Ken Bevis, DNR Stewardship Wildlife Biologist
Ah, spring! There are so many sights and sounds to enjoy, from new growth in the woods to the calls of courting wildlife. One of the surest signs of spring is the mating calls of frogs and toads. You’ve heard them if you have ever lived near a small pond, a spring seep, or a side channel separated from a creek that’s between 6 inches and 3 feet deep and stays wet until at least early summer. Trilling and croaking, looking for love.
But how do you know which frog or toad is making all that noise? Go look – it’s fun for kids and adults! With an identification book in hand, walk slowly and quietly along the edge of the water, but be careful – when they sense a big looming presence, they usually skitter to cover and stop calling. If it’s nighttime, a flashlight will help you spot their eyes, then you can creep up to see them. If it’s daytime, binoculars with close focus can help you spot them. If you don’t see the critters themselves, you may see their eggs, which are much harder to identify the critter from but a sure sign they’re breeding.
Native frogs and toads can start breeding as early as February in western Washington and April on the eastern side of the state. Each species lays their eggs in a different manner. All the eggs are gelatinous, but some are large globs attached to vegetation, others can be free floating blobs, or even stretched out on the bottom of the shallows in strings. When the eggs hatch after a few weeks, larvae or tadpoles can be seen in the water until late spring or early summer. The tadpoles slowly turn into miniatures of their parents – first growing their back legs, then their front, and finally losing their tails and moving to their adult habitat.
Some salamanders also use small ponds, seeps, or side channels for breeding and their egg masses can be similar in appearance to frogs and toads. Larval salamanders live near the bottom, with gills protruding from behind their head, and look like tiny legged lizards. Many species leave the water for their adult lives and can move surprising distances from the breeding waters, spending summer and winter hiding underground or within and beneath rotting leaves and wood.
Although soils, vegetation, moisture and altitude all have an influence on the kind of amphibians you may find, there are a few that are common to both sides of the Cascades including the Pacific chorus frog (tree frog) (Pseudacris regilla), the long-toed salamander (Ambystoma macrodactlyum), and the western toad (Anaxyrus boreas). As adults, these animals will move considerable distances from water, hiding underground in small mammal tunnels and under rotting wood. Some species can tolerate surprisingly dry conditions too. The western toad has skin that is less porous than many frogs, while the Pacific chorus frog has a waxy skin coating that helps them survive dry conditions. Western toads are generally brown to gray with lumpy or warty skin and chorus frogs range in color from golden, to green to gray. On the west side of the Cascades, chorus frogs can be active all year and you can hear their kr-r-r-ek on rainy winter nights or find them lurking in the flower pots on the deck. Long-toed salamanders are dark gray-green and about 4 inches in length with a yellowish stripe down their back.
Providing and protecting these habitats on your forestland can be easy and rewarding. First, locate the places where water accumulates in the spring. Does it dry out? Is it sheltered with vegetation? Are there livestock or pets affecting it? Are there fish? Is there a habitat connection to a wildly vegetated place where the adults could spend the summer and winter?
Good amphibian breeding habitats will have overhanging deciduous vegetation, which allows the early spring sun to warm the water before the leaves appear and later will provide shade and cover from predators. There will be emergent plants in the water and some woody material lying in the water, like logs or tree branches. Livestock and pets can trample the shallow edges of small ponds and literally crush egg masses, not to mention removing the sheltering vegetation. Fish are predators on many amphibians, particularly juveniles, and will limit the presence of some species. And when the little amphibians make it to adulthood, and need to get out to the woodland, they need a pathway to get there! Maintain or create a corridor with down wood and dense vegetation to help the frogs and salamanders reach their summer habitats. What can you do to improve the habitat? Toss some branches into the edge of the water. Plant some overhanging vegetation. Keep pets and livestock out of the pond. Maintain rotten logs in the forest and near the water. Listen to the music on a spring night.
We can help our native amphibians with attention to these small habitat features that may not seem like much to us, but to a tiny frog or salamander, they can mean life or death.
Amphibians are amazing and ancient creatures with a myriad of adaptations to survival. A particularly good reference for identifying species is “Amphibians of Oregon, Washington and British Columbia: a field identification guide” (Corkran and Thoms, 1996 Lone Pine Press). Some ideas for enhancing frog habitat can be found on the Washington Department of Fish and Wildlife Living with Wildlife web site and the book “Landscaping for Wildlife in the Pacific Northwest” (Link 1999) also has a wealth of information. Or contact Ken Bevis the DNR Stewardship Wildlife Biologist (Ken.Bevis@dnr.wa.gov) for ideas on how to help native amphibians on your woodland.