As we move towards early spring, daytime temperatures rise into the 40’s, increasingly melting what snow there is at the lower elevations. A late-season storm may come through, temporarily reminding us of winter, but the snow will not last long in the valleys. The mountain slopes and peaks may sparkle with a fresh white blanket, but the lowlands are a patchwork of brown, gray, and dark conifer-green. Following the moderating weather and increasing day length north, early migrant birds begin to appear. Some of these species, particularly the American Robin, are actually seen here irregularly through the winter, in small or large flocks. When the flood of migrants begins to appear, though, it’s a sign that spring is on its way.
By late February in most years, American Robins are here in large numbers, calling noisily from the treetops. Black-capped Chickadees and some Dark-eyed Juncos have been here all winter, but now male birds are singing frequently to stake out territory and to advertise to mates. Listen, especially at dawn, for the song of the male Black-capped Chickadees, a sweet whistled “fee-bee.”
The days continue to get longer as we pass the vernal equinox, March 20, that time when the day lasts as long as the night. By now, more migrant birds have shown up or will soon – including Western Bluebirds, Mountain Bluebirds, and Western Meadowlarks – announcing spring to the human residents. As ice melts from low elevation ponds, Columbia Spotted Frogs and Pacific Treefrogs are concentrating at wetlands to breed. The males use advertisement calls to attract other frogs of both sexes, and to communicate with rival males. The Pacific Treefrog’s loud “ribbet” is heard primarily at night, while the Columbia Spotted Frog makes a quiet, low-pitched, rapid clucking sound during the day. After breeding, the Pacific Treefrogs often range up to a quarter mile from their breeding ponds, feeding on small invertebrates; Columbia Spotted Frogs tend to stay close to wetlands.
In the surrounding forest, Varied Thrushes are making their presence known, the males singing a haunting, one-note song which sounds to some like a coach’s whistle. Their songs are conspicuous in the lowlands in early spring. At these lower elevations, the warming weather has probably brought the Striped Skunks out of their winter dens, and you may see one, or the tracks it leaves, as it searches for insects, frogs, and carrion.
As we climb into the mountains, the south and west slopes, oriented to catch the heat of the sun, are losing their snow quickly, while the more shaded north and east slopes will hold onto it longer – well into the summer in high altitude glacial cirque basins. As the melting snow makes the forest floor visible, and the sun warms it, plants begin to swell their buds, or to send up new growth from underground root systems. The earth is becoming bare at higher elevations, particularly on the sunny slopes with southerly and westerly aspects; the streams are running high with frigid snowmelt. It is the breeding season of the threatened Canada Lynx, a long-legged feline with long black ear tufts and a black-tipped tail. These seldom-seen carnivores require forest cover; they feed primarily on Snowshoe Hares, as well as Red Squirrels and other small mammals, birds such as Ruffed Grouse, and carrion. Nine weeks from now, the breeding females will be ready to give birth. They prefer areas of old forest with lots of downed wood for den sites.
By early April, if not before, Tree and Violet-green Swallows have begun to return to the valleys, and you may see a Spotted Towhee, with its striking bold black head and back and reddish flanks, scratching for seeds or insects under dense bushes. The buds of the Western Larch are bright green and swelling at the feet of the mountains, and on dry slopes the Mallow Ninebark, a common shrub with shreddy bark, is starting to leaf out. Turkey Vultures, which are migratory, have returned.
As the season progresses, the songs of Varied Thrushes become unusual in the lowlands; many move up into dense mountain conifer forests to breed. Scouler’s Willows are flowering, and you may hear a male Ruffed Grouse drumming, sounding like an old motor trying to start: “bup bup bup brrrrrrrt!” The relatively common Black Bear and the rarely seen, threatened Grizzly may be starting to come out of their winter dens. Although classified as carnivores, these two species eat mostly vegetable matter. At this time of year, the great majority of their diet is grasses and sedges.
By the middle of April, as the Yellow-rumped Warblers begin to return, you may notice other heralds of spring, such as mosquitoes. Different types of mosquitoes overwinter in various ways: some species have survived the cold as eggs, some as adult females in sheltered places, and a few species as larvae. Ticks are out now, as well, and “questing” for a blood meal, clinging to vegetation and waiting patiently for an animal to brush past. Canada Buffaloberry is showing small, inconspicuous yellow flowers, which come out before its leaves. Look for early-flowering forbs, plants which have overwintered with their energy underground, starting to bloom. On sites that will be quite dry in a few months, you may be surprised by the strikingly beautiful, sky-blue flowers of Long-flowered Bluebells. In many spots, the earth is still moist from the melting snow, and in such places you might find the brilliant blooms of Shooting Star, with their distinctively bent-back pink-purple corollas. Damp woods may show flashes of bright yellow from the low-growing Round-leaved Violet, whose thin leaves may have stayed green under the snow all winter long. Look for the pale, bell-shaped flowers of Utah Honeysuckle, a shrub, hiding under its opposite leaves. In wet, shaded sites, Trillium has poked up from its hidden rhizomes, and now shows a large, 3-petaled, white flower above a whorl of three green blades.
If you hear a bird singing a high-pitched cascade of liquid notes, it’s probably a male Pacific Wren proclaiming his territory. Heart-leaved Arnica has emerged from its underground rhizomes, and Lupine leaves have come up from woody root crowns. Fairybells, leafy plants in the Lily family, are showing nodding, whitish bell-shaped flowers at the tips of their stems.
Native Westslope Cutthroat Trout may be spawning, laying eggs in gravel areas of cold streams. They spawn when water temperatures have warmed to around 50°F. Some have traveled from lakes and large rivers to reproduce, while others live year-round in smaller streams.