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.
– Feeding Habits
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.
– Feeding Habits
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.
– Feeding Habits
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.
Adult bald eagles (Haliaeetus leucocephalus) have a blackish-brown back and breast, a white head, neck, and tail, and yellow feet and bill. Juvenile bald eagles are a mixture of brown and white, with a black bill in young birds. The adult plumage develops when they become sexually mature at about four or five years of age. One way to determine the sex of an eagle is to examine its beak; females have deeper beaks (distance from top to chin) than males. The bald eagle is the only eagle confined to North America, and when trying to spot it, keep in mind that there are no other large black birds in North America with white heads and tails.
Female bald eagle measures 35 to 37 inches in length, slightly larger than the male, with a wingspan that varies from 79 to 90 inches. The male bald eagle has a body length measuring from 30 to 34 inches, and its wingspan ranges from 72 to 85 inches. Bald eagles weigh between 10 and 14 pounds, and northern birds are significantly larger than their southern relatives. Wild bald eagles may live as long as 30 years, but the average lifespan is probably about 15 to 20 years.
All eagles are renowned for their excellent eyesight, and the bald eagle is no exception. Bald eagles, like all birds, have color vision. Their eyes are almost as large as a human’s, but their sharpness is at least four times greater. These birds have two foveae, or centers of focus, that allow them to see both forward and to the side at the same time.
Bald eagles are capable of seeing fish in the water while soaring several hundred feet above them. This is quite an extraordinary feat, since most fish are counter-shaded, meaning they are darker on top and thus harder to see from above. It is also thought that a bald eagle could identify ground prey, such as a rabbit, moving almost a mile away, which means that flying at an altitude of 1,000 feet, it could spot prey over an area of almost three square miles from a fixed position.
Bald eagles have 7,000 feathers arranged in layers, which are hollow and lightweight, yet extremely strong and highly flexible. Under the outer layer of feathers is an inner layer of down or smaller feathers. They protect the bird from the cold, as well as the heat of the sun by trapping layers of air. Overlapping feathers can form a dense covering, which the birds can open or close at will; to maintain its body temperature, an eagle simply changes the position of its feathers.
Their feathers enable eagles to live in extremely cold environments. In fact, eagles do not have to migrate to warmer areas each year to fulfill temperature requirements; they only migrate to available food supplies. While an eagle suns itself on a cold morning, it ruffles and rotates its feathers so that the air pockets are either opened to the air or drawn together to reduce the insulating effect. Feathers also provide waterproofing and protection and are crucial for flight.
Eagles’ wings are long and broad, making them effective for soaring. To help reduce turbulence as air passes over the end of the wing, the tips of the feathers are tapered so that when the eagle fully extends its wings, the tips are widely separated. To help them soar, eagles use thermals – rising currents of warm air and updrafts generated by terrain, such as valley edges or mountain slopes. Soaring is accomplished with very little wing flapping, enabling them to conserve energy. Long-distance migration flights are accomplished by climbing high in a thermal, then gliding downward to catch the next thermal, where the process is repeated. Several eagles soaring in a thermal together is described as a ‘kettle of eagles.’
Shrill, high-pitched screeches and twittering are common descriptions used for bald eagle vocalizations. Eagles do not have vocal cords, but sound is produced by the syrinx – a bony chamber located where the trachea divides to go to the lungs. Bald eagle calls may be a way of reinforcing the bond between the male and female, and to warn other eagles and predators that an area is defended.
– Feeding Habits & Home Range
The bald eagle is primarily a fish eater, although it will take whatever prey is available and easiest to obtain, including carrion. In addition, the bald eagle will steal food from other eagles, as well as other species. Chasing another raptor is usually enough to persuade the other bird to drop its kill, but occasionally, the eagle will attack. When grabbing prey, a bald eagle’s lifting power is about four pounds. Upon spotting a fish swimming near the surface of the water, the eagle approaches it in a shallow glide and snatches it out of the water with a quick swipe of its talons. To prevent dropping a catch, these talons have a special locking mechanism – when the open talons hit the prey, they instantly close and cannot be opened again until the eagle pushes down on a solid surface.
When eating, an eagle can consume one pound of fish in about four minutes. Bald eagles have an out pouching of the esophagus, called a crop, where they can store food when the stomach is full. The crop also separates indigestible substances, such as feathers, fur and scales, from the meat. These waste materials are mixed with mucus and formed into a mass, which after the meal, is eventually regurgitated and cast out.
Because of their size, bald eagles have few enemies and require a large hunting area. The hunting area or home range patrolled by a bald eagle varies from 1,700 to 10,000 acres, but are smaller where food is present in large quantities. Because of the energy expended during hunting, an eagle must spend a lot of time resting quietly. It is estimated that only 1 out of 18 attacks are successful.
– Breeding & Young
Bald eagles reach sexual maturity at around four or five years of age. At that time, an eagle begins to focus its energy on finding a mate and raising offspring. During the breeding season, both birds will protect the nest territory from other eagles and predators. Bald eagles mate for life, but when one dies, the survivor will not hesitate to accept a new mate.
In Alaska, bald eagle mating season occurs from late March to early April. These birds are capable of breeding annually from the age of four, but some of the adults, though paired, seem to choose not to do so. This may be an instinctive decision based on the weather, availability of nesting sites or food. Because an eagle lives up to 30 years in the wild, it has many years in which to produce offspring necessary to replace itself.
Bald eagles lay between one and three eggs during the month of May. Five to ten days after a successful copulation, the female lays a speckled, off-white or buff colored egg. The second egg is laid a few days later, followed by a possible third. The 35 days of incubation duties are shared by both parents, but it is the female who spends most of her time on the nest. During incubation, one parent is always on the nest, not only to keep the eggs warm, but also to protect them from predators, which will break open and eat the eggs.
Trading places on the nest can be a tense time, as the brooding parent may have to call for relief, or may be reluctant to leave and have to be pushed off the eggs or young. During incubation, the male bald eagle regularly brings sprigs of conifer branches to the nest. It is not known exactly why this is done, but it may be to deodorize the nest or to provide shade for the eaglets.
Eggs hatch in the order in which they were laid. Eaglets break through the shell by using their egg tooth, a pointed bump on the top of the beak. It can take between 12 and 48 hours to hatch after making the first break in the shell. Once the eggs begin to hatch, the female’s vigilance becomes nearly constant, and the male provides the majority of the food needed by his rapidly growing family. Eventually the female will take up her share of the hunting, but in the early days, all of her attention is given to the young eaglets in the nest. Unfortunately, however, only a few of the eggs hatched in a lifetime will survive to old age.
The golden eagle is North America’s largest predatory bird. With its six-foot wingspan and effortless soaring flight, this powerfully built species is an impressive and beautiful sight. Golden eagles are distinguishable from other birds of prey by their great size and flat profile of head and bill. Adults are largely dark brown, except for a golden area near the crown, nape, and sides of the neck and face, which give the bird its common name. The tail is grayish brown.
From below, the large flight feathers of the wings appear to be brownish gray, while the head, body and smaller feathers on the forepart of the open wings are blackish. The eyes of adult golden eagles are dark brown, and the bills and claws are black, with a yellow cere and feet. The legs are feathered all the way down to the toes.
Golden eagles range in length from 27 to 35 inches and have long, broad wings, with a wingspan measuring from six to over seven feet. Males and females are similar in appearance, but females are much larger than males. Females range in weight from 8.6 to 13.5 pounds, whereas males range from 6.6 to 12 pounds.
Juvenile golden eagles appear similar to adults, except for light patches on the tips of the wings, and a wide white band on the tail and a terminal band of black. This plumage is sometimes referred to as its ‘ringtail’ plumage as a result of these bands. Juveniles attain adult plumage between ages four and six years.
– Geographic Location
Golden eagles (Aquila chrysaetos) have a holarctic distribution. They occur throughout Eurasia, in northern Africa and in North America. In North America, golden eagles are found primarily in the western half of the continent, from Alaska to central Mexico, with small numbers in eastern Canada and scattered pairs in the eastern U.S.
– Habitat & Home Range
Golden eagles are found in open and semi-open areas, from sea level to over 11,000 feet in elevation. Preferred habitats include tundra, shrublands, grasslands, woodland-brushlands, and coniferous forests. Most golden eagles are found in mountainous areas, but they also nest in wetland, riparian, and estuarine regions.
Golden eagle home range sizes vary with season and quality of habitat. During the breeding season, golden eagles in the western U.S. have home ranges encompassing between 7 and 13 square miles.
– Feeding Habits
The diet of this species is composed primarily of small mammals such as rabbits, hares, ground squirrels, prairie dogs, and marmots. Golden eagles also eat other birds, reptiles and fish in smaller numbers, and occasionally capture large prey, including ungulates, coyotes, and badgers. They have also been known to capture large flying birds like geese or cranes. A pair of eagles will often hunt together; one chases the prey to exhaustion, and the other swoops down for the kill. Golden eagles rarely cache prey for later consumption.
Some populations of golden eagles are sedentary, while others are migratory. In North America, most golden eagles in Alaska and Canada travel south in autumn when the food supply on their northern range begins to decline. Most pairs that breed in the continental U.S. and southern Canada remain in the same area year-round.
Golden eagles are generally solitary or in pairs, though non-mated juveniles may be found in groups. Wintering adults may also be found in groups during times of extreme weather or very abundant food.
Golden eagles can carry up to eight pounds during flight. They can fly up to 80 miles-per-hour, though the average speed is 28 to 32 miles-per-hour, and may reach speeds up to 200 miles-per-hour in a dive. In flight, golden eagles hold their wings horizontal to the body, rather than at an angle, as many other hawks and vultures do. They fly with slow, powerful wing beats alternated with gliding and soaring.
Golden eagles are mostly silent, except during the breeding season. They use nine different calls to communicate, most of which appear to be associated with food delivery to nestlings. Golden eagles are not thought to use vocalizations to mark their territory. Instead, they use an undulating flight to defend its boundaries.
Golden eagles are monogamous and may maintain pair bonds for several years. In non-migrant populations, pairs appear to stay together year-round. For migratory golden eagles, pair formation and courtship begin when the eagles return to the breeding grounds, between February and mid-April; there is no information available regarding whether these pair bonds are maintained throughout the year. Courtship activities in this species include undulating flight by one or both members of the pair, chases, dives, mock attacks, presenting talons, soaring together, and circling.
Golden eagles breed once yearly, from March through August, depending on their geographic location. Golden eagle pairs in much of the range are sedentary, remaining in the same territory year-round. Pairs may begin nest-building and courtship as early as December and may have several nests in their breeding territory, which are often re-used year after year, refurbished before the onset of each new breeding season. Golden eagles usually build their nests on cliffs, but may also use trees, riverbanks, and man-made structures, such as windmills and electrical towers. Both the male and female of a pair refurbish or build the nest, which may take four to six weeks. Nests are constructed of sticks and local vegetation and are lined with soft vegetation, including shredded yucca, grasses, dry leaves, inner bark, mosses, and lichens. Nests may be huge if the site allows – the largest nest on record measured 20 feet tall and 8.5 feet wide.
One to four (usually two) eggs are laid, with three- to four-day intervals between each egg. The female begins incubating after the first egg is laid and is responsible for most of this process, though the male often takes part. The eggs are dull white and spotted, or blotched with brown or reddish brown. Incubation lasts for 35 to 45 days, and the young hatch several days apart and are altricial. The older nestlings are usually much larger than the younger nestlings, and the older, stronger eaglets often kill their smaller siblings.
The chicks are brooded by the female with decreasing frequency for approximately 45 days. Both parents bring food to the nestlings, which begin to leave the nest between 45 and 81 days of age by walking, hopping or falling out of the nest. They begin to fly around 10 weeks of age, and become independent from the parents 32 to 80 days after fledging. Juveniles do not breed until age four to seven years, after attaining adult plumage.
The oldest known golden eagle lived to 46 years of age in captivity. In the wild, golden eagles have been known to live up to 32 years.
Golden eagles have few predators. There is no record of predation of golden eagle eggs, and wolverines and grizzly bears are the only recorded predators of nestlings.
– Conservation Status
The golden eagle is federally protected under the Bald Eagle Protection Act of 1962. In some parts, a decline of golden eagle populations has been recorded. Washington and Montana list it as a species of special concern, and Maine, New Hampshire and New York recognize it as an endangered species. But in other areas they are common, and populations are presumably stable.
Previous to the Protection Act of 1962, some 20,000 golden eagles were killed, mostly from aircraft, because they were thought to prey on young sheep and goats. But studies in towns where sheep are raised found no evidence to support such claims, as almost 70 percent of the eagle diet consisted of rabbits. Many golden eagles have been electrocuted in power lines, caught in steel traps set for coyotes and other animals, and poisoned by ranchers. Direct and indirect human-caused mortality, disturbance, and elimination of prey by habitat alteration are the main factors limiting their populations. Recreational activities may also disturb breeding, migration, and wintering behaviors. Golden eagles are likely to abandon nests during incubation if they are disturbed.