain tetrodotoxin. The toxicity of rough-skinned newts on Mayne Island is not known at this time.
Red-legged frog (Rana aurora)
The red-legged frog is the other frog currently found on Mayne Island. They are much larger and less common than the Pacific chorus frog. Adults grow to a length of 3-10cm and can be identified by a longitudinal fold along each side of the body. Adults have distinctive red translucent undersides on their legs and lower abdomen. You’re unlikely to hear the red-legged frog calling, because they make their mating call underneath the water at a depth of one to five feet!
The red-legged frog is much more sensitive to habitat loss than the Pacific chorus frog because it has more specific habitat requirements and takes longer to reach maturity. Tadpoles do not complete metamorphosis until July; therefore, this species can only breed successfully in ponds that hold water until at least that time of year. The red-legged frog is suspected to have declined significantly in population within its primary range in BC, and for this reason is designated as a species of special concern in British Columbia.
Long-toed salamander (Ambystoma macrodactylum)
The long-toed salamander is a secretive animal that likes to hide in wet dark places in the forest and is rarely found far from water. Individuals can commonly be found burrowed into the forest floor or rotting logs to stay moist and warm. These fascinating animals can be identified by the green or yellow irregular stripe along their back and the noticeably longer fourth toe (second from the outside) on their back legs. Adults grow up to 16.5cm long including the tail, with a body length of up to 8.5cm.
Common ensatina (Ensatina eschscholtzii)
Detected for the first time on Mayne Island in late 2019 by Robert Anthony near the Georgina Point Lighthouse. Growing to 3-8cm in length, this reddish-brown terrestrial salamander is different from the rest of our amphibians in a couple of interesting ways. First, it’s the only one of our amphibian species that does not have an aquatic life stage. Rather, they lay their eggs underneath rotten logs and in old animal burrows in the forest, and newly born ensatinas look like miniature versions of their parents. Second, they do not have lungs, and breathe only through their skin.
To catch their favorite foods, they stick out their tongues. FYI, my kids are not allowed to act like ensatinas at the dinner table… They like to eat spiders, slugs, snails, beetles, worms, and other small creatures (the ensatina, not my kids that is). When ensatinas get together to mate, they do an intricate courtship dance involving a ‘tail walk’ and back rub.
What you can do to protect habitat for local amphibians
Rotting logs! A healthy natural forest is full of large logs in different states of decomposition. Rotting logs are where amphibians live in the wintertime, snuggling in under the warm blanket of decaying wood. In the case of the common ensatina, this is also where they lay and protect their eggs. So, when trees die or fall, leave them to decompose naturally so they will provide a place for amphibians to live.
For most of our amphibians, breeding habitat has increased in recent years as people have constructed ponds. However, many ponds do not provide the habitat features amphibians need to survive and reproduce. If amphibians lay their eggs in unsuitable ponds, the eggs or juvenile amphibians will die. The two most important features of ponds for amphibian breeding are gently sloped sides that allow for the growth of emergent vegetation, and proximity to a healthy forest habitat.
Habitat Connectivity – fresh water to forest floor
With the exception of the common ensatina, all of our amphibian species make seasonal migrations between their aquatic breeding habitats and the surrounding forest. With all the different human environments on Mayne island (cleared lawns, agricultural areas, roads, etc.), making the journey is more dangerous than ever, exposing amphibians to predators and vehicles. If you have a pond or natural wetland on your property, consider keeping a buffer of native vegetation that connects the pond or wetland to the surrounding forest.