Lesser Snow Goose

Each spring and fall undulating lines of brilliant white geese with black-tipped wings fly over southern Canada. The strength and beauty of these birds, as they wing their way between arctic breeding areas and temperate wintering habitat, bring pleasure to many people.

Most of the migrating white geese that are seen over southern Canada west of the province of Quebec are Lesser Snow Geese Anser caerulescens caerulescens, although smaller white geese, Ross' Geese Anser rossii, mingle with the prairie flocks. Migrating white geese seen in southern Quebec are more likely to be Greater Snow Geese Anser caerulescens atlanticus; however, some Lesser Snow Geese travel over the province with the flocks of greater snows and, along with them, break their migratory flights at Cap Tourmente on the St. Lawrence River. In the Atlantic provinces, migrating snow geese are seen only occasionally.

People who live in the lower mainland of British Columbia can not only see Lesser Snow Geese on migration, they can also observe the geese on their wintering grounds. This is because part of the large Lesser Snow Goose population that North America shares with eastern Asia winters in British Columbia's Fraser River delta — after breeding 4000 km away on Wrangel Island in the Soviet Arctic.

General appearance

The Lesser Snow Goose comes in two different colour phases. The plumage of white-phase geese is almost completely white, except for black wing tips. The blue-phase goose has a white head, a bluish colour on the feathers of the lower back and flanks, and a body that ranges in colour from very pale, almost white to very dark. Both the white- and blue-phase snow geese frequently have rusty orange faces, because their feathers have been stained by iron in the earth where the birds feed.

The goslings of the white-phase geese are yellow, those of the blue phase nearly black. By two months of age the young birds of both colour phases are grey with black wing tips, although the immature blue-phase birds are generally a darker grey and have some light feathers on the chin and throat, which can become stained like those of the adults. The goslings are still grey the following spring; in April and May they show white scapulars, white necks, and white secondary coverts, but they still have an overall grey wash.

By the spring the black to dark grey bills of the immature birds have become grey-pink. The bill of the adult is pink and is narrower than the broad, black bill of the Canada Goose, and it has evolved to enable the geese to eat the nutritious roots of marshland plants. The serrated edge of the bill makes the bird appear to be smiling and is sometimes called the "grinning patch."

The Lesser Snow Goose has a wingspan of about 90 cm and its average weight is 2.2-2.7 kg, the male being larger. The birds are usually seen in very large flocks and are always quite vocal. When flying they stay together in large groups but they do not generally fly in Vs like Canada Geese. Instead they form lines or Us that change shape frequently. Because of the apparent waving motion of the flying lines, snow geese are sometimes known as "wavies."

Related species

There are three kinds of white geese found in North America, the Lesser Snow Goose, Greater Snow Goose, and Ross' Goose. The Greater Snow Goose is slightly larger than the Lesser Snow Goose and nests farther north and east than the Lesser Snow Goose; blue-phase Greaters are rarely seen. The Ross' Goose is much smaller than the Lesser Snow Goose and does not have a grinning patch on the side of the bill. Blue-phase Ross' Geese are rare. As the numbers and ranges of both species have increased during the last 50 years, hybrids between them have become quite frequent. The hybrids are intermediate in size between Ross' Geese and Lesser Snow Geese.

Population size and distribution

Surprisingly, in an age of declining wildlife populations, Lesser Snow Geese have doubled in number in the past 15 years and, among North American geese, their numbers are second only to those of the Canada Goose. However, because there are many subspecies and races of Canada Geese, the Lesser Snow Goose can probably be considered the single most abundant goose in Canada. Currently, about 2 000 000 nest in Canada, along the coast of Hudson Bay, from Cape Henrietta Maria in Ontario to Keewatin; on Southampton Island; on southern Baffin Island; in northern Mackenzie and Keewatin south of Queen Maud Gulf; and on Banks Island. The other major concentration of breeding Lesser Snow Geese in the world is the one on Wrangel Island in eastern Siberia, where there are now about 100 000 birds.

Although most Lesser Snow Geese nest in Canada, only 20 000–40 000 winter in this country — in south-coastal British Columbia — and they originate on Wrangel Island. Birds nesting in the Canadian Arctic winter in central California, New Mexico, the interior highlands of Mexico, and along the Gulf of Mexico, both on the coast and, increasingly, in inland areas.

Migration routes

Because Lesser Snow Geese breeding in Canada are spread over such a vast area, they take many different routes between their breeding and wintering areas. Lesser Snow Geese breeding in the western Arctic form pre-migration staging flocks in the Mackenzie River delta and along the north coast of the Yukon and Alaska. On migration they fly up the Mackenzie River, through Alberta and western Saskatchewan and on to central California or the interior of Mexico.

Birds from the eastern Arctic stage in very large numbers in James Bay and on the west coast of Hudson Bay before heading farther south. During migration they pass through Manitoba and Ontario, on a rather broad front, en route to the coast of the Gulf of Mexico.

Major shifts in autumn distribution have taken place in prairie Canada since 1975. In that year 50 000–100 000 snow geese started to use a more westerly route through eastern Saskatchewan. The shift from southwestern Manitoba to eastern Saskatchewan has continued annually to 1988. This means that birds from the central Arctic fly in two directions: one southwestward corridor takes them into Alberta and western Saskatchewan and another south-eastern corridor through southern Manitoba.

Birds from Wrangel Island in Siberia fly across the Bering Strait to Alaska and down the west coast of British Columbia to major wintering areas on the Fraser River, the Skagit River in Washington, and in central California. Some, also bound for California, fly up the Mackenzie River and through Alberta.

We know less about the spring migration routes, which appear to be similar to those in fall, but with some shifts between corridors. Birds returning to Wrangel Island tend to fly along the British Columbia coast, but some of the Wrangel Island population also use an interior route through Montana, Alberta, Saskatchewan, Northwest Territories, and interior Alaska. Birds of western Canadian origin wintering in California fly north through Alberta, then down the Mackenzie valley to the western Arctic coast. Birds returning from the coast of the Gulf of Mexico fly up the Mississippi and Missouri River valleys to an important staging area southwest of Winnipeg and then in a more-or-less straight northeasterly line to James Bay and the Hudson Bay coast and north into the eastern Arctic.

Breeding behaviour

Lesser Snow Geese, unlike most other water-fowl, usually nest close to each other in large colonies with densities of up to 2000 pairs per square kilometre. When snow geese first return to their breeding colony the ground is often still snow-covered. But snow geese are well adapted to wait for the thaw of ice and snow in order to nest. In spring they carry heavy loads of fat and protein in their body reserves and can live on these for up to two weeks, though where possible they feed on emerging vegetation. As the snow begins to melt the flock breaks into smaller groups and eventually into pairs.

The nest itself consists of a scrape in the moss or gravel that often becomes built up into a mound over the years with bits of moss, willow, and grasses. Some down is added to the nest bowl as the eggs are laid. From two to six eggs are produced, with the average clutch size being around four. Incubation begins when the last egg is laid and continues for about 23 days. Only the female incubates. The male remains nearby to protect the female and nest from predators and from other geese looking for a ready-made home. The female leaves the nest for only a few minutes each day, and in the latter part of the incubation period she may not leave at all. As a result she is very thin by the time hatching begins; she may lose up to 30% of her body weight, which she regains when she starts to feed with the goslings.

Nesting starts as early in the spring as northern snow conditions allow and varies between colonies. Depending on latitude, egg-laying begins from late May to mid-June. If delayed by snow cover after 20 June, the geese do not breed; instead, they resorb their eggs and wait until the next year. Incubation starts about five or six days after the first egg is laid. The lapse of time varies according to the number of eggs produced, and peak hatching occurs between late June and mid-July, eggs in the more southern colonies generally hatching earlier than those in the north.

After hatching, the young geese must grow very quickly in order to be large enough to fly south before the Arctic winter returns. After all the young birds have hatched they may stay together in the nest for up to 24 h. When they have dried off they leave the nest, together with both parents, and begin to feed. Initially their diet consists mostly of insects, which are never scarce during summer in the Arctic. As they grow, their need for a high-protein diet dimin-ishes, and within about two weeks they have switched almost completely to grasses and sedges. From an initial weight of about 100 g at hatch the young grow to more than 1200 g in six to seven weeks. While the young are still small both adults moult their flight feathers, the males a week or so ahead of the females. Subadults and failed breeders moult two to three weeks before successful parents. Some goslings and their parents walk and swim up to 50 km during the eight-week period from hatching to fledging. Both the young and the adults must spend most of their time feeding in order to grow large enough to fly or to regain their flight feathers by mid-August. The family group gains its power of flight at the same time.

Snow geese show a very strong family bond. The young and adults remain together throughout the winter and the spring and fall migrations. The family generally breaks up when the parents start a new nest; however, sometimes the young of the previous year rejoin the new family.

Food habits

After the Lesser Snow Geese leave their Arctic breeding grounds they begin to make use of food sources other than grasses and sedges. On migration, pasture grasses, corn, and wheat increasingly form the main part of the diet, although birds migrating along the west coast still rely on traditional estuarine plants. During the winter on the Fraser River delta, the geese also feed on pasture grasses and fall rye. In wintering areas along the Gulf of Mexico, the birds have traditionally fed on tubers, roots, and grasses in coastal marshes; however, in about 1960, some of this wintering population began to feed farther inland on cultivated grain – both on fall-sown crops and on the waste grain left by bigger harvesting equipment. In spring, Lesser Snow Geese feed voraciously on grasses, weeds, forbs, and waste grain and put on much weight.

Because most marshland plants store their energy reserves in their roots in winter months, Lesser Snow Geese have evolved strong serrated bills to cut and tear the roots of bulrushes and sedges from the ground in coastal marshes. The goose holds the plants with the serrated edge so that its powerful, toughened tongue (also serrated along the margins) can cut through them.

Research and management

The Lesser Snow Goose is the most highly studied of the Arctic-nesting geese. Much has been learned about it, but there are still many things that are unknown. Its population has increased steadily over the last 40 years, probably for several reasons. The increase in winter food due to changing agricultural practices in the southern United States is probably the most important cause. Climatic changes in the Arctic may also have helped, earlier spring snow melt in the eastern Arctic having enabled the geese to occupy new areas on Baffin Island and on the mainland District of Keewatin. Another factor is the creation of new colonies in the eastern Arctic, which are far enough south so that breeding success is rarely prevented by persistent snow.

The increased population is creating problems both for the Lesser Snow Goose and for people. When large numbers of geese concentrate in relatively small areas, they may deplete their natural food supplies. At McConnell River, on the west coast of Hudson Bay, a colony of about 200 000 breeding geese has denuded the original nesting area of edible vegetation so that little more than bare soil remains. On some colonies, including a recently established one on Jenny Lind Island, there may be too many geese for the food resources available.

When the geese turn to agricultural crops in the south, they do not confine themselves to waste grains, but may cause damage to winter wheat and important grasslands. There is also the possibility of disease outbreaks when large numbers of birds are confined to small areas. Ir several recent years epidemics of avian cholera have killed many Lesser Snow Geese at spring staging areas in the central United States and in breeding colonies on the west coast of Hudson Bay, on Banks Island, and in the central Arctic.

Because of their abundance and wide distribution in southern Canada on fall migration and in the United States in the late fall and winter, many snow geese are shot by hunters. They are an important source of food for some northern people, especially the Cree Indians living around James Bay, at times when other sources of fresh meat are scarce or inaccessible. In 1988 recreational hunters reported taking about 70 000 Lesser Snow Geese in Canada and 270 000 in the United States.

Current research includes studies of the reproductive biology of the geese; of migratory routes, their use, and the timing of migration; and of food habits and the effects the geese have on the plants that constitute their food. Waterfowl managers are primarily concerned with the numbers of Lesser Snow Geese, the quantity and quality of habitat available to them throughout their life cycle, and the proportion of the population that is shot annually by hunters. High-level photography with ground truthing is used to estimate the size of breeding colonies once every four to six years.

Efforts are continually being made to protect critical habitats. Migratory Bird Sanctuaries have been set aside in the Northwest Territories to protect nesting colonies on the Anderson River delta, Kendall Island, Banks Island, the Queen Maud Gulf, Southampton Island, Baffin Island, and the McConnell River. Wrangel Island in the USSR is also a protected area. Many snow geese also winter in wildlife sanctuaries, predominantly in the United States. However, there is one important protected wintering area in Canada. The Lesser Snow Geese from Wrangel Island are one of the most important winter users of the Alaksen National Wildlife Area, on the Fraser River delta. There, a major wildlife spectacle is repeated annually as thousands of Snow Geese return to a traditional habitat, right beside the city of Vancouver.

Reading list

• Bellrose, F.C. 1981. Ducks, geese and swans of North America. Rev. ed. Stackpole Books, Harrisburg, Pennsylvannia.
• Godfrey, W.E. 1986. Birds of Canada. Rev. ed National Museums of Canada, Ottawa.
• Johnsgard, P.A. 1974. Song of the north wind. Anchor Press/Doubleday, Garden City, New York.
• Palmer, R.S. 1976. Handbook of North American birds. Vol. 2, Waterfowl (part I). Yale University Press, New Haven and London.

	Canadian Wildlife Service - Hinterland Who's Who series Reproduced with permission of the Minister of Public Works and Government Services Canada, 1999. Copyright © 1999 Environment Canada. All rights reserved. Last update: 19 January 1999