Anser caerulescens are known for their loud squawking and honking but no real studies have been done to determine the meanings, if any, of their vocalizations.
Communication Channels: acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
The population size of Anser caerulescens is increasing at an estimated rate of 130,000 birds per year. Periodic hunting seasons have been established to help curb the growing population. There are restrictions, however, that protect snow geese from overhunting and efforts have been made to protect critical habitat in Canada and the United States.
US Migratory Bird Act: protected
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
There are three stages of development in Anser caerulescens. There are the hatchlings and young, the juvenile non-breeders, and the adult breeders. The young grow rapidly and are fully fledged within forty-five days. They reach maturity in two years, which is when they usually pair up in a monogamous relationship with another Snow Goose. The pair begins to breed for the first time in June of the third year (Belrose 1976).
In recent decades many snow geese have become agricultural pests. They sometimes opt for easy food supplies found in farm fields with tender shoots and wasted corn, wheat, and oats.
Negative Impacts: crop pest
Because of their large numbers the snow geese are hunted, although there are restrictions in place in order to protect the species from over hunting.
Positive Impacts: food
Anser caerulescens are considered to be overabundant and as a result have been stripping their habitat of its vegetation.
Anser caerulescens are herbivorous; they eat roots, leaves, grasses, and sedges. They have strong bills for digging up roots in thick mud. Their most common food source in the northern breeding grounds is American bulrush. As they migrate south they feed on the aquatic vegetation in wetlands and estuaries. They also forage in agricultural fields for wasted oats, corn and winter wheat. They eat tender shoots as they come up or feed on grass, weeds, and clover. In their Louisiana wintering grounds they feed on wild rice. Snow geese also need some sort of grit such as sand or shell fragments to aid in their digestion.
Foods eaten include: saltgrass, wild millet, spikeruch, feathergrass, panic grass, seashore paspalum, delta duckpatato, bulrush, cordgrass, cattail, ryegrass, wild rice, berries, aquatic plants and invertebrates, and agricultural crops.
Animal Foods: insects
Plant Foods: leaves; roots and tubers; seeds, grains, and nuts; fruit
Primary Diet: herbivore (Folivore )
Anser caerulescens have quite an expansive geographical range. They leave their wintering grounds in March and head north over the New England states. They rest between the first week in April and the end of May in the St. Lawrence River area. They then continue northward over central Quebec, Canada to their destination in the northeast artic. The breeding grounds cover the area from northern Baffin Island, west to Bathurst Island, north to Alert on Ellesmere Island, and east to northwest Greenland. The southwest coast of Bylot is the location of the main nesting colony. They leave their breeding grounds in September. They begin to arrive at the St. Lawrence River area in October and stay until early November when they continue to their American wintering grounds(Heyland, 2000). Their main wintering grounds are along the gulf coast of Louisiana and Texas between the Mississippi delta and Corpus Christi, Texas. However, in recent years colonies have been seen in Missouri, Illinois, Kansas, Oklahoma, Nebraska, and Iowa. Smaller numbers are found in eastern Mexico and southern New Mexico (Belrose, 1942).
Biogeographic Regions: nearctic (Native )
The breeding grounds of Anser caerulescens consist of low grassy tundra with flat basins within 10 km of lakes, rivers, flood plains, or seas. Some choose rockier terrain near grassy wet tundra and flat marshy areas protected from the north by mountains. Overall they prefer coastal lagoons, marshes, tidal flats, and estuaries, but have been known to take advantage of prairies and agricultural lands.
Habitat Regions: temperate ; polar ; terrestrial
Terrestrial Biomes: tundra ; savanna or grassland
Wetlands: marsh
Other Habitat Features: agricultural ; estuarine
The actual lifespan of Anser caerulescens is unknown, however, it is believed they have quite long lifespans. It was reported in one case that a goose was banded in 1957 and killed fifteen years later by a hunter. Annual mortality is between 25 to 50 percent and depends on age and breeding status.
Average lifespan
Status: wild: 19.5 years.
Average lifespan
Status: wild: 24.5 years.
Average lifespan
Status: wild: 26.6 years.
Anser caerulescens stand 63.5 to 78.7 cm tall (and average 70 cm in length) with wing lengths varying from 400 to 450 mm. They weigh from 2 to 3 kg. Males and females are similar in appearance although males are usually larger. There are two phases seen in Anser caerulescens called the "snow" phase and the "blue" phase. In the adult "snow" phase the body is a snowy white with black wing tips. They have red feet and legs, a pink bill, and a black "grin patch" (the black patch of skin that surrounds the base of the bill, which resembles a smile). The adult blue phase geese have the same feet, legs, bill, and grin patch, but they have blue/gray bodies with black wing tips. They also have white necks and heads, and some white on the underside of their bellies. In the immature snow phase the body is a dirty white color with black wing tips and in the immature blue phase they are a slate gray with little or no white. In both immature phases they have red feet and legs but they are not as bright as the adult goose. It was once thought that the two different color phases were different species, but they are not. They interbreed with one another, and they are found together through out their geographical ranges. The colors are genetically controlled and when selecting mates they tend to choose a mate that resembles their parents. Individuals with a mixed set of parents will breed with either color phase.
Range mass: 1606 to 3307 g.
Average length: 70 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry ; polymorphic
Sexual Dimorphism: sexes alike; male larger
Major predators include artic foxes (Vulpes lagopus) and gull-like birds called jaegers (genus Stercorarius). 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, which lead scientists to believe that the owls, since they are predatory bird, were capable of keeping predators away from the nests (Tremblay et al., 1997).
Known Predators:
Anser caerulescens are monogamous and usually form long-term pair bonds.
Mating System: monogamous
Anser caerulescens actually mate with their monogamous partners during their migration back to the artic tundra. Nesting occurs in June; nesting colonies can number in the tens of thousands. The geese begin building nests approximately ten days after arriving at the nesting site. They usually make shallow depressions in the ground and line them with bits of dry vegetation and down from the mother. The female will lay one egg a day until she reaches a full clutch of about 3 to 5. The eggs are incubated for 23 to 25 days while the male guards the nest and the mother. Young fledge in 45 to 49 days. Females reach sexual maturity between 2 and 4 years. Snow geese tend to nest near snowy owls, which are believed to deter predators from coming to the nests.
Breeding season: From April to June
Range eggs per season: 1 to 6.
Average eggs per season: 3-5.
Range time to hatching: 23 to 25 days.
Range fledging age: 45 to 49 days.
Range age at sexual or reproductive maturity (female): 2 (low) years.
Average age at sexual or reproductive maturity (female): 4 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); oviparous
Average eggs per season: 4.
Young snow geese are precocial and receive parental care from both the male and female parent.
Parental Investment: no parental involvement; precocial ; pre-fertilization; pre-hatching/birth (Protecting); pre-weaning/fledging (Provisioning: Male, Female)
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-grey 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.
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.
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]
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.
Anser caerulescens - MHNT
A. c. atlanticus, spring migration, blue morphs in foreground, Alexandria, Ontario
Wintering snow geese on Fir Island, Washington
Snow goose landing
Snow geese in a corn field on Fir Island, Washington in the Skagit River delta
Greater snow geese in flight
Snow geese (Anser caerulescens)
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.
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. Snow goose populations increased dramatically in the 20th century.
