Snow goose | |
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White morph | |
Blue morph | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Anseriformes |
Family: | Anatidae |
Genus: | Anser |
Species: | A. caerulescens |
Binomial name | |
Anser caerulescens | |
Subspecies | |
Snow goose range: Breeding range (also in northwest Greenland and Wrangel Island, Russia; not shown) Wintering range | |
Synonyms | |
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The snow goose (Anser caerulescens) is a species of goose native to North America. Both white and dark morphs exist, the latter often known as blue goose. Its name derives from the typically white plumage. The species was previously placed in the genus Chen, but is now typically included in the "gray goose" genus Anser . [2] [3]
Snow geese breed north of the timberline in Greenland, Canada, Alaska, and the northeastern tip of Siberia, and spend winters in warm parts of North America from southwestern British Columbia through parts of the United States to Mexico. [4] Snow goose populations increased dramatically in the 20th century.
In 1750 the English naturalist George Edwards included an illustration and a description of the snow goose in the third volume of his A Natural History of Uncommon Birds. He used the English name "The blue-winged goose". Edwards based his hand-coloured etching on a preserved specimen that had been brought to London from the Hudson Bay area of Canada by James Isham. [5] When in 1758 the Swedish naturalist Carl Linnaeus updated his Systema Naturae for the tenth edition, he placed the snow goose with the ducks and geese in the genus Anas . Linnaeus included a brief description, coined the binomial name Anas caerulescens and cited Edwards' work. [6] The snow goose is now placed in the genus Anser that was introduced by the French zoologist Mathurin Jacques Brisson in 1760. [7] [8] The scientific name is from the Latin anser, "goose", and caerulescens, "bluish", derived from caeruleus, "dark blue". [9] The snow goose is the sister species to Ross's goose (Anser rossii). [10]
Two subspecies are recognised: [8] [11]
The greater snow goose is distinguished from the nominate form by being slightly larger. It nests farther north and east. The lesser snow goose can be found in two color phases, the normal white-colored animals and a dark gray-colored "blue" phase. The greater snow goose is rarely seen in a blue phase. [12]
The snow goose has two color plumage morphs, white (snow) or gray/blue (blue), thus the common description as "snows" and "blues". White-morph birds are white except for black wing tips, but blue-morph geese have bluish-gray plumage replacing the white except on the head, neck and tail tip. The immature blue phase is drab or slate-gray with little to no white on the head, neck, or belly. Both snow and blue phases have rose-red feet and legs, and pink bills with black tomia ("cutting edges"), giving them a black "grin patch". The colors are not as bright on the feet, legs, and bill of immature birds. The head can be stained rusty-brown from minerals in the soil where they feed. They are very vocal and can often be heard from more than a mile away.
White- and blue-morph birds interbreed and the offspring may be of either morph. These two colors of geese were once thought to be separate species; since they interbreed and are found together throughout their ranges, they are now considered two color phases of the same species. The color phases are genetically controlled. The dark phase results from a single dominant gene and the white phase is homozygous recessive. When choosing a mate, young birds will most often select a mate that resembles their parents' coloring. If the birds were hatched into a mixed pair, they will mate with either color phase.
The species is divided into two subspecies on the basis of size and geography. Size overlap has caused some to question the division. [4] The smaller subspecies, the lesser snow goose (C. c. caerulescens), lives from central northern Canada to the Bering Straits area. The lesser snow goose stands 64 to 79 cm (25 to 31 in) tall and weighs 2.05 to 2.7 kg (4.5 to 6.0 lb). The larger subspecies, the greater snow goose (C. c. atlanticus), nests in northeastern Canada. It averages about 3.2 kg (7.1 lb) and 79 cm (31 in), but can weigh up to 4.5 kg (9.9 lb). The wingspan for both subspecies ranges from 135 to 165 cm (53 to 65 in).
Long-term pair bonds are usually formed in the second year, although breeding does not usually start until the third year. Females are strongly philopatric, meaning they will return to the place they hatched to breed.
Snow geese often nest in colonies. Nesting usually begins at the end of May or during the first few days of June, depending on snow conditions. The female selects a nest site and builds the nest on an area of high ground. The nest is a shallow depression lined with plant material and may be reused from year to year. After the female lays the first of three to five eggs, she lines the nest with down. The female incubates for 22 to 25 days, and the young leave the nest within a few hours of hatching.
The young feed themselves, but are protected by both parents. After 42 to 50 days they can fly, but they remain with their family until they are two to three years old.
Where snow geese and Ross's geese breed together, as at La Pérouse, they hybridize at times, and hybrids are fertile. Rare hybrids with the greater white-fronted goose, Canada goose, and cackling goose have been observed. [4]
Snow geese breed from late May to mid-August, but they leave their nesting areas and spend more than half the year on their migration to-and-from warmer wintering areas. During spring migration (the reverse migration), large flocks of snow geese fly very high and migrate in large numbers along narrow corridors, more than 3,000 mi (4,800 km) from traditional wintering areas to the tundra.
The lesser snow goose travels through the Central Flyway, Mississippi Flyway, and Pacific Flyway across prairie and rich farmland to their wintering grounds on grassland and agricultural fields across the United States and Mexico, especially the Gulf coastal plain. The larger and less numerous greater snow goose travels through the Atlantic Flyway and winters on a relatively more restricted range on the Atlantic coastal plain. Traditionally, lesser snow geese wintered in coastal marsh areas where they used their short but strong bills to dig up the roots of marsh grasses for food. However, they have also since shifted inland towards agricultural areas, likely the cause behind the unsustainable population increase in the 20th century. This shift may help to contribute to increased goose survival rates, leading to overgrazing on tundra breeding grounds. [13]
In March 2015, 2,000 snow geese were killed in northern Idaho from an avian cholera epidemic while flying their spring migration to northern Canada. [14]
The snow goose is a rare vagrant to Europe, but escapes from collections have occurred, and it is an occasional feral breeder. Snow geese are visitors to the British Isles where they are seen regularly among flocks of brant, barnacle goose, and greater white-fronted goose. There is also a feral population in Scotland from which many vagrant birds in Britain seem to derive.
Around 2015, a small group of 3-5 snow geese landed on the north shore of O'ahu. They were seen and photographed several times over the course of 3-4 months.
In Central America, vagrants are frequently encountered during winter. [15]
Outside of the nesting season, they usually feed in flocks. In winter, snow geese feed on left-over grain in fields. They migrate in large flocks, often visiting traditional stopover habitats in spectacular numbers. Snow geese frequently travel and feed alongside greater white-fronted geese; in contrast, the two tend to avoid travelling and feeding alongside Canada geese, which are often heavier birds.[ citation needed ]
The population of greater snow geese was in decline at the beginning of the 20th century, but has now recovered to sustainable levels. Snow geese in North America have increased to the point where the tundra breeding areas in the Arctic and the saltmarsh wintering grounds are both becoming severely degraded, [16] and this affects other species using the same habitat.
Major nest predators include Arctic foxes and skuas. [17] The biggest threat occurs during the first couple of weeks after the eggs are laid and then after hatching. The eggs and young chicks are vulnerable to these predators, but adults are generally safe. They have been seen nesting near snowy owl nests, which is likely a solution to predation. Their nesting success was much lower when snowy owls were absent, leading scientists to believe that the owls, since they are predatory, were capable of keeping competing predators away from the nests. A similar association as with the owls has been noted between geese and rough-legged hawks. [17] Additional predators at the nest have reportedly included wolves, coyotes and all three North American bear species. [18] [19] Few predators regularly prey on snow geese outside of the nesting season, but bald eagles (as well as possibly golden eagles) will readily attack wintering geese.
The breeding population of the lesser snow goose exceeds 5 million birds, an increase of more than 300% since the mid-1970s. The population is increasing at a rate of more than five percent per year. Non-breeding geese (juveniles or adults that fail to nest successfully) are not included in this estimate, so the total number of geese is likely higher. Lesser snow goose population indices are the highest they have been since population records have been kept, and evidence suggests that large breeding populations are spreading to previously untouched sections of the Hudson Bay coastline. The cause of this overpopulation may be the heavy conversion of land from forest and prairie to agricultural usage in the 20th century.
Since the late 1990s, efforts have been underway in the U.S. and Canada to reduce the North American population of lesser snow and Ross's geese to sustainable levels due to the documented destruction of tundra habitat in Hudson Bay and other nesting areas. The Light Goose Conservation Order was established in 1997 and federally mandated in 1999. Increasing hunter bag limits, extending the length of hunting seasons, and adding new hunting methods have all been successfully implemented, but have not reduced the overall population of snow geese in North America. [20] [21]
This section includes a list of references, related reading, or external links, but its sources remain unclear because it lacks inline citations .(October 2021) |
The late 1990s was when the mid-continent population of snow geese was recognized as causing significant damage to the arctic and sub-arctic breeding grounds which was also causing critical damage to other varieties of waterfowl species and other wildlife that uses the arctic and sub-arctic grounds for home habitat. The increase in population in substantial amounts raised concern to then DU chief biologist Dr. Bruce Batt who was part of a committee that put together various data and submitted it to the U.S. Fish and Wildlife Service and the Canadian Wildlife Service with the recommendation on ways to combat the growing population and the damage that the snow geese were creating in the arctic breeding grounds.
The committee recommended relaxing hunting restrictions and giving hunters a better opportunity to harvest more snow geese on their way back to the breeding grounds in the spring. The suggested restrictions were to allow the use of electronic callers, unplugged shotguns, extended shooting hours, and no bag limits. Two years after the Light Goose Conservation Order was introduced it was federally mandated in 1999.
The greylag goose or graylag goose is a species of large goose in the waterfowl family Anatidae and the type species of the genus Anser. It has mottled and barred grey and white plumage and an orange beak and pink legs. A large bird, it measures between 74 and 91 centimetres in length, with an average weight of 3.3 kilograms. Its distribution is widespread, with birds from the north of its range in Europe and Asia often migrating southwards to spend the winter in warmer places, although many populations are resident, even in the north. It is the ancestor of most breeds of domestic goose, having been domesticated at least as early as 1360 BCE. The genus name and specific epithet are from anser, the Latin for "goose".
The greater white-fronted goose is a species of goose that is closely related to the smaller lesser white-fronted goose. The greater white-fronted goose is migratory, breeding in northern Canada, Alaska, Greenland and Russia, and winters farther south in North America, Europe and Asia. It is named for the patch of white feathers bordering the base of its bill: albifrons comes from the Latin albus "white" and frons "forehead". In the United Kingdom and Ireland, it has been known as the white-fronted goose; in North America it is known as the greater white-fronted goose, and this name is also increasingly adopted internationally. Even more distinctive are the salt-and-pepper markings on the breast of adult birds, which is why the goose is colloquially called the "specklebelly" in North America.
The taiga bean goose is a goose that breeds in northern Europe and Asia. It is migratory and winters further south in Europe and Asia. This and the tundra bean goose are recognised as separate species by the American Ornithological Society and the International Ornithologists' Union, but are considered a single species by other authorities. The taiga and tundra bean goose diverged about 2.5 million years ago and established secondary contact c. 60,000 years ago, resulting in extensive gene flow.
The pink-footed goose is a goose which breeds in eastern Greenland, Iceland, Svalbard, and recently Novaya Zemlya. It is migratory, wintering in northwest Europe, especially Ireland, Great Britain, the Netherlands, and western Denmark. The name is often abbreviated in colloquial usage to "pinkfoot". Anser is the Latin for "goose", and brachyrhynchus comes from the ancient Greek brachus "short" and rhunchos "bill".
The lesser white-fronted goose is a goose closely related to the larger greater white-fronted goose. It breeds in the northernmost Palearctic, but it is a scarce breeder in Europe, with a reintroduction attempt in Fennoscandia.
The Canada goose, sometimes called Canadian goose, is a large wild goose with a black head and neck, white cheeks, white under its chin, and a brown body. It is native to the arctic and temperate regions of North America, and it is occasionally found during migration across the Atlantic in northern Europe. It has been introduced to France, the United Kingdom, Ireland, Finland, Sweden, Denmark, New Zealand, Japan, Chile, Argentina, and the Falkland Islands. Like most geese, the Canada goose is primarily herbivorous and normally migratory; often found on or close to fresh water, the Canada goose is also common in brackish marshes, estuaries, and lagoons.
The greater scaup, just scaup in Europe or, colloquially, "bluebill" in North America, is a mid-sized diving duck, larger than the closely related lesser scaup and tufted duck. It spends the summer months breeding in Iceland, east across Scandinavia, northern Russia and Siberia, Alaska, and northern Canada. During the winter, it migrates south to the coasts of Europe, eastern Asia, and North America.
The emperor goose, also known as the beach goose or the painted goose, is a waterfowl species in the family Anatidae, which contains the ducks, geese, and swans. In summer, the emperor goose is found in remote coastal areas near the Bering Sea in arctic and sub-arctic Alaska and the Russian Far East, where it breeds in monogamous pairs. It migrates south to winter in ice-free mudflats and coasts in Alaska, mostly the Aleutian Islands, and Canada's British Columbia, rarely reaching the contiguous United States. Listed as near threatened by the International Union for Conservation of Nature, the species' population is declining due to threats such as pollution, hunting, and climate change.
Ross's goose, formerly Chen rossii, is a white goose with black wingtips and a relatively short neck. It is the smallest of the three white geese that breed in North America. It is similar in appearance to a white-phase snow goose, but about 40% smaller. Other differences from the snow goose are that the bill is smaller in proportion to its body and lacks "black lips". Like snow geese, Ross's geese may exhibit a darker "blue" phase or morph, though this is extremely rare.
The cackling goose is a species of goose found in North America and East Asia.
The brant or brent goose is a small goose of the genus Branta. There are three subspecies, all of which winter along temperate-zone sea-coasts and breed on the high-Arctic tundra.
Anser is a waterfowl genus that includes the grey geese and the white geese. It belongs to the true goose and swan subfamily of Anserinae under the family of Anatidae. The genus has a Holarctic distribution, with at least one species breeding in any open, wet habitats in the subarctic and cool temperate regions of the Northern Hemisphere in summer. Some also breed farther south, reaching into warm temperate regions. They mostly migrate south in winter, typically to regions in the temperate zone between the January 0 °C (32 °F) and 5 °C (41 °F) isotherms.
The Atlantic Flyway is a major north-south flyway for migratory birds in North America. The route generally starts in Greenland, then follows the Atlantic coast of Canada, then south down the Atlantic Coast of the United States to the tropical areas of South America and the Caribbean. Every year, migratory birds travel up and down this route following food sources, heading to breeding grounds, or traveling to overwintering sites.
The San Luis National Wildlife Refuge Complex is located in the northern San Joaquin Valley, within Merced County and Stanislaus County of California. The complex, with four federal National Wildlife Refuges, is managed by the U.S Fish & Wildlife Service.
Hagerman National Wildlife Refuge (HNWR), a haven for migratory birds and other wildlife, lies in northwestern Grayson County, Texas, on the Big Mineral Arm of Lake Texoma, on the Red River between Oklahoma and Texas. This National Wildlife Refuge is made up of water, marsh, and upland habitat. Visitors can hike, observe wildlife, hunt, and fish throughout the year.
The Merced National Wildlife Refuge encompasses 10,262 acres (41.53 km2) of wetlands, native grasslands, vernal pools, and riparian areas in California. It was established in 1951 under the Lea Act to attract wintering waterfowl from adjacent farmland where their foraging was causing crop damage. In the last few decades, changes in agricultural practices and refuge management have reduced these wildlife/crop issues.
The Arctic Goose Joint Venture (AGJV) is a conservation partnership established in 1989 between governments, organizations, and conservation groups to coordinate research and monitoring of Arctic, sub-Arctic and boreal nesting goose populations of North America, specifically the cackling goose, Canada goose, emperor goose, greater white-fronted goose, Ross's goose, and snow goose. Executing Arctic research expeditions in collaboration with partners is a primary goal of the venture, so that the logistics of such research can be coordinated efficiently. One of its main activities is to collar geese in Canada, the United States, and other nearby Arctic areas, such as Wrangel Island of Russia.
The bean goose is a goose that breeds in northern Europe and Eurosiberia. It has two distinct varieties, one inhabiting taiga habitats and one inhabiting tundra. These are recognised as separate species by the American Ornithologists' Union and the IOC, but are considered a single species by other authorities, such as the British Ornithologists' Union. It is migratory and winters further south in Europe and Asia.
The dusky Canada goose is a subspecies of the Canada goose. They are the darkest variant, similar to the Pacific cackling goose. Tagged dusky geese have red bands with white letters on them attached to their neck. They represent one of the smallest populations of Canada goose in the Pacific Northwest. Due to the species' minimal population and exclusive breeding grounds, the dusky Canada goose is a species of interest to the Pacific Flyway Council and the U.S. Forest Service. The Cordova Ranger District, on the Chugach National Forest, has been working since 1984 to implement a monitoring and restoration program for the geese.
The Canadian Low Arctic Tundra ecoregion covers a rolling landscape of shrubby tundra vegetation along the northern edge of the mainland Canada along the border of the Northwest Territories and Nunavut, and a small portion in Quebec on the northeast coast of Hudson Bay. The region is important for large herds of caribou and other large mammals, and for large nesting colonies of birds such as snow geese. The region is mostly intact, with 95% remaining intact.
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