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 )

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) BREEDS: northeastern Siberia, northern Alaska, arctic Canada, and northern Greenland. WINTERS: mainly from southern British Columbia south to California; along Gulf coast from Veracruz, Mexico, and Texas to western Florida; on Atlantic coast, New Jersey to South Carolina; casual in Hawaii (Godfrey 1966, Pratt et al. 1987). In recent years, a growing segment of western arctic population wintered in middle Rio Grande valley and Pecos River valley in New Mexico and to lakes in northern Chihuahua (and in southeastern Colorado in some mild winters) (Johnson and Herter 1989, Taylor and Kirby 1990).

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

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

Length: 71 cm

Weight: 3450 grams

• Terrestrial
• Freshwater
• Marine

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

Comments: Winters in both freshwater and coastal wetlands, wet prairies and extensive sandbars, foraging also in pastures, cultivated lands and flooded fields (AOU 1983). Nests in tundra marshes near water, on raised hummocks and ridges. In Manitoba, geese nesting in tall willows had better reproductive success than did geese nesting in shorter willows or in areas without willows (Jackson et al. 1988). Females generally nest at their natal or prior nest site.

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: Yes. At least some populations of this species make annual migrations of over 200 km.

Migrates north in March and April, arrives in breeding areas in May or early June. Migrates south August-November. Generally retraces in fall routes used in spring. Geese that nest near Hudson Bay generally winter along the coast of Texas and Louisiana; those that nest in the central Canadian arctic usually winter in Texas, New Mexico, and Mexico; nesters from western Canadian arctic usually winter in valleys of California and in New Mexico and Mexico; those that nest on Wrangel Island winter in and around Fraser and Skagit river deltas in British Columbia and Washington, respectively, and also in valleys of California (Johnson and Herter 1989, which see for many further details on migration). The Arctic coastal plain of northeastern Alaska and Yukon is an important staging (feeding) area for most of the western arctic population. Most depart northern staging areas in the Beaufort Sea area by October. Subspecies Atlanticus apparently makes only one stop (St. Lawrence River estuary) during spring migration; this is an essential area for accumulating the fat reserves needed for migration and especially reproduction (Gauthier et al. 1992); marshes of St. Lawrence estuary also are used for 5-7 weeks in fall. Males pair with females on mixed wintering grounds and accompany female to her natal or previous nesting area.

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 )

Comments: Browses on grasses; eats grains; uproots sedges, marsh grasses, and aquatic plants (eats stem, rhizomes, roots, bulbs). During initial part of breeding period uses nutritional reserves accumulated in winter and in staging areas.

Anser caerulescens are considered to be overabundant and as a result have been stripping their habitat of its vegetation.

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:

• artic foxes (Vulpes lagopus)
• jaegers (Stercorarius)

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 21 - 300

>1,000,000 individuals

Comments: Breeding population estimated at around 5 million in 1997 (Mowbray et al. 2000).

Mortality is highest in young; annual adult survival around 80%; few live beyond 10-15 years (Auk 109:731-747). See McLandress (1983) for nest density dynamics. Mean home ranges during brood-rearing varied from 6.6 to 21.7 square kilometers (Hughes et al. 1994).

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

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).

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 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: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization (Internal )

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)

Eggs are laid in June-July (sometimes late May); mainly early June in Beaufort Sea region, mid-June at Bylot Island; females arrive in nesting areas carrying well-developed eggs. Usually 4-5, sometimes 3-8, eggs incubated by female for 23-25 days (also reported as 20-23 days). Male stands guard. Young can fly at 38-49 days. Families usually break up by next nesting season. Some females begin nesting when two years old, years, most nest when three years old, and some delay breeding until they are at least four years old (Viallefont 1995, Auk 112:67-76). In Manitoba, females aged 5-7 years produced greater proportion of offspring than did younger or older mothers (Ratcliffe et al. 1988). Food availability in spring staging areas and weather during early nesting season may affect reproductive output. Incubating females take recesses to feed, especially in the third week (Reed 1995, Condor 97:993-1001). Does not renest if clutch destroyed or lost. Nesting colonies may number 1200 pairs per square mile. Mean clutch size decreased as population size increased in Manitoba colony (Cooch et al. 1989). Some females lay eggs in nests of other conspecifics.

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

Canada

Rounded National Status Rank: N2N,N5B : N2N: Imperiled - Nonbreeding, N5B: Secure - Breeding

United States

Rounded National Status Rank: N5B,N5N : N5B: Secure - Breeding, N5N: Secure - Nonbreeding

Rounded Global Status Rank: G5 - Secure

Global Short Term Trend: Increase of 10 to >25%

Comments: Most populations currently increasing; in North America, numbers have tripled since 1973 (Mowbray et al. 2000). Population indices for different populations were stable or increasing during 1980s (USFWS 1988). Breeding population at La Perouse Bay, Manitoba, increased from about 2000 pairs to 10,000 pairs between 1969 and the late 1980s (Cooch et al. 1991). Population on Howe Island near Prudhoe Bay, Alaska, increased from 39 nesting pairs in 1980 to 412 pairs in 1993; immigration was a significant factor (Johnson 1995). See Johnson and Herter (1989) for information on status in Beaufort Sea region. Wintering population of Snow/Ross' goose in central New Mexico increased greatly from 1976 to 1985, causing problems for crane management (Taylor and Kirby 1990).

Global Long Term Trend: Unknown

Comments: Huge numbers reported historically, but no quantified data available to establish trends. Since 1960s, numbers have been growing exponentially throughout most of range (Mowbray et al. 2000).

Comments: While on fall staging areas, susceptible to disturbances by low-flying aircraft and other human activities (see Johnson and Herter 1989).

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

Comments: Considered by some authors to be in the genus Anser (Howard and Moore 2003; Sibley and Monroe 1990). Blue morph and white morph formerly were regarded as distinct species, C. caerulescens and C. hyperborea. See Cooke et al. (1988) for evidence of former allopatry of white and blue forms; recent merging of the two probably was due to change in winter feeding habits that allowed birds of both morphs to meet in rice-growing areas of inland Texas and Louisiana. Infrequently hybridizes in the wild with C. rossii, Branta canadensis, and Anser albifrons (AOU 1983). Many waterfowl authorities suggest merging the genus Chen into the genus Anser (Livezey 1986). Despite female natal philopatry, mtDNA markers show no clear distinctions between nesting populations across the species' range from Wrangel Island (eastern Asia) to Baffin Island in the eastern Canadian Arctic (Avise et al. 1992).