Scrub-Forest

The Vital Predator

The merciless law of predation might at first thought seem cruel; but the predator plays a vital part in maintaining the balance of the biotic community. Without the controlling factor of predation, prey species quickly enlarge their populations. If plant eaters are not checked, the resulting excess population exceeds the carrying capacity of the range. Food supply rapidly diminishes. In a damaged range, competition and stress result, usually culminating in a massive die-off through starvation and disease.

Ironically, predators thus provide a service to their prey. First to fall to the predator are the old, the diseased, the unwary, and the young. By removing many young and old deer from a typical herd, cougars lessen competition among the deer for choice range, thus tending to keep herbivore numbers at parity with the land’s carrying capacity. Only the strongest and wariest deer survive, ensuring that the fittest will continue the species. When man upsets this delicate balance—destroying predators in the hope of increasing numbers of game animals—the result is ecological disaster. In the 1930s, in a misguided attempt to “preserve” the whitetail deer herds of the park’s North Fork area, many coyotes and cougars were exterminated. In 1935 alone, 50 cougars were killed. Relieved of the pressure of predation, the deer flourished. In a few years, however, the normally adequate range was severely overbrowsed. Suffering also from this imbalance were wapiti (“elk”) and moose, ungulates that share the winter range with deer.

Some predators are more specialized than others. The Canada lynx, for example, has oversize feet, an adaptation that helps it move across deep snow without breaking the surface. As a result, it is an efficient predator of the snowshoe hare, another large-footed animal. Relying on this adaptation, the lynx feeds almost exclusively on snowshoe hares. Consequently, its numbers inevitably fluctuate with the 10-year “boom and bust” cycle of the snowshoe.

The coyote, on the other hand, is a generalized predator, exploiting whatever prey is currently abundant. Should mice or ground squirrels be in short supply, it will subsist on anything from grasshoppers to berries until favored prey again becomes available. (Animals that normally eat both plant and animal food are referred to as omnivores.) Generalized predators are thus better equipped to survive temporary ecological imbalances, maintaining their numbers at relatively consistent levels from year to year.

Carnivores all, the animals on these pages illustrate various adaptations for capturing prey.

The population of the Canada lynx, which is widely distributed in Glacier’s coniferous forests, fluctuates in cycles. The lynx is abundant or scarce depending on the population condition of its chief prey, the equally cyclic snowshoe hare.

The cougar, which feeds primarily on deer, requires a large territory. Because of its strength, stealth, and speed, American folklore has given this wary cat a false reputation as a man-stalker.

The red fox depends largely on a well-developed sense of smell to locate its prey; it also relies on its keen eyesight, speed, and agility to capture mice, hares, birds, and whatever else it can run down or surprise.

To feed its demanding young, the Swainson’s thrush hunts for insects along the forest floor and in the dense underbrush. This thrush relies on its secretive behavior to protect its nest near the ground from detection by other predators.

Armed with enlarged forelegs, the crab spider waits on or near flowers to ambush visiting bees, flies, or other insects. Its venom produces a quick kill, allowing it to attack insects many times its own size.

The spotted frog is a large-mouthed predator that not only eats water striders and other insects but also gulps down smaller frogs and small fish.

Protective Coloration

To escape extermination, each species must in some manner foil its enemies. Protective coloration is one of the more common adaptations helping to do this. Most animals resemble their environment to some extent. The conspicuous markings of some, like the bitter-tasting monarch butterfly or the striped skunk, seem to function as a warning to prospective predators that it is in their best interest to look elsewhere for a meal.

Some animals, such as the white-tailed ptarmigan and the snowshoe hare, have seasonal changes in plumage or pelage, wearing white in winter and brown in summer. Even predators, such as longtail and shorttail weasels, benefit from seasonal camouflage. Protective coloration makes them less noticeable to prey species and to larger predators.

Many insects, too, change coloration with the season. Bright green grasshoppers of early summer become more brown with each molt, matching the changes in the surrounding vegetation.

Obliterative shadingis especially important to animals that frequent more than one habitat. Seen from above, turtles match their dark background; from below, because of their lighter underbody shading they blend into the bright skylight.

Disruptive colorationaids in breaking up an animal’s outline. Butterflies and moths commonly have disruptive wing markings. The distinctive shapes of eyes can be concealed. Eye coloration may mimic body color—as in the green katydid—or the eye may continue disruptive body markings.

Ground-nesting birds are especially vulnerable to attack. Their eggs tend to be heavily blotched with earthy colors, making them less conspicuous. Chicks also carry these disruptive colorations on natal down.

Most mammals, with coats of brown or gray, are inconspicuous when motionless. Deer fawns are endowed with speckled coats, mimicking the sun-flecked forest floor; this disruptive coloration, coupled with absence of scent and their instinctive “freezing” behavior, makes it difficult for predators to detect them.

The whitetail deer not only uses its white “flag” to warn others in the herd of danger; it also allows a pursuing predator to use it as a target. When the tail is suddenly dropped—abruptly obliterating the bright white patch—the deer seems to disappear into its dim surroundings.

Since overly conspicuous animals are prone to predation, natural selection favors development of appropriate camouflage.

For such ground-dwelling birds as the white-tailed ptarmigan, camouflage is an important survival adaptation. The ptarmigan changes its plumage to match its surroundings: it is white in winter, speckled in summer. Moving slowly and refraining from flight, it is less likely than more-active birds to be detected by sharp-eyed, motion-conscious predators.

Birds that when hatched are covered with down and are able to move about freely are calledprecocial. They are less dependent upon their parents than arealtricialyoung, which are naked and helpless when they hatch; but they must rely heavily on a resemblance to their surroundings for survival during their first flightless weeks. This spruce grouse chick, which blends into its sunflecked forest-floor habitat, is an example of a precocial bird.

The bold disruptive pattern of the killdeer chick’s plumage helps this precocial bird avoid detection in its open-prairie environment. This adaptation, coupled with the chick’s instinct to freeze at the approach of danger, ensures that enough young will survive to perpetuate the species.

Ursus arctos horribilus: The Vulnerable King

At the apex of the food pyramid, this great beast is unquestionably the king of Glacier’s biotic community. Yet the long-range future of the grizzly bear is uncertain. With the grizzly exterminated from most of its former range—which once extended into the midcontinent and south into Mexico—its numbers have dwindled in proportion to its diminished range. Present concentrations in the contiguous United States remain in and around Yellowstone and Glacier National Parks. Probably fewer than 200 of these magnificent creatures live in Glacier National Park.

Grizzlies are easily distinguished from the more common black bear. In addition to larger size and heavier build, grizzlies have a characteristic shoulder hump; long, conspicuous claws; and a broad, concave face that gives them a “dished-in” appearance. Fur is usually brown; like the fur of the black bear, however, color may range from black to yellowish. Light tipped hairs make the fur appear frosted, giving rise to the nickname, “silvertip.”

Grizzlies, popularly considered arch predators, are more accurately described as omnivores. Carrion, grasses, cow parsnip, and several species of berries, bulbs, and tubers make up a grizzly’s diet, along with insects, small mammals, and an occasional ungulate that it can catch. As a result, grizzlies play several roles in the biotic community, functioning as herbivore, scavenger, and predator.

Ranging widely in all life zones, grizzlies follow the spring snowmelt up to the alpine meadows, returning to lower elevations to hibernate from November until April. One to three cubs are born in midwinter during hibernation. Since the maternal bond lasts two years, a sow will accept a mate only every other year. Mortality of subadults is high, resulting principally from competition among the bears themselves. As with most animals, range—habitat—appears to be the limiting factor of grizzly populations.

The grizzly is normally shy and fearful of man—but highly unpredictable. Wounded or sick bears, sows defending cubs, young adults, and bears that have become conditioned to human scent are the most dangerous. As humans continue to encroach on grizzly territory, odds of confrontation also increase. Recent fatalities and personal injuries inflicted by grizzlies pose a vexing problem to the National Park Service, which is charged with visitor safety on the one hand and protection of the park’s remaining grizzly population on the other. Continuing study of grizzly ecology and increasingly enlightened bear management programs will, it is hoped, allow man and bear to co-exist in a wilderness both require.

Grizzlies are fond of succulent spring grasses.

Traversing all life zones in the park, the grizzly is a true opportunist, eating anything from ants and berries to wapiti.

Seldom will a grizzly exceed 225 kilograms in Glacier. This is a young adult.

Bald Eagles and Kokanee Salmon: A Recent Gathering

In 1916 the kokanee salmon, a small, land-locked form of the Pacific coast species, was planted in the Flathead drainage. With the first planting augmented by additional stockings, the fish thrived in cold, deep Flathead Lake, and, to a lesser extent, in Lake McDonald. The salmon fed almost exclusively on zooplankton.

By the mid-1930s, salmon runs were becoming established. The outlet of Lake McDonald provides an ideal spawning site for the salmon. The fast-flowing water is clear, cold, and shallow, and the creek bed is gravelly.

Averaging 0.3 meters in length and weighing less than a half-kilo, the 4-year-old adult salmon cease feeding and begin to migrate. Many thousands swim the 100 kilometers from Flathead Lake to McDonald Creek. Males appear in the creek first, arriving in late September, and are soon followed by the females.

Using her tail to dig a redd (a shallow nest depression), the female deposits about 650 eggs. After fertilization by the male, the eggs are covered over. The adults die within three weeks after spawning, their bodies exhausted from the rigorous migration journey and the weeks-long lack of sustenance.

Egg fatalities are high, due to stream erosion and disturbance by other spawning salmon. Hatching in late March, the fry work their way out of the gravel and migrate downstream.

Attracted to the 75,000-150,000 salmon concentrated in a 3-kilometer stretch of shallow water, bald eagles begin gathering at McDonald Creek in October. It is not known where the eagles come from or where they go after the spawning run. Glacier has fewer than 20 summer-resident bald eagles, and these are distributed among the remote lakes of the North Fork area.

In 1939, 37 bald eagles were counted along the creek. By 1969, 373 were reported, representing approximately 10 percent of that year’s estimated winter population for the contiguous United States. Since 1960, the count has averaged 240 birds. (In 1977 there were 444.)

Eagles feed by swooping down to pluck salmon from the water or by wading out to grab a fish stranded on a shallow riffle. An eagle may consume as many as six fish a day. Immature birds are not as adept at catching fish and may harry adults or other immatures into releasing their catch.

From its vantage point, this mature bald eagle examines the waters of McDonald Creek. Average weight is 5.7 kilograms; average wingspan is 2.2 meters. Females are slightly larger than males.

This immature bald eagle lacks the familiar white head and tail of the adult birds. It will not acquire those markings until it is several years old.

Breeding male and female kokanee salmon are easily distinguishable; as spawning time approaches, they change appearance. The dark gray backs turn red; heads become green, and the males develop humped backs and hooked jaws.

Swooping upward with a fish, a mature eagle heads for a convenient perch to consume its catch. A strategically located tree may contain 30 birds.

A Triumph of Many Colors

Grassland, meadow, tundra, or any other area in Glacier suitable for plant growth and supplied with abundant sunlight produces an extravagance of wildflowers. This display of various shapes and colors is neither an accident nor a mere decoration of nature. Nor would Earth’s recent explosion of mammal and bird species have been possible without the evolution of flowering plants.

Two hundred million years ago, early in the Age of Reptiles, angiosperms (flowering plants) had not yet evolved. Plant reproduction still relied on spores and cones. Then, during the Cretaceous Period, the last sediments were being laid down in the inland sea that covered most of Montana. (It was these sediments that the ancient Precambrian rocks of Glacier’s mountains later overrode, forming the Lewis Overthrust.) During this period the evolutionary miracle occurred: flowering plants—grasses, vines, shrubs, broadleaf trees, wildflowers—inherited the Earth.

The timing was important. As Earth’s tropical climate gradually changed to temperate extremes during this period, the domination of cold-blooded dinosaurs ended and the moisture-demanding coniferous forests that had covered the earth in green monotony began to shrink. Angiosperms provided a solution to the ecological void: grasses and forbs grew where trees no longer could. Most important, relationships evolved between this new class of plants and the relatively few species of insects then existing.

Insects began to use the pollen of flowering plants; the angiosperms, in turn, evolved bright petals and nectar that exploited visiting insects for the plants’ own reproductive purposes. This partnership allowed insects to diversify rapidly, evolving new, specialized forms such as bees, moths, and butterflies. As a result, predatory forms of insects and arachnids also rapidly diversified.

The most dramatic change, however, involved warm-blooded birds and mammals, whose high rates of metabolism required high-energy fuels. Unlike gymnosperm seeds, which contain no protective covering, angiosperm seeds are surrounded by a fruit. The development of these highly nutritious seeds, and the attendant explosion of insect species, ensured survival of the newly evolved birds.

As birds diversified into seed-eaters, insectivores, and carnivores, mammals, then uncertain little ratlike creatures darting among the feet of dinosaurs, began a rapid rise to dominance; grasslands promoted an explosion of herbivorous and carnivorous species.

The evolution of angiosperms, and the animal revolution it made possible, came with amazing speed. Most significant, it was a vital first step upon which the meteoric rise of man depended.

Indian paintbrush is common at all elevations below tundra. It may be white, yellow, orange, pink or red. The actual flowers, inconspicuous and green, are surrounded by brilliantly colored bracts. Semi-parasitic on other plants, paintbrush is normally found growing in conjunction with other wildflowers; its roots steal sustenance from neighboring plants.

Yellow stonecrop, widely distributed in forest and scrub-forest zones, is one of the park’s few plants having succulent leaves, an adaptation that helps it survive in such situations as dry, rocky outcrops.

The Calypso orchid grows in the cool, shadowed forest where light is dim. It lives in partnership with certain fungi that exist about the orchid’s roots and seem to help nourish it.

Silky lupine, a legume, has nitrogen-fixing nodules on its roots, thus allowing it to grow in nitrogen-poor soil. It is widely distributed in grassland and forest communities.

Fire Succession: Key to Continuity

Most of Glacier’s fires are lightning-caused. Strikes may flare up immediately; or fires may smolder in the forest duff for days until fanned into flame by wind.Ground firesmay race through the forest understory, causing minor damage; or they may bridge the understory and reach the canopy, thus becoming rapidly spreadingcrown fires. Under certain conditions, uncontrollable infernos may develop, generating terrific winds and heat. These rare conflagrations are calledfire storms.

Every type of forest habitat hasclimax vegetation—trees and shrubs that are best suited to the site and thus maintain themselves indefinitely if not disrupted.

After a major fire, habitat conditions are usually so altered that the site must pass through severalseral stagesbefore conditions are such that climax vegetation can return. Asereis a series of plant communities that follow one another in orderly fashion until climax conditions are again reached.

Lightning fires occur most often during the hot, dry weeks of late summer.

When the forest is dry, lightning often causes quick flare-ups.

The forest may continue to burn for days after the main conflagration has passed.

After a major fire, sun-loving grasses, shrubs, and wildflowers quickly invade the former forest. Deer and wapiti benefit from these new food sources.

Lodgepole pine, a pioneer species quick to take over burned areas at lower elevations, grows rapidly. These trees are five years old.

This is a Glacier National Park forest 80 years after a major fire.

Sudden hammering made me jump. Above the forest darkness, a pileated woodpecker leaned out from a high larch snag, braced against the trunk by its specialized, stiff tail feathers. This was the first time I had seen this big white-and-black bird, the “cock-of-the-woods.” There was ample evidence of his work: the deep, oblong excavations in the trunk and the pile of large wood chips at its base, both characteristic of this species. Again he hammered, and I could see the chips falling. After a little edge-work around the hole, he extracted a grub and flew off, yammering against the advancing dark.

Near a stream I stopped to sit down, to listen to the water and maybe catch sight of some small animal. Across the narrow defile, from a slope dense with young hemlock, came the buzzing note of a varied thrush. Several notes followed, all on a different pitch, all drawn out, level and clear; the quality was pure but songless, disjointed, deliberate, like someone testing the reed of a strange woodwind. There seemed no gladness in the heart of this thrush. The song was dark, haunting, lonely.

On the trail ahead I could make out a bird hopping rapidly along. After passing the spot I could hear its song. There couldn’t be a hundred meters between us, yet it seemed to be coming from a great distance. I listened for as long as it would sing. I tried to hear it for what it was, a male Swainson’s thrush proclaiming its territory. But the ethereal, flute-like phrases seemed an evensong made not for man’s ears but only for the forest itself.

I hurried on after the bird had ceased. It was getting dark beneath the trees, but I was beginning to be aware of creatures underfoot, the mad dartings of shrew and vole, more imagined than seen. When a deer mouse jumped away I got out my flashlight. Soon the beam caught a woodrat sitting atop a fallen log. The light didn’t bother him in the least; as I approached, he picked up his bushy tail in his forepaws. Whiskers twitching, he looked more caricature than real. Then he bounded off the log with graceful, arching hops, and disappeared into the night.

Against a patch of sky that appeared in a clearing, I could make out bats, circling and dipping like swallows. Locating a hovering moth, I kept the light beam on it until it vanished into a furry streak of silence. It was time to head back.

By now it had become utterly dark within the trees, a moonless, sightless, alienworld, given over to the marble-black eyes of the small night mammals and the creatures that hunt them. I thought of the strange, unseen societies of the flying squirrels, the nocturnal counterparts of red squirrels; of the great-horned owls, inspecting the same ground the goshawks scanned during the day. Perhaps a foraging red fox moved through the darkness nearby, or a coyote on night patrol.

The flashlight beam probed ahead along the trail. The exposed roots were given unnatural shading and they seemed to thicken and squirm as I approached. On either side the tree trunks appeared to step backward from the dim glow of the light. I felt lost in this night, thinking of the great darkness in all the timbered ridges that ran westward from the Divide. In this vast cathedral of crowded tree and peak, night was stood on end, the stars shrunken to a circle overhead, as if seen from the bottom of a well. Mouselike, shivering, insignificant in this wilderness, I scurried back to find a fire and fill my empty senses with its heat and snap and light, holding off the fright of night and thinking of tomorrow’s sun.

The crowning beauty of Glacier—the high, cirqueheld meadows that scent the wind with wildflower and waterfall—belongs to the zone of scrub-forest.

At Logan Pass you are introduced to the highlands. Here an exquisite upland basin holds the Hanging Gardens, a wildflower-clothed gradient laced with stair-step bogs and lines of wind-bent subalpine fir. In the dawn sun, before the first engine noise, it shines unbroken, dewbright and sagging like a spider web secured to the circle of surrounding peaks.

This is the region the hiker remembers best. The tall mountains wear this zone close to the cliffs, and the trails encounter it near the passes or follow it for long, level stretches, as along the Garden Wall. I remember Preston Park and Fifty Mountain, the fire-touched bench of Granite Park and the first sight of Sperry chalet, built on a brow of rock at the upper reach of trees. But most of all I remember the terrible waterfall that becomes Bowman Creek, the plunge of nearly a kilometer that drains the magnificent upland bench called Hole-in-the-Wall.

September. The season is growing late, the meadow-rue dying and the leaves of the wild strawberry failing at last. Everywhere the red contagion of autumn surrounds thevital green. The lower valleys have lost the whistle of ground squirrels. They sun themselves no longer these late, mild days. Ripe, sluggish, and hawk-vulnerable, they sensed the need of hibernation.

It has been eight years since I last visited Hole-in-the-Wall, but I retain its dimensions and hear its dozen waterfalls at will. Once you have seen this basin you have a measure by which to judge the high country and a thirst for the meadows at tree-line.

In Glacier, treelimit ranges between 1,850 and 2,300 meters, depending on local conditions. The upper limit of tree growth—rarely an even, horizontal line—is generally an indistinct band running erratically across a mountain’s face: a tension zone reflecting variations in wind and sun exposure, degree of slope, snowpack accumulations, and the presence of adequate soil and water.

Subalpine fir, whitebark pine, and Engelmann spruce do not relinquish easily their upward climb; where conditions become severe, their growth is retarded and their stature dwarfed. Deformed and pruned by wind, their leaders winter-killed when they outreach the protection of the winter snowpack, trees become shrubs, forced to hug the ground. Size belies age in these elfin forests, or krummholz, where the growing season is painfully brief and progress is always uncertain. A twisted, gnarled little bush, more snag than live branch, bearing a single cone or two, may be senior by a century to the giants of its race in the valley below, which yearly shower the ground with an abundant crop of cones.

This time I will come from Goathaunt, passing Lakes Janet and Francis, reaching Brown Pass from the east, and camp in the spectacular garden between Brown and Boulder Passes.

Meadows and rock slides break the forest as the trail gains elevation and distance through the valley. The spruce and fir thin out rapidly at the valley head, the trail climbing the grassy slope to low, broad Brown Pass. Below the pass is Thunderbird Pond, which receives the meltwater from a glacier high on a shelf of Thunderbird Mountain and is bordered by a low jungle of willow. In the water stands a bull moose, its heavy, fully formed antlers ready for the season’s impending business.

I was hoping again to see Cassin’s finches and Audubon’s warblers on the pass; but the fir grove is quiet. Sitting down to rest and listen, I become aware of a strange silence. No birds sing or flit among the trees, no alarms pass back and forth among alert ground squirrels. There is no wind—an odd condition for the Continental Divide. This place seems to be holding its breath. High overhead, a veil of cirrus cloud arranges long spears across the sky.

Moving off the pass, along the dome of Mt. Chapman, I experience anew the old excitement of this high country. Abruptly the gorge of Bowman valley opens up, revealingthe twisting blue snake of Bowman Lake far down the narrow, cliff-imprisoned valley. Here again are the northern titans—Numa, Peabody, Boulder, Thunderbird, and Rainbow; and Carter, with its high glacier baring blue ice teeth to the sun.

It is not the climb that makes your heart pound now; the trail is suddenly narrow and cliff-defiant, cut by the plunging waters of snowbanks far above. These are splendid peaks, unmatched in a land of muscled, brutal earth. Even the air seems to retain the scent of glacier work.

At last the view of Hole-in-the-Wall, a staircase cirque excavated between the gigantic spread ribs of Mt. Custer. The slopes of beargrass are seed-spotted and gaunt now, the white fullness gone. Western pasqueflowers have accomplished their magic transformation; known in this season as old man’s beard, they nod their tufts of grizzled seedhead silk in the wind. Red and yellow monkeyflowers bloom yet, crowding along the many stream courses, and waterloving sedges and mosses surround pools of collected water on the broad horseshoe tiers.

A spur trail drops down into the campground on the last ledge. Through a cleft in its lip plummets the gathered water of the basin. From the valley below, the waterfall appears to be springing from a hole in the headwall, giving this basin its name. Down, down, down, roars the water where once a mighty glacier ground its teeth.

I leave until later the making of camp; by now the sharp shadows of Boulder Peak stab the valley forest and are beginning the upward assault of Thunderbird.

Around the basin headwalls, last winter’s snowbanks remain formidable. Snow caves send out meltwater torrents. Glacier lilies and patches of spring beauty line their fringes. Pasqueflowers bloom in pockets. Here, among the asters of August, bloom also the first flowers of spring, shooting up as the snowbanks shrink, making these spots of snow-free ground a patchwork of May and July, August and June. The shrubs that line the furious water are willows, still bud-swollen this tenth day of September. The coming days will bring a sharp surprise.

Winter will soon stop the melting of this snow. Could it be that I am seeing the first year of a reawakening ice age? If so, each year the snowfields would grow thicker and broader, connecting the shelves into one ice mass again, lilies and willows entombed, the summer heat failing to rescue them, until the ice at last began to slide, stripping the soil and once more plucking at living rock.

Then these dwarfed fir, which cling precariously to the cliffs and hide behind the backs of boulders, would be in more danger than they were from their recent antagonists. Engulfed by ice, they would know the shearing wind no more. Their skeletons would rain down into the valley below, signalling another long forest retreat. But they have waited out the mountain ice before and would send their seeds again to this valley,changed however it might be, as they have always done.

Evening brings out two sleek mule deer does. As they graze, their large ears stand erect, sorting out the lesser sounds from the ceaseless roar of water. Both raise their heads and point their ears, statue straight, at the scuttle of a porcupine. A noise among the rocks draws a backward glance and focus of those ears. I would like the sensitivity of such fine equipment, to hear what deer have always heard.

Setting about the business of camp, I wonder about those animals that watched me for a while, then moved off, having seen a tent go up before. With the appearance of the moon the wind increases and they test the air more often now. Do they have visions of cougar or grizzly with every snap the wind delivers?

In summer these high meadows see a surprising variety of animal life. Briefly out of hibernation are marmots and the handsome golden-mantled ground squirrels. Mice, voles, shrews, and woodrats run among the shadows, feeding on the season’s feast of seeds and insects. A nightmare for these are the fierce little weasels that haunt the rocks.

Tracks of cougar and wolverine are sometimes seen, often teasingly fresh; to glimpse either of these elusive predators is to taste the finest wine of wilderness.

Before the berry season, grizzlies grub the meadows for the tasty bulbs of glacier lilies and the tubers of spring beauty; often distracted by the scent of a ground squirrel in its burrow, they sometimes make a huge excavation for a small reward.

White-crowned sparrows sing in July from the low tops of the battered trees, though their nests are on the ground below. Grey-crowned rosy finches patrol the drier ground for seeds while water pipits hunt insects in the wet areas. High above, a golden eagle scans the basin again, circling slowly before following a ridge south to sight another likely slope in its 10,000-hectare territory.

The moon shines through the tent top. The wind, blowing more violently now, shivers the nylon and interrupts the voice of the waterfall. I have followed the pasqueflower run from the April prairies here to its highest bloom near treeline. I think about the triangular seed pods of the glacier lilies, colonies of steep-throated blue gentians, and the season’s last glory of goldenrod. Indian paintbrush, from white to fire red, blazes the slopes that light the fringes of sleep.

I awake to a determined rain, the moon gone and the tent shuddering with wind-blast. I try not to think of the steel-cold air, and slip into a fitful sleep that seems an endless treadmill of rocky trail.

Stiff and unrefreshed, I look out into the dawnless morning. The tip of Thunderbird is detached from its base by grey clouds swirling at its throat. A wave of sleet slants down, dancing on the rocks, chanting triumphover the buried, bent, and broken flowers of yesterday.

So I must make my escape, short of Boulder Pass. Unattainable now, invisible above the cirque, that high pass grows in my memory. This testament to what a glacier can do, to the struggle of trees and the life-pioneers that invade such harsh places, is at my feet but shrouded with snow. My hands grow stiff and numb in the blunt work of packing up.

I had wished to see Kinnerly Peak again, rising from the western Kintla valley, and walk along black ledges of the lava that floors the pass. Beyond it grows a grove of subalpine larch, stately, seldom encountered, the least common tree species in Glacier. Confined to this narrow zone between forest and alpine, it reaches up tall and proud, impervious to the gruelling climate that makes cowering shrubs of other trees.

But all must wait another year, for this season comes down hard. And the will of winter is to erase whatever summer had devised.

Porcelain-cold, the November sun dawns in the southeast sky. The ledges, ice-encrusted, layered with sleet from a recent squall, whistle the cold morning wind aside. Rattling down, a slide of rock plunges off the final ledge, seconds passing before the hollow sounds of impact clatter back. Like an apparition of winter itself, white beard bent sideways by the wind, a mountain goat steps to the precipice edge. Looking out across the vast white void, its long belly hair and pantaloons streaming with the ceaseless wind, this strange animal, product of some unfathomable ingenuity, hesitates but a moment; dropping down from step to invisible step along the sheer rock face, fracturing the ice glaze as it goes, it turns a wall and disappears. A nimble, eight-months-old kid follows.

Blinking and twisting in the dull light, the shower of shattered ice clinks softly downward against rock, fading away like the short summers of this place.

But while the wind chants winter, life has made a passage here, and also waits, hidden in seed and root and den.

■The nanny and her kid have bedded down now, looking across the deep, snowy basin below. Their ledge shines with the first spear of sunlight.

Far below the pass that connects MountSiyeh to the snow-giants Matahpi and Going-to-the-sun, three male white-tailed ptarmigan emerge from their night’s huddle within a snowbank and step out to peck at an exposed mat of willow. Ptarmigan, the only birds on the winter tundra, wear white plumage in this season, helping to camouflage them in the snow, just as their mottled brown summer plumage makes them difficult to detect among bare rocks. There are few predators here to hunt them now, but they move with habitual slowness; quick movement can be fatal when summer brings numerous eyes to scan the slopes. With legs and feet heavily feathered and sharp claws to scratch for food beneath the snow, the ptarmigan live at truce with winter. When blizzards rage between the peaks, they nestle together in snow dens, beyond the reach of the winds. Ptarmigan hens winter lower in taller willow thickets, but the males prefer to take their winter as high as possible.

Now they crouch behind the wind-deflecting rocks, dozing in the meager warmth of the morning sun.

Near the snowless summit crags, a flash of brown fur zigzags among the rocks. That would be a pika. Only for a moment does it show itself, so quickly does it move.

Also called the rock rabbit, the diminutive pika belongs to the order of hares and rabbits. Resembling a small guinea pig, this sturdy creature spurns hibernation as a way to beat the challenge of winter. Instead, it spends the summer laying in a store of hay for the lean season, spreading cut grass to cure upon the rocks and tending its “haystacks,” on which its survival hangs.

Winter is a great peril to small mammals. Their small bodies, because of a large surface area in relation to volume, retain heat poorly, and their high metabolic fires consume calories quickly. Great amounts of energy are required to sustain an active animal in rough terrain, placing further demands on the animal’s capacity to survive the cold. The pika may need to stack as much as 25 kilos of hay; to keep its furnace burning during winter it will have to fuel its stomach almost hourly.

Small animals of cold climates often show distinctive body adaptations. On the pika the small, rounded ears lie flat along the head, the tail is inconspicuous, the legs are short; heat loss from exposed surfaces is thus reduced. Fur insulates the soles of the pika’s feet while at the same time providing good traction on steep rock faces.

Hidden below these rocks are the hibernating marmots and the sleeping ground squirrels. Beneath the snow the mice, shrews, and pocket gophers struggle on with their lives. But above ground, directly confronting this arctic climate, are the pika, the ptarmigan, and the mountain goat.

A triumph of adaptation, the mountain goat faces the winter day without benefit of either the pika’s den or the ptarmigan’s snow roost.

The nanny and kid descend from theirledge to search out browse at treeline with other members of a loose band—yearlings, young males, other nannies with kids. At the fringes of the band a solitary adult billy only grudgingly associates with other members of his kind; for this is the season of rut.

Not really goats at all, these relatives of the European mountaineering chamois are insulated from the wind by coats of long, hollow-haired fur overlying woolly underfur. They are stocky, stiff-legged, and deliberate, able to negotiate the walls and pinnacles with their superbly adapted hoofs. The unique design of these hoofs gives the animal great traction and stability on precarious crags. Opening towards the front, the cleft between the two hoofs spreads each outward as the animal descends a slope, helping to grip the rocky surface. In addition, the large, rough, and pliant sole of each foot conforms to the bare rock, increasing traction.

There is little need for the goat to leave its steep sanctuaries; it can subsist on lichens and mosses if browse is not available. It depends on the inaccessibility of the cliffs for its security. Accidents, avalanches, and rockfall are greater enemies than predators. Golden eagles sometimes attempt to knock newborn kids from ledges and a young goat quickly retreats under its nanny when an eagle soars by. With the protection of sharp spike horns and a terrifying terrain, adult goats seldom fall victim to cougar or grizzly.

It will be a long time before the snow releases this land and wapiti, bighorn, grizzly, and cougar wander back into these high basins. In this winter minimum of life, the spring songs of rosy finches, water pipits and white-crowned sparrows seem an impossible extravagance.

■I am drawn to the spring tundra—to the vigor and tenacity of its sparse life—where survival itself seems ceremony enough. But it is a strange world, where a man is out of perspective. Here the plant cover is carpet-high, and distance, for the lack of trees, tricks the eye. Here the wind, snow, and sun quickly burn skin, and the intense light, reflected from snowbanks, stabs at the eyes. Almost instantly, a sandwich is sucked dry of its moisture. The desiccating wind probes the ears until it seems at last to pierce your brain. Except for fearful mountain walls the only shadow is your own. Animals seem somehow remote and unknowable, as if seen through glass. A day on the tundra and you feel the want of a company of trees.

Yet once exposed, you acquire a craving for the look of tundra. Nowhere else is there such an impatience for spring—the flowers rush into bloom; the male water pipit soars, its skylark song crystal sharp in the thin air. The nesting birds are restless, for sun-days and warm days are few, precious, and quickly spent. Insects and spiders abound—flying about the peaks or crawlingamong the rocks.

Summer brings bands of bighorn rams up from the valley to explore the highest meadows. Though not so sure-footed as the goats, they too have hoofs adapted to climbing steep faces, and they walk the slopes not far below the goats.

Marmots, which whistle sharply when threatened, spend their days sunbathing and grazing; they must fill out their now loose-hanging fur coats with life-sustaining fat for the coming winter.

Alpine animals are blessed with mobility and can choose their weathers, retreating to burrow, den, or rock-harbor to escape the worst fury of storms. But what about the plants, rooted forever in one spot, assaulted by an untempered sun and a drying wind, and facing the almost daily threat of freeze and storm?

Alpine plants, through their design and growing habits, have adapted themselves to the rigorous demands of this climate in many ways. Most plants are perennial: there just aren’t enough days or nutrients available for the growing of entire plants each year from seed. And they have the ability to grow and carry on photosynthesis at temperatures just above freezing, thus extending their season. In this zone, temperatures are rarely above 15° C; the mean summer temperature is about 10° C. But a flower such as the alpine buttercup, which is found at treeline or above, can grow through several centimeters of snow; heat given off during the plant’s respiration will create an opening through which it can emerge.

Plants have various adaptations to meet the demands of the alpine environment. Yellow stonecrop, not restricted to this zone, is nevertheless able to survive here because of its fleshy succulence and a waxy covering that prevents water loss. On some plants, protective hairs covering leaves and stems help retard the burning effects of wind and sun. Often this pubescent foliage looks more grey than green, for the soft hairs mute the color.

Cushion growth is another alpine adaptation. The moss campion cushion, covered with delicate pink flowers, grows to about one-third of a meter across and only 3 to 5 centimeters high. Spreading out close to the ground, the plant avoids the major violence of the wind and hoards moisture like a sponge.

The dryad, growing abundantly on the windy sweep of Siyeh Pass, shows alpine adaptations in several ways. The energy of the mature plant is channeled primarily into reproduction: its large flower, supported by a short stem, matures quickly; and it produces many seeds, ensuring germination of a few. An evergreen, it begins to synthesize water and carbon dioxide into food as soon as the snow is gone; and its rolled leaves prevent rapid evaporation. It grows as a low and woody mat that year by year extends itself through the production of new shoots that carpet the rock. Mat growth has the advantageof retaining dead plant material and capturing wind-blown grains of soil, allowing the plant slowly to enlarge its soil base.

Compared to the forest, the heartbeat of the tundra is painfully slow. Here a plant may grow for a quarter of a century before it has acquired the reserves necessary for flowering. Contrasted with the progress on the tundra, forest succession races by with dizzying speed. Yet imperceptible as the change may be the alpine plant community also passes from pioneer to climax.

Beyond the limit of other plants, lichens thrive, encrusting rocks with their rainbow colors. A lichen is actually a primitive and highly successful association between a fungus and an alga, working together for mutual benefit. The fungus protects the delicate alga, trapping and holding moisture; the green alga, in turn, produces enough food to sustain the needs of the fungus.

Generating rock-disintegrating acids that help secure this partnership to the rock, lichens, along with physical weathering, help break down the rocks into soil particles. Collected in pockets by run-off or wind, rudimentary soil is slowly invaded by cushion plants. After centuries of colonization by these, while the meager soil is deepened and enriched and moisture retention is increased, other plants move in, climaxing at last in hardy grasses and sedges. As in the forest, pioneer species change the environment to their detriment, creating a habitat better suited to other species.

Although it will progress with geologic slowness, the rocky ground of Siyeh Pass—its plant cover presently scant and wind-rowed by frost-heave and relentless wind—will in time develop grasses and sedges, the climax vegetation of the alpine meadows.

■Simplicity rules the alpine zone. Here life is reduced to bare essentials. Chief controlling force is climate; but the plants and animals that live here are well adapted. Compared to the lower realms, where both competition and predation are fierce, life here looks secure.

There is a penalty to simplicity. In the lowland, the long food chains and diversity of species, the long growing season, and the abundant food supply give the forest an adjustment mechanism and healing power not found on the critically balanced tundra. The greater the variety in a plant and animal community, the greater the stability. So in the alpine world there exists a paradox: the most durable life forms constitute the most fragile community.

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