According to Amphiaweb.com, Pacific tree frogs (Pseudacris regilla) are usually the most common frog species where they occur in the Pacific Northwest. This summer in particular, I have observed them nearly everywhere I go on the property, clinging to leaves, logs, walls, and windows, leaping frantically from the mower blades and dangling from  my raspberry vines. It seems to be a takeover of sorts.

They breed in the wetland I refer to as the lake, which consistently fills up each winter, then mostly dries out in the summer as feeder streams bring sediment and vegetation gradually builds up. Apparently they enjoy ephemeral wetlands as they like calm, shallow waters. They usually begin their breeding chorus in February when sheer numbers create a wall of noise within which individual frogs are nearly undetectable.
During the summer, they leave aquatic habitats and migrate upland where they can be found nearly everywhere. Meanwhile, their breeding songs have been reduced to occasional dry ‘craaaaks’, as though to locate each other during their wanderings.

They can be found in a wide range of unexpected places. A little frog I named ‘Sir Splat’ liked to tuck up at the top of an outside door I use frequently. As I opened it, it would fall to the tile floor with a moist ‘splat’, then crawl away as though the equivalent of a human jump off of the Brooklyn Bridge had meant nothing to it.

Before I noticed the frog, I had seen small black droppings on the door and around the recessed knob. I blamed the cats for failing to catch house mice, wondering nevertheless how a mouse could scale a vertical surface and leave pellets. Turns out it was frog scat I was seeing, a substance that comes in an array of sizes, the largest of which reveals the cast-off chitin of their insectivorous diet.

Other frogs inhabit window sills, where they press into corners with feet drawn up under them to conserve water.

Curiously, even during hot, sunny days, I would find the on the tops of leaves several feet above ground, exposed but pressed closely to the surface to stay moist.

Others preferred hiding under the bark of logs I intended to move. One log yielded three little green faces with black stripes peeping out at me as I carefully replaced the loose bark and left them alone. Mowing yielded an abundance of frogs frantically hopping to escape the blades like porpoises cresting a bow wave. While picking raspberries, a favorite froggy hangout, one fellow landed upon my arm so that I could feel his cool, sticky belly for the moment it took it to realize that I was too warm and hairy for a perch.
The Pacific tree frog has genetic variants in the population that are capable of changing color. Those I see here range from basic green to a pure, bright copper color with variations in between.

A rare few displayed a dark green tint that looked like the result of mixing brown and green. According to a paper by Wente and Phillips published in Animal Behavior (2005), some frogs maintain their color while others change from green to brown according to substrate. Frogs that do not change stick to background colors that match their own, but color-changing frogs do not.
As esoteric a substance as frog manure is, I may be able to collect enough to sell small samples for high prices if I convince fellow gardeners of the value of chitin for plant growth. Regardless, I enjoy the company of the little amphibians even though I’ve got to pay more attention to washing my salad greens.