The Mountains in Fall
When the chill of night becomes biting and the dependable blue skies of August give way to September’s equivocation of light, rain, and wind, autumn has arrived in the mountains. These days are glorious, the firework finale of summer before the dark of winter. Luminous scarlet leaves of red-osier dogwood reach over the streams, yellow larches light up the forest, and fresh rain sparkles on mushroom caps and blue elderberry.
Animals are visible and busy, gathering food and arranging their winter affairs. Pikas reap their last bunches of hay, spreading them to dry at burrow entrances before hauling them into tunnels for winter. Thrushes prowl the undergrowth, dissecting overgrown porcini to get at the grubs inside. Higher in the meadows at the edge of the tree line, chipmunks climb late-season asters to get at seed clusters, bending the plants to the ground with their weight. Marmots survey their territory from dignified perches atop boulders littering the hillside.
On the slopes of Mount Rainier, autumn ripens like a bruise, blooming in bilberry’s crimson leaves and powdery cobalt fruit, bog gentian’s ultramarine paper lanterns, and the violet swaths of half-withered purple asters. The trickster mountain peeks out of fogbanks, showing a tantalizing glacier above the trees before vanishing in a whirl of mist. Tendrils of fog descend into the forest, turning rows of silver firs into silhouettes. Dimension and scale fall away in the haze, turning the world into a blur of color. As evening falls, that color fades to a gray scale before extinguishing to near-black twilight.
Sitka Mountain Ash | Sorbus sitchensis
White flowering shrubs proliferate along the high hillsides during summer, from buckbrush to saskatoon to elderberry to oceanspray. I have a bad habit of lumping the visual pattern of these shrubs together, letting them fade into the background of my consciousness in favor of showier species.
When autumn comes, however, these plants diverge into a hundred different presentations of leaf and berry and lift the veil from my perception. This is especially the case with Sitka mountain ash, a shrub that paints the landscape with autumnal color.
The symmetrical pinnate leaves of Sitka mountain ash begin to turn a syrupy golden brown in fall, framing tantalizing clusters of warm red berries that will stay stubbornly on the branches well into winter. While unappealingly bitter to humans, mountain ash berries are an important source of nutrition for birds and small mammals during the season when tastier options are rare.
Like many plants when faced with the challenges of altitude, the Sitka mountain ash struts tall through the forests of the mountain foothills, then ducks and hunches down into smaller shrubs higher up, then creeps prostrate across slopes above the tree line. One could easily mistake it for several different plants in a journey upslope.
Blue Knight | Albatrellus flettii
Once summer has departed and taken the worst of the mosquitoes and scorching heat with it, the magnetism of mountain trails is irresistible. The nip of cold winds or an unexpected spatter of raindrops is a small price to pay for the magical sights of autumn. It is a great time to pull double duty as a forager and a hiker, and when I peer beneath bushes in search of fall mushrooms, I often catch sight of an early pioneer of the winter blues.
The blue knight mushroom, also known as the blue polypore, is a fungus with a sky-blue cap (sometimes a mottled pattern of pink and blue with age) and a completely smooth, porcelain-white underside. It looks to me like an especially whimsical fungus straight out of a fairy tale, and even the name of the mushroom is a bit fantastical. The blue knight reflects the powerful moodiness of late autumn, the slippage between planes that feels stronger as seasons change. This mushroom always captures my attention because in a season of warm colors, it is a bold act to be blue—and what artist isn’t drawn to complementary hues?
Black Bear | Ursus americanus
As North American bears go, black bears are the smallest and shyest of the lot. They are also the only species of bear commonly found in Oregon and Washington. Smaller and more mild-mannered than their grizzly cousins, they want little to do with humans and would rather run than engage with you. As long as you pack up your food while camping and respect their personal space if you encounter them, sharing the woods with bears is generally a peaceful experience.
In fall, I am conscientious of intruding on a black bear’s important work in berry patches, where they slurp up pounds of fruit a day with their prehensile lips. A bear takes the job of packing on weight for winter seriously and will feed intensely in the weeks leading up to hibernation, a state also known as hyperphagia. Look for bear signs in fall (tracks, scat, and wide paths of flattened vegetation) and steer clear of wild food pantries that have already been claimed.
Cascade Bilberry | Vaccinium deliciosum
The flavor of Cascade bilberry is so wild and sublime that I get a little superstitious about collecting it. It feels so rooted to place that it seems to me the only correct way to taste it is to bring yourself up the mountain, above the forested foothills and into alpine clearings carpeted with dense, low-growing foliage. There, the leaves of the bilberry bush angle up toward the low-hanging sun, tinted red in a visual echo of the wildfire that helps sustain this rare montane meadow habitat.
For animals who live above the timberline, bilberry is a valuable resource. It prefers the highest and coldest elevations, growing sparsely among the peaks in Oregon and becoming more plentiful toward Mount Rainier and into the North Cascades. Its late fruiting season provides a windfall of food and nutrients, the last great community feast of the mountains before the scarcity of winter. Some species even appear to call a temporary truce of territorial or predatory conflicts to work the bilberry bushes side by side: bear beside chipmunk beside grouse, gobbling as much of the fruit as they can hold.
White-Tailed Ptarmigan | Lagopus leucura
A visitor to the slopes far above the timberline of a Cascade peak is likely to encounter scraping winds, freezing fog, and the unsettling creak of glaciers. Up here the snow never fully retreats, and sparse heather and buckwheat hunch close to the earth and scrabble for crumbs of soil among the rocks. This is the year-round domain of a stout little grouse called the white-tailed ptarmigan. When winter arrives, other animals migrate to warmer southern climes or head back down the mountain to lower elevations where food can be found. Unfazed, the ptarmigan sees them all off and prepares to spend the winter as the only creature on the highest slopes. In making this daunting choice a ptarmigan combines the two very best techniques for avoiding predation: becoming invisible and staying where even the toughest predators won’t go.
A ptarmigan’s winter preparation is conducted mainly through molting as it drops its striped and speckled brown feathers and replaces them with feathers of solid white, like snow building up over rocks. The first flecks of white on a ptarmigan’s shoulders in fall are as incontrovertible a sign of winter on the horizon as the first hints of frost in the air. Once the costume change is complete, a ptarmigan will literally sit out the winter, eating plants like heather, saxifrage, and bilberry and moving very little to conserve energy. Insulated by a thick layer of white down, the ptarmigan is concealed in plain sight except for its dark eyes and beak against the snow.
September Can Sting
Not everyone appreciates the romance of crisp fall mornings. Within the nests of western yellowjackets, autumn is a time of hunger and uncertainty. A healthy colony that has been growing and well fed on protein and nectar all summer becomes a hotbed of dissent when temperatures drop, food runs out, and the queen begins to slip into hibernation and release her chemical reign over her underlings. Disorganized, competing desperately for food, and perhaps even aware of their impending mortality when the hard freezes arrive, ornery yellowjacket workers take to heart the words of Dylan Thomas and do not go gently into that good night.
This is a hard fate for creatures that have dutifully worked on nature’s cleanup crew and pollinator team over the warm months. That knowledge has helped me personally find a bit of understanding and empathy for wasps, and these days I more freely offer wasps scraps of the fruits and fats I’m enjoying in the hope that good karma will get me through the season sting-free. But just in case, I also make sure to pack antihistamines in my trail kit.
Golden-Mantled Ground Squirrel | Callospermophilus spp.
The ground squirrel accompanied me on my ascent to Mount Rainier’s Paradise area, whisking around my ankles and running ahead on the trail before pausing to look back and judge my progress. While it was tempting to ascribe him with benevolent purpose as a guide on the magical slopes, a more pragmatic instinct told me that this bold creature was after food. Sitting upright on the rocks, he assessed me with shrewd black eyes encircled by white fur, wringing his bony little hands and flicking his tail in an impatient gesture. He was so enormously plump from successful autumn foraging (and tourist-schmoozing) that I was shocked at his agility as he scuttled along the rocks. Following my hungry companion up the mountain, I marveled at how everything on Mount Rainier seemed mythically large.
What I didn’t know then is that the Washington Cascades have their own specialized species of ground squirrel. While the golden-mantled ground squirrel (Callospermophilus lateralis) is common in most western mountain habitats, Mount Rainier is home to the
Cascade golden-mantled ground squirrel (Callospermophilus saturatus). This northern species significantly outsizes its counterparts to the south, but you will not typically need to tell the difference between the two because they do not mix ranges—Cascade golden-mantled ground squirrels are contained to a range between the Columbia and Nicola Rivers, and you will not find the more widespread species on those mountains.
It can, however, be handy to know the difference between a chipmunk and a ground squirrel. Chipmunks are noticeably smaller, but the most reliable identification feature to look for is the stripes on their sides that extend all the way up to their eyes, whereas the stripes on ground squirrels stop at their golden shoulders.
Red Crossbill | Loxia curvirostra
It was an autumn evening at the end of another intense wildfire season when the crossbills arrived in our mountain camp. The birds descended in a sudden flurry, and shortly a cloud of dust and a chorus of cheeping began to rise from the firepit that, after several months of fire bans, sat heaped with leftover ashes from the early days of summer. When we came closer for a look, we were greeted by a crowd of crossbills crammed into the metal ring, hopping and scratching and calling to each other. Periodically each one would scoop up a beakful of the ash and chew purposefully, entirely undisturbed by our presence. Pulling our chairs up to the firepit, we watched the smoky golden light of evening illuminate the red feathers of the crossbills like jumping flames. Though our toes remained cold, our hearts were thoroughly warmed.
Watching the birds at work, I racked my brain for an explanation of this behavior and eventually remembered an image of parrots scraping at muddy cliffs to get at mineral deposits. Some follow-up research revealed that crossbills are indeed one of those bird species that maintain the mineral balance in their bodies by consuming ash, rocks, and other seemingly inedible materials. Wood ash in particular is rich in calcium and a valuable supplement to a crossbill’s diet.
The rest of the story of what a crossbill eats can be told by the shape of its beak. At first glance their beaks appear deformed, with the lower mandible curving to the right and the upper one curving to the left (or vice versa—these birds can be right or left “handed”). But this absurd-looking asymmetry is a strategic adaptation to take advantage of physics. Crossbills use these tweaked beaks to open the tough scales of tree cones, inserting the crossed tips under the scale of a cone and then using an open-and-twist motion to lever the scale and snatch the seed tucked underneath. This is a useful tool for the stubborn and fire-adapted cones of the mountains.
Larch | Larix spp.
The larch pushes the boundaries of what it means to be a conifer. It’s fun to imagine prickly traditional evergreens looking on with disapproval as the larch turns its soft needles a gaudy, glowing gold before dropping them entirely to stand scandalously naked until spring.
The yellow is due to some interesting color science: Pigments in the foliage, called carotenoids, give larch needles (and all leaves that turn yellow) their hue. This is present in foliage at all times, but is covered by chlorophyll’s green during the growing season. In other types of trees, pigments called anthocyanins produce a red color when exposed to cold and sunlight. More simply put, a tree that turns red has added something chemically, while a tree that turns yellow has had chlorophyll subtracted; it becomes the true color it always was underneath.
Subalpine larches live at exceptionally high and hard to reach elevations. If you’d rather skip the strenuous hike up alpine trails, consider seeking out the alpine larch’s cousin, the western larch. Western larches are just as yellow and easy to spot on a scenic drive or casual walk through mixed ponderosa forests east of the Cascades. This species requires dryness more than elevation; they scale the northeast side of Mount Hood almost up to the timberline but barely make an appearance on the foggy slopes of Mount Rainier.
Fall Raptor Counting
Most of the Pacific Northwest falls under the Pacific Flyway, a band of airspace stretching from Alaska to Patagonia that forms the route many bird species take in their annual migrations. The dynamic topography of the mountains creates updrafts and thermals that birds like to ride, so a long chain of mountains like the Cascades is a convenient wind tunnel to a migrating hawk.
Just as whale watchers gather on the coast to observe gray whales on their migration route, birders flock to certain prairies, lakes, and mountains to see the seasonal flow of birds. For many, it’s a chance to see species that are only in the region briefly.
One such site is the Bonney Butte HawkWatch, a raptor research site located on the southeastern shoulder of Mount Hood. The site is busy from late August to late October with HawkWatch International staff and volunteers counting and banding raptors to monitor the population health of migratory species like the golden eagle, sharp-shinned hawk, and turkey vulture. Bonney Butte is open to the public, and any curious birder is welcome to visit and watch the count.
Even if you aren’t within range of a research station, the project of monitoring migratory species is something that we all can participate in through the magic of citizen science in the digital era. Convenient tools like iNaturalist and eBird allow anyone with a smartphone to log information about bird sightings, which can then be verified by scientists who collect and refine data that will eventually be used to help make decisions about land management and species conservation.
Excerpted from CASCADE OF LIFE by Emily Poole (September 2026). Published by Skipstone Books. All rights reserved. Used with permission from the publisher.
About Cascade of Life:
Cascade of Life invites readers to step beyond the typical field guide and into a deeper dialogue with the natural world. Artist and naturalist Emily Poole explores the wondrous variety of the Pacific Northwest – from rocky shorelines to alpine slopes to arid steppes – through the rhythms of the four seasons, spotlighting species that are especially active at different times of year. Original illustrations and essays feature popular species like gray whales and Anna’s hummingbirds, as well as overlooked or misunderstood plants and animals, such as pickleweed and coyotes.
Blending stunningly vivid paintings with personal anecdotes and field-based insights, each chapter encourages the reader’s curiosity and offers accessible, hands-on activities to deepen their connection with nature. Part field guide, part journal, Cascade of Life is a welcoming, inspiring exploration of Cascadia’s landscapes and the species that define them.
About Emily Poole:
Acclaimed artist EMILY POOLE has been exploring the wild spaces of the western United States since childhood. Her work has been used by organizationssuch as Creature Conserve, HawkWatch International, and the National Museum of Wildlife Art and has appeared regularly in High Country News. Her illustrations have been featured in six natural history books, including BirdNote, Northwest Know-How: Trees, and A Little Book of Hummingbirds. She lives in Eugene, Oregon. Find her online at epooleart.com.
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