The tundra can be vibrant with life in summer and hauntingly desolate in winter. The harshness of the Arctic climate, the poverty of its soil, and the exceedingly long and dark winters are incredibly hostile to life. But, as philosopher Spinoza remarked, “Nature abhors a vacuum.” Although the opportunities are few and fraught with hardship, some animal species have managed to adapt to life in the Arctic. Their ability to survive the cold and often marginal food conditions has been honed to the utmost perfection.
Of the world’s 4,600 mammal species, about 40 live in the Arctic, and nearly half of those are sea mammals. The Arctic and Antarctic Seas are astoundingly rich in nutrients, more so than all other seas on earth, and are home to millions of seabirds, seals, and whales–the largest creatures this world has ever known.
There are about 9,600 species of birds in the world, yet in the immensity of the Arctic, only about 100 species breed here. Most are migrants who come north during the short, but food-rich summer, raise their broods and flee south at the approach of winter; fewer than 10 bird species live here year-round. Of the world’s more than 750,000 insect species, less than 1,000 occur in the far north; of the roughly 30,000 species of fish, less than 100 live in the northern seas, lakes and rivers. There are no reptiles that exist in the Arctic, and although several species of toads and frogs inhabit the boreal forest belt, no amphibian ventures north of the treeline.
In the fall, all life in the Arctic prepares itself for the inevitable coming of winter. Compelled by special hormones, migratory birds feed almost incessantly to accumulate the fat reserves that will fuel their long flight south. Ground squirrels, who have nearly doubled their weight since spring, busily stock winter dens with food supplies. Barren ground grizzlies are swathed in fat so thick, it will sustain them through their long winter hibernation until spring. Arctic foxes cache surplus food–lemmings or young birds–to ease winter’s hardship.
Char, the large, far-northern fish who have feasted all summer at sea, return in the fall to the lakes where they will spawn. Historically, Inuit, the indigenous peoples of the Arctic, would spear them and store large quantities of the fat fish as food for winter. The caribou are well provisioned in the fall as well; about one-fifth of their total weight is comprised of fat. Even plants store lipids in their roots and rhizomes for that magic moment nine months later when winter will yield again to spring and instant, rapid growth will be imperative.
Insects can neither flee, like birds, from the Arctic winter, nor shield themselves, like mammals, with thick layers of fat and fur. Instead, they produce within their bodies a glycerol-like antifreeze so efficient, they are able to survive temperatures as low as –70 degrees Fahrenheit. The insects spend winter in suspended animation and resume life nine to ten months later when the warmth of spring awakens them.
As winter approaches, birds become more and more agitated. Increasingly cold temperatures, as well as shortening days and declining food sources, trigger “zugunruhe”–what ornithologists call the nearly febrile restlessness that grips them just prior to migration. Dense groups of knots zigzag into the sky, flashing alternately in red and brown as all birds of the flock turn abruptly in unison. Old squaws gather in large rafts and swim, neatly spaced and aligned, back and forth along the coast. Nervous, twittering flocks of snow buntings drift like snowflakes across the land. Skeins of snow geese wing purposefully south. Each day more birds depart, and the snow and silence once again descend upon the North.
Ptarmigan, ermine, and foxes change color into their winter white, as do the hares of the lower Arctic, which are an earthy brownish-gray in summer. In the far North, where summer lasts barely two months, Arctic hares remain white year-round. They also have some very peculiar habits not shared by their more southerly cousins. In late fall and winter, they gather in large flocks. When alarmed, these hares bolt upright, and as biologist David Gray observed, bounce “up and down on tiptoe while assessing the danger,” then bound away on long hind legs in rapid kangaroo-like leaps.
All animals produce heat by releasing the energy stored in their food, particularly in lipids, proteins, and carbohydrates. The normal body temperature of mammals hovers around 100°F (100.8°F in polar bears, 101.2°F in musk oxen, 98.6°F in humans), and these temperatures are constant and vital. When the air temperature is low enough to sap an animal’s body heat faster than it can be generated, its core temperature is lowered and thus, the animal is put in immediate danger. A naked, hairless man (the least adapted of Arctic animals) exposed to temperatures of –40°F and winds of 30 mph (conditions common in the Arctic) will die in about 15 minutes. The Inuit avoided this fate by dressing in the skins of the Arctic’s superbly cold-adapted creatures.
Animals living in the Arctic have two ways of coping with the cold: 1) They can increase their metabolic rate (their internal heat production) by eating large amounts of food, and 2) They can prevent loss of body heat through insulation. A 70-pound sea otter eats about 15 pounds of sea urchins, mollusks, and fish on a daily basis. Given the chance, a polar bear can devour 100 pounds of high-calorie blubber at one meal. Wolves, after a successful hunt, consume a quarter of their body weight in food. Ptarmigan are forever busy snipping buds and shoots; in order to stay alive through the winter, they require a daily food intake roughly equal to one-fifth of their body weight. But there is obviously a limit as to how much food an animal can consume to stoke its body’s furnace, and for survival in this icy realm, animals rely more upon heat conservation than on heat production. Their insulation–fat, fur, or feathers–effectively shields them from the cold and enables them to live in the arctic environment.
The following is a brief introduction to some of the wildlife that we may encounter during our Polar Bears of Churchill expedition.
Sometimes called “the deer of the North,” the caribou, more than any other animal, is the symbol of the North country. No other large North American mammal carries out such extensive and spectacular migrations or occurs in such vast herds as does the caribou. This gregarious creature of the wide-open spaces is equally at home on the tundra, taiga or in the boreal forest.
For centuries, entire cultures have relied on caribou as a source of food and clothing. An abundance of caribou meant feasts and good times, while a shortage meant famine and real hardships. Although traditional behavior often determined the migration routes and seasonal ranges used by caribou, the species was, and still is, no more predictable than the wind.
There are three subspecies of caribou in North America. The least plentiful is the Peary caribou–a small white animal that spends the entire year on the treeless tundra of the Canadian high Arctic. In contrast, the barren ground caribou is the most plentiful and the one forming the large herds that migrate each year between the tundra and the trees. The third subspecies is the woodland, or mountain, caribou. It does not form vast herds or make extensive migrations. Rather, woodland caribou spend most of the year in smaller groups that move between the boreal forest and open mountain habitats.
Physical Characteristics & Arctic Adaptations
Caribou are the only deer in which both males and females have antlers. Antler shape varies greatly, and it is said that no two are the same. The large antlers typical of adult bulls are shed in early winter, while the cows keep theirs until calving time the following June. This allows the pregnant females to claim and defend the best feeding areas in late winter when they need high quality food to nourish their rapidly growing fetuses.
There are several important adaptations that allow caribou to survive, and even thrive, during the long and cold winters. To prevent excessive heat loss from its long legs, the caribou maintains two internal temperatures. Its body temperature remains near 105°F, while that of its legs is more than 50 degrees cooler. The caribou’s veins and arteries are closely aligned, like cables in a conduit, so that the out-flowing arterial blood transmits its warmth to the chilled venous blood returning from the limbs. Constriction of blood vessels in the extremities permits a flow of blood just sufficient to keep the legs from suffering frost damage, ensuring at the same time that little of their precious body heat is lost to the icy ambient air.
The caribou’s compact body is covered by a warm, hollow-haired coat that protects it from extreme temperatures. Even the muzzle, tail, and feet are well furred. Caribou hairs are club-shaped–thicker at their tips than at their base–and form a densely packed outer layer with myriad tiny air spaces near the skin and within the fine, curly under wool. In addition, the long guard hairs are filled with air cells. This deep-pile coat is so warm, it renders caribou virtually impervious to the worst Arctic weather. In fact, caribou are so well adapted to their Arctic environment that some scientists call them chionophiles, or “snow lovers.”
In addition, the large feet of the caribou act almost as snowshoes and help the animals to ‘float’ on soft snow; the characteristic clicking sound made by moving caribou comes from their tendons slipping over the bones in their feet. The broad, sharp-edged hooves easily break and clear snow when caribou crater for food.
Caribou have a keen sense of smell that they use for detecting danger, as well as for locating food under the snow cover. In fact, the name caribou comes from the Micmac word xalibu, meaning “the pawer,” which describes the animal’s habit of digging through the snow for food. In winter, caribou are the only animals that can live almost exclusively on lichen. In summer, their diet is more varied and includes forbs, grasses, sedges, and willows. Mushrooms also become a favorite with caribou when they are available in August.
Caribou are frequently seen along the coast during the summer. Here, they spend considerable time on the tidal flats in an effort to escape the ever-present black flies. With the approach of fall, the caribou, now sleek with fat from reindeer moss and other lichens, sedges, and marine plants, prepare for the rigors of the coming winter. Mating now occurs, with caribou calves being born during late May and June.
Biologists have named most of the major caribou herds after the geographical locations of their calving grounds. It is towards these remote areas in which they were born that the pregnant cows trek so urgently in spring. Accompanied by yearling calves, the females march 15 to 20 miles each day, probably guided across this vast and seemingly featureless land by clues and memories retained from past migrations. The bulls, which have no pressing date with destiny, follow far behind the herds of females at a more leisurely pace.
Once they reach the calving ground, the cows disperse. In the preceding fall, most females mated nearly at the same time, and now, in mid-June, most calves are born within a five-day span. This reproductive synchrony has great survival value; following the birth of the calves, the herds can quickly regroup and few stragglers are left behind. To caribou, there is safety in numbers.
While the nearly simultaneous birth of the calves has many advantages, it also exposes them to great danger as well. If during this vital, five-day period a late-season blizzard blankets the land, or worse, freezing rain drenches the calves’ fur, destroying their insulation, the just-born fawns may die. In favorable years, calves constitute as much as 25 percent of a herd, and less than 5 percent in disaster years.
Apart from man, wolves are a caribou’s main predators. Wolves are master strategists and have the ability to hunt as a skillful team. They can kill healthy caribou in a relay chase or cunning ambush, but they prefer, since it requires less effort and energy, to cull from a herd its most vulnerable and easily caught members–the old, the young, the weak and the sick; laggers and strays are also favored victims.
To many natives of the North, the inland Inuit of Canada and Alaska, and to such indigenous groups as the Chipewyans and the Naskapi of Labrador, the caribou once meant life. They ate its meat, dressed in its fur, and from its antlers and bones they made tools, toys, and weapons. The Naskapi, said explorer W.B. Cabot who visited them in 1906, were “lords over their fine country, asking little favor, ever, save that the deer (caribou) may come in their time.”
Once, the caribou may have numbered about three million. As recently as the 1940s, Canadian biologist C.H.D. Clarke said, “it is to be hoped that there will never be so few caribou that it will be possible to count them.” But soon, scientists were counting and recounting them, and each successive census showed more starkly the havoc wrought by uncurbed and excessive hunting. “In just ten years, between 1965 and 1975,” noted biologist George Calef, “Alaska lost over half its caribou.” The Kaminuriak herd of the Canadian North shrank from more than 150,000 in the 1950s to less than 40,000 now; other once-vast herds declined nearly as rapidly, victims of unbridled and often wasteful hunting.
The ringed seal is the most abundant, widespread, and important seal to the socio-economy of the people in the Northwest Territories. It is the most common seal of the Arctic, with a population that may total six or seven million. This seal is found throughout the circumpolar regions of the Northern Hemisphere, and its preferred habitat consists of the leads, pressure ridges, and polynyas in the land-fast ice of the Arctic Ocean.
Ringed seals are small compared to other seal species; males are usually about 4.5 feet long and weigh between 145 and 200 pounds, while females tend to be a bit smaller, averaging 100 to 110 pounds. Their coats are made of stiff guard hairs and occur in various color patterns, which are basically light gray in color, with black spots surrounded by lighter ring markings (hence their name). On their backs, the spots are often confluent, giving the appearance of a dark stripe. Underneath, the coat is lighter, and their bellies are often a clear silvery-white to creamy yellow, with a scattering of black spots.
The ringed seal’s senses of vision, hearing, and smell are well developed. Their vocalizations include whines, moans, and growls. These creatures are curious and may investigate unfamiliar sights or sounds; basking seals constantly alternate between lifting their heads up for about seven seconds, and laying flat for 26 seconds, and they often heed warnings from other seals.
As with most seals, physiological adaptations, such as a high red blood cell count, the ability to reduce their heart rate from 80-90 to 10-20 beats per minute, and control over the blood flow to vital organs, have enabled ringed seals to make deep and sustained dives. Feeding dives average about three minutes, with one and a half minutes spent at the surface. Their maximum diving potential is about 295 feet in depth and 45 minutes in duration. Ringed seals dive vertically, tail first, rarely exposing their backs.
Primarily solitary creatures, ringed seals occasionally travel in loosely organized groups. They tend to form aggregates at haul-out areas such as ice cracks. Segregation by age occurs in winter when adults remain in their preferred breeding habitats under stable ice in bays and fiords, and non-breeders are found at the floe edge and move in response to food availability and population pressures.
While in the water, seals use breathing holes within the ice that are maintained by clawing the ice with their fore flippers. Before surfacing, a seal may blow bubbles into the hole to test for predators. The breathing hole is usually cone-shaped and is covered with an ice dome punctured by a small vent. If snow drifts over the hole, a lair may be hollowed out of it.
Food, while in shore, consists largely of polar cod and bottom-dwelling crustaceans, like mysis shrimp. Offshore, the seals feed on planktonic crustaceans, notably the amphipod shrimp parathemisto. Fasting occurs during the breeding, molting, and basking periods.
Sexual maturity in the ringed seal occurs between the ages of five and ten. After ten years of age, females have a high annual pregnancy rate. Breeding males can be identified by their strong, musky odor and their territorial behavior. The peak of mating activity occurs in April, and the embryo development is delayed for 81 days, followed by a nine-month gestation period.
Newborn pups average about two feet in length and ten pounds in weight. When one year old, they are about 70 percent of their mature size. Seal pups are usually born on stable ice in a snow den from mid-March to early April. The female will find a natural snow cave or excavate a birth lair in a snowdrift over a breathing hole. The den provides protection and warmth for the single pup during a five- to eight-week nursing period. Only the female seal will care for the pup, and she subsequently abandons it when the ice breaks up. Large numbers of seals can be observed basking on the ice at this time, usually in late June or early July.
The pup is born with a fine-textured, woolly white coat or ‘lanugo,’ which keeps the pup warm until it acquires an insulating layer of blubber; this lanugo is shed by the age of eight weeks. The molted pup, called a “silver jar,” has a silvery belly and a dark gray back of fine hair.
There are many predators of ringed seals, including polar bears, Arctic foxes, walrus, wolves, dogs, wolverine, sharks, gulls, and humans; about 26 percent of the pups in their dens are eaten by Arctic foxes. Ringed seals are the main prey of polar bears, which will catch one seal about every five and a half days.
The bearded seal is a primary food source for polar bears and for the Inuit of the Arctic coast. Holding a place of esteem in the area, the native name for the seal is ugyuk or oogrook, and its skin is used to cover traditional wood-frame boats, known as umiaks. The bearded seal gets its generic name from two Greek words that refer to its heavy jaw. In addition, the seals name refers to its most characteristic feature: conspicuous and very abundant whiskers.
The bearded seal is a fairly large animal, with both sexes reaching over seven feet in length and weighing about 573 pounds. They are grayish in color, darker on the back, with a scattering of rather small dark spots. As the name suggests, the bearded seal has long whiskers covering its nose and chin. Each whisker is smooth along its length, and not beaded, as they are on other seals (except monk seals, which also have smooth whiskers). Another characteristic that bearded seals share with monk seals is the presence of four nipples–other seals have only two.
Bearded seal pups are born in a grayish brown lanugo, with scattered patches of white on the back and crown. Births take place on pack ice between mid-March and early May, and the lactation period lasts for about 12 to 18 days.
Habitat & Feeding Habits
The bearded seal has a circumpolar distribution that corresponds closely to that of the ringed seal–it is found all along the European, Asiatic, and American Arctic coasts and their associated islands. It is essentially, however, an Arctic and sub-Arctic seal of relatively shallow waters. The world population has been estimated to be between 600,000 and one million.
Bearded seals feed on shallow water benthic organisms, bottom-dwelling mollusks, crustaceans, sea cucumbers, and fishes.
Few animals make their home in the harsh environment of the Arctic. An exception is the Arctic fox, an adaptable circumpolar specialist. The size of a large house cat, the Arctic fox is one of the smallest mammals to remain active above the snow surface during the long, northern winter.
Wrapped in long, dense, silky-soft fur, Arctic foxes appear rounded and bulky in winter. But beneath this warm and voluminous coat lies a somewhat scrawny body, only weighing 10 pounds on average. Adaptations like short ears, legs, and muzzle, and thickly furred footpads, enable it to maintain its body temperature despite temperatures of –20°F and lower. Like other canines, the Arctic fox has a keen sense of smell and acute hearing. This combination helps it detect lemmings, a major food source, moving about under the snow. It is a better swimmer than other canines, an asset for an animal that lives on the coast and offshore ice. The Arctic fox has a characteristically high-pitched bark, and it has also been known to purr like a cat.
Arctic foxes are dimorphic, meaning that there are two color phases among them–white and brown. In both phases, the fox changes color from summer to winter. The Arctic fox is the only canine that undergoes this seasonal color change. For the white fox, by the beginning of July, molting reveals its brown and fawn-colored summer fur. About eight weeks later, the white winter coat begins to grow in again. Blue phase foxes are a dark bluish in summer and pale gray in winter. For reasons not yet understood, the ‘coastal’ foxes of such regions as West Greenland, Jan Mayen Island, the Pribilof Islands, and the Commander Islands are nearly always blue, while 99 percent of Canada’s ‘continental’ foxes are white.
Arctic foxes live both a communal and nomadic life, often forming small bands to scavenge the countryside for food. They do not hibernate during the winter months. Foxes also construct dens, often in cliffs at least a mile apart, which are inhabited by a family social group. This group consists of one adult male, the litter, and two vixens–one of which is a non-breeding female born the previous year that stays to help care for the next litter.
An Arctic fox generally makes its den in a low mound, 3 to 13 feet high, in the open tundra, or in a pile of rocks at the base of a cliff. These dens have between four and eight entrances and a system of tunnels covering about 323 square feet. Some of these dens have been used for centuries by generations of foxes.
The Arctic fox reaches sexual maturity in as little as 10 months. Arctic foxes are monogamous and usually mate for life, and mating typically occurs in February or March. Shortly after mating, each pair begins to search for a natal den, which will help to ensure the survival of their pups. But suitable den sites are hard to find, as permafrost must be far enough below the surface to permit burrowing. Births take place from April through June for the first litter, and during July or August for the second litter. The average gestation period lasts about 49 to 57 days, and the number of young per litter varies with the availability of food, especially lemmings.
The usual litter size is 5 to 8 cubs, although as many as 25 have been known to be born at one time. Blind, deaf, and toothless, a newborn pup weighs no more than a tennis ball, but it has a voracious appetite. The young are weaned at about two to four weeks of age, where they will emerge from the den. The male parent will stay with the cubs, helping to feed them. He then mates with the female again just a few weeks after the first litter is born.
Natal dens are usually abandoned by the end of August when the family splits up. Each fox then embarks on a solitary search for food. Hunting takes place from dusk to dawn. Even when the summer sun shines 24 hours a day, the foxes continue to hunt during the nighttime hours. The Arctic fox is an opportunistic feeder, eating practically any animal, alive or dead. Although it prefers small mammals, it will eat insects, berries, carrion, and even the stool of animals or human beings. Generally, its winter diet consists of marine mammals, invertebrates, sea birds, fish, and seals. In the summer, for populations living more inland, the diet consists mostly of lemmings.
The provident foxes prepare for the long, lean winter by storing food during summer’s brief season of plenty. During the summer months, when food is much more readily available, the Arctic fox collects a surplus amount of food and carries it back to its den, where it is stored under stones for later use. Danish scientist Alwin Pedersen once found a fox’s cache that contained 36 dovekies, two young murres, four snow buntings, and a large number of dovekie eggs. “The frozen bodies of the birds were neatly arranged in a long row…and the eggs were heaped in a pile. The whole store would have provided food for a fox for at least a month.”
Arctic fox numbers rise and fall in a more-or-less regular cycle lasting three to five years. This cycle is related to changes in the lemming population. When food is scarce, foxes are known to migrate–some for hundreds, even thousands of miles.
The Struggle For Survival
Arctic foxes have a high mortality rate. Parents frequently abandon their young, and aggressive pups are known to kill their littermates. In addition to starvation, rabies is a major cause of death in adult foxes. The virus for this fatal disease is found in up to 20 percent of the population. The incidence of rabies increases during the periods of food scarcity, presumably because of lowered resistance. Although the Arctic fox has a potential ten-year lifespan, only 1 in 25 will live past its fourth year.
The diversity of birds that occurs in the coastal region is amply demonstrated by the fact that, exclusively around the town of Churchill, close to 200 species have been observed. It is apparent from observations on the breeding and staging grounds that the coastline environment is exceedingly important to bird reproduction.
“In the Arctic, July is summer,” said explorer-writer Peter Freuchen, laconically and with some truth. In the far North, this is the only month when the average temperature is above freezing. June is typically fair, but often fickle. In early July, the tundra is spangled with flowers. A month later, the tiny petals have paled, shriveled, and dropped; in August, summer’s fleeting glow is rapidly fading.
Because summer is so desperately short, the fervid exaltation of spring is glorious, but brief. There is no time for leisurely dalliance, for all must try to raise a new generation within summer’s short span. In May, young ravens are already hatched. Lemming mothers nurse their second or third litter of the year in clefts and niches among the rocks. Snow buntings incubate their eggs in deep-supped grass nests, warmly lined with hairs and feathers. Some birds in warmer lands raise two or more broods during summer’s long sway. For birds nesting in the Arctic, however, raising just one brood is a race against time, for their young must be ready to fly and flee before the onset of winter.
The willow ptarmigan, the pigeon-sized grouse of the North, is a stocky, chicken-like bird, with a small black bill and short, rounded wings. It is the largest of the three ptarmigan species, growing to a length of 15 to 17 inches. Males weigh just over a pound, while females are a bit lighter. These birds are also distinguished by the red comb over the eye and a squarish tail that is black year-round. Adult males have bright red “eyebrows”; females are more gray-brown and more heavily barred on the breast and flanks.
The willow ptarmigan’s nostrils are hidden by dense feathers that keep out snow in winter; their legs are also covered with feathers. In the fall, ptarmigan even grow a dense mat of stiff feathers on their toes. During the winter, these feathered feet serve as snowshoes, while long, sharp claws help the bird to walk over icy slopes. Among other bird species, only the snowy owl is as well prepared for the harsh Arctic winters.
The plumage of the ptarmigan is in constant harmony with the prevailing colors of the land. Ptarmigan are snowy white in winter and piebald in late spring, which is part winter’s white and part summer’s brown. They assume rich earthy hues of brown and gray in summer, become speckled gray, white, and brown in fall, and resume their dazzling white when snow covers the land again.
Ptarmigan seem to be aware of their natural camouflage, and in turn, prefer to remain in surroundings in which they are less noticeable to predators. White ptarmigan are extremely loath to cross dark ground, and birds in summer brown avoid patches of snow. As a result, ptarmigan are inconspicuous at all times of the year, except in spring when the cocks ardently court the females.
The preferred summer habitat for this species is open tundra, as well as mountain slopes and the upper edge of timberline. In winter, willow ptarmigan seek shelter in valleys and willows. They can be found throughout most of their range during the winter; however, populations go through cycles of abundance and scarcity, similar to other members of the grouse family. When willow ptarmigan are very abundant, flocks migrate southward. In fact, willow and rock ptarmigan are perhaps the most migratory of North American upland game birds.
Willow ptarmigan spend most of their time on the ground, but when startled, they explode into strong, rapid flight and may travel up to a mile before landing. In addition, among other strange sights of the Arctic, one may observe a ptarmigan flying directly into a snow bank, which is its preferred method of going to sleep. It is much warmer sleeping under the snow, which offers great insulation, than on top of it, and of course, it is also harder for predators to find them hidden underneath. This is why ptarmigan fly into their beds; if they walked, a fox or other predator might follow their tracks.
In the summer, willow ptarmigan eat tender leaves and flower buds of willows, birches, and alders. They also eat blueberries, crowberries, cranberries, the fruit of kinnikinnicks, and insects. In winter, they eat willow twigs and buds, as well as catkins and buds of dwarf birches and other trees and shrubs. Chicks eat will eat caterpillars, other insects, and spiders.
Each cock establishes a territory that he defends furiously against the incursions of other males. Near the female, he struts, burps, and clucks, the serrated combs above his eyes glowing in brilliant vermilion. With wings akimbo, stiff and dragging, and his tail fanned so that its black rectrices flash out in startling contrast to the encompassing white, he pursues the female with mincing, urgent steps. He suddenly soars aloft with a sharp clatter of wings, then drifts down towards the female with an excited, gurgling song.
Males may engage in fierce battles that leave them with plucked feathers and flowing blood. Nearby, the females wait. Willow ptarmigan are typically a polygamous species–a male may mate with several females. After mating, each hen makes a nest on the tundra, on a beach, or near a marsh. She scrapes a cavity at the base of a log, bunch of grass, bush, or hummock, and then lines it with grasses and feathers.
Unlike other ptarmigan, male willow ptarmigan remain with the females during incubation. They hide in nearby thickets, rushing out to defend the hen from predators. Male ptarmigan may knock intruding gulls over, and one was even observed attacking a grizzly bear! Males will also attack people who try to catch their chicks.
The hen incubates the eggs for 21 or 22 days. Soon after hatching, the chicks leave the nest. When just one week old, they begin making their first short, jumping flights. Both parents attend the chicks until they are at least 60 days old.
This white, dusky-flecked bird usually measures between 24 and 29 inches in length, and weighs just over three pounds. These powerful birds are the largest species in the Arctic and have an average wingspan of five and a half feet. There is sexual size dimorphism within this species, where the female is usually larger and heavier than the male.
These birds are predominantly white in color, with dark brown bands across their plumage; this band is more prevalent among the young. These bands are not as noticeable on male birds, and in many cases, older males will be completely white. Their eyes are yellow and their legs and feet are covered in white feathers, which help to protect them from the cold Arctic weather.
Snowy owls are carnivorous. They commonly hunt by utilizing an elevated perch, affording them good visibility while waiting for potential prey to appear in the hunting area. Their visual scanning of the hunting area is facilitated by their ability to swivel their head three quarters of the way around (270 degrees).
Snowy owls’ main food sources are typically lemmings and mice. They also will take rabbits, seabirds, and fish opportunistically. These owls of the North are powerful hunters. They kill ptarmigan, murres, and eiders, they snatch char and trout from river shallows, and although the snowy owl weighs only about three pounds, it can catch and kill a 12-pound Arctic hare.
Courtship begins in mid-winter and can last through March or April. Male snowy owls will strut around with their wings spread open to impress the females. Males may also catch food and deliver it to the females as a sign of being a good provider. In some areas, snowy owls will nest with the same mate for many years, even for life. Others will only stay together for one nesting season.
As mentioned earlier, lemmings are a snowy owl’s staple fare. The presence or absence of lemmings stimulates or inhibits the female owl’s fecundity. In years of lemming scarcity, she lays only two or three eggs, or may not breed at all. In peak lemming years, the owl’s clutch is large, and as many as 15 eggs have been recorded.
The female snowy owl begins to incubate as soon as the first egg is laid, and she will typically lay five to eight eggs. Eggs are white and are laid every other day. They are incubated by the female and hatch after 32 to 34 days. Hatching is not synchronous; with a chick hatching every other day, in large nests there can be great differences among chicks in age and size. Latecomers are often doomed, as the older owlets will likely trample them in their eagerness to obtain food. The young that die are usually eaten by the mother, or she may feed them to their stronger, more fortunate siblings.
Both male and female feed and protect the chicks, which are covered with snowy white down. After about three weeks, the owlets, downy gnomes with bright yellow eyes, leave the nest and scatter. At this point, the young are unable to fly; they do not truly fledge until 50 to 60 days of age. The young owlets seem forever hungry, and they wheeze loudly and insistently whenever they spot a parent carrying food. With winter only weeks away, there is an intense urgency in the young to feed and grow, and to become independent from parental care.