About the Treefrogs of Paradise
Amazing, really, where a glass of wine and an evening of conversation over a frog chorus will take you. Don and Sharon Cocheba started thinking about my fascination with blackbird songs around our marshes, and decided maybe Diane and I needed to expand our critter-music horizons a bit. Thus, one evening last week we found ourselves on their deck, in the foothills of Paradise, wine in hand, being serenaded by an army of frogs.
Somewhere in our after-dark conversations – among a fair number of catchups about Africa, families, current and former colleagues, and the state of academia these days – was a lively discussion of just which frogs we were experiencing. Whatever brand they were, the boys had a loud message to convey. No matter what we discussed, or how loud we discussed it, the frogs just didn’t care. Turns out that the Cocheba corner of Paradise holds at least two, maybe three, different frogs.
Over the years, as their habitat developed, most observations turned up Columbia spotted frogs (Rana luteiventris), and Pacific treefrogs (Pseudacris regilla), with the possibility of a few of the widely scattered and increasingly rare Northern leopard frog (Rana pipiens).
The leopard frog is the largest of the three, at about four inches body length. Its back and sides have large dark spots with light borders. Its mating vocals last a few seconds and are several low-pitched grunts and snorts (likened to the putt-putt-putt or a small boat motor).
The spotted frog gets to about three inches in length, varying from light to dark brown or olive, with dark spots and distinctive upturned yellow eyes. Its call is very faint and rapid, with a couple dozen low hollow notes (likened to the sound of a distant woodpecker on hardwood).
The frogs serenading us were male Pacific treefrogs – aka The Chorus Frog. At two inches body length, this is the smallest of our frogs (females slightly larger than males, but both smaller than a chicken egg). Treefrogs are the most common, most often heard, and undoubtedly the most fascinating of Washington’s frogs.
As Science Education Committee Chair for the Reecer Creek Rod, Gun, Working Dog and Outdoor Think Tank Benevolent Association, I am duty bound to pass along what follows.
Frogs are amphibians, of course (Greek roots amphi, “both,” and bios, “life”). Female treefrogs lay hundreds of eggs, as the male fertilizes them, in golf- to baseball-size clusters enveloped in a “jelly” that swells up in water, and attached to sticks or grass under water. Frogs start their lives totally aquatic, with gills and a tail fin; tadpole stage. By six weeks, legs develop, the tail and gills are absorbed, and they are half-inch long, air-breathing juvenile frogs climbing onto land.
The Pacific treefrog has a black stripe “mask” from the tip of its snout to its shoulder. It varies in color from bronze to gray to tan to pale lime green – some will be a solid color while others will be richly patterned – and individuals will change color with air temperature and humidity.
Our treefrog ranges from British Columbia to the tip of Baja California, and east into Montana and Nevada. Habitat will have suitable breeding water, which generally means ponds somewhere along the edges of lakes and streams. Outside breeding times, they largely inhabit surrounding land area (pastures, woodlands, gardens and so forth).
Treefrog’s diet is mostly a wide variety of arthopods (insects, spiders and small crustaceans). In turn, eggs, tadpoles and juveniles are enjoyed by caddisfly larvae, predaceous diving beetles, giant water bugs, fish, birds and garter snakes. Raccoons, foxes, river otters, skunks, snakes, hawks, herons, owls, bullfrogs, cats, children, lawn mowers, and vehicles all take a toll. Most treefrogs die in the water stages; those reaching adulthood live about two years.
Here are several interesting tidbits you can slip into any conversation about treefrogs. A group is an “army.”. They secrete a waxy skin coating (described as Velcro-like), allowing them to remain moist far from water. Sticky pads on their long, largely un-webbed, toes allow them to climb with great agility (thus, “tree frog”), but they usually stay near the ground. Since 2007, the Pacific treefrog is the state frog of Washington. Get this: while most frogs bury themselves in mud and go into a torpid, hibernation-like, state to survive winter, treefrogs crawl under leaf or other litter for their dormant season, and may freeze solid – yet still return to life in spring.
Oh, yes. That glorious froggy serenade. The call of the male – to attract females – is far louder than a two-inch critter ought to be able to manage. The two-part kreck-ek, or a ribbit, repeated, gets other males joining in, making a sound heard a half-mile or more away. Males call mainly in the evening. (Don arranged for his to start at 9 p.m.) Turns out we are all quite familiar with this call: when Hollywood moviemakers once wanted set a feeling of an outdoor night, they recorded treefrogs. That “ribbit-ribbit” call of the treefrog is now the stereotypical, standard, frog call, even in movies set in regions without treefrogs. You gotta love the Chorus Frog!
(Special thanks to Jason Irwin, Professor of Biology, and amphibian pro, at Central Washington University for sharing some of his fascinating treefrog research for this week’s effort. You can learn more at naturemappingfoundation.org/natmap/facts/pacific_treefrog_712.html (Washington Nature Mapping Program) and Washington Fish and Wildlife’s “Living with Wildlife,” at wdfw.wa.gov/living/frogs.html.)
