Status: Abundant Native Migrant

(Chen caerulescens caerulescens)


Lesser snow geese, which fly through South Dakota, are the smaller of two subspecies of snow geese, the larger subspecies
being found on the east coast of the United States. The genus name, Chen, is Greek for goose and the species name is Latin
for bluish. Lesser snow geese can be one of two colors, white (snow) or gray/blue (blue), thus their common names, "snows
and blues." It was once thought that these two colors of geese were separate species. Since they interbreed and are found
together throughout their ranges, they are now considered two color phases of the same species. These colors are genetically
controlled with the dark phase resulting from a single dominant gene and the white phase being homozygous recessive .
When mating the young will select a mate resembling their parents. If they were reared by a mixed pair, they will mate with either color phase.


They stand 25 to 31 inches (63.5-78.7 cm) tall and weigh 4.5 to 6.5 pounds (2-3 kg). The adult snow phase is all white with
black wing tips. The immature snow phase also has black wing tips, but all other feathers are sooty or dirty white. The adult
blue phase has a gray/blue body, black wing tips, a white neck and head, and varying amounts of white on their bellies. 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 a black "grin patch." The colors are not as bright on the feet, legs, and bill of
immature birds.

Lesser snow geese are found throughout South Dakota during their spring and fall migrations. They are more common east
of the Missouri River. Snow geese often concentrate on or near Sand Lake National Wildlife Refuge in Brown County and in
Brookings, Kingsbury, and Lake counties. In any given year, large concentrations may be in other areas of eastern South
Dakota as well. 

Natural History

Snow geese migrate through South Dakota between early March and early April in the spring and mid-October and
mid-November in the fall. They migrate in flocks of 100 to 1,000 or more. During migration, they often fly at altitudes of
2,000 to 5,000 feet (308-1538 m) and occasionally as high as 10,000 feet (3,077 m) or more. In late April of 1991, an
estimated 1.2 million snow geese were in the Sand Lake National Wildlife Refuge area at one time. At that time, this total
was 60% of the mid-continental snow goose population. In 1996, the mid-continental population was estimated at just under
3 million birds.

Snow geese travel through South Dakota to and from their wintering grounds on the Gulf Coast and their breeding grounds on
the Arctic tundra of Canada. Major breeding concentrations are along the Hudson Bay and on Baffin Island. Snow geese nest
in large colonies with as many as 1,200 nests per square mile. There are as many as 500,000 snow geese in some of these
colonies. Snow geese nest in June and July, laying 3 to 8 white eggs per nest. The females incubate the eggs for 23 to 25
days while the males stand guard. The goslings can fly 38 to 49 days after hatching. The number of young produced in any
given year depends largely on how early the tundra surface begins to melt, vegetation begins to grow, and the adults can
begin to nest. The birds leave the tundra to begin their fall migration in early to mid-September.

On the tundra, snow geese eat grasses, marsh vegetation, and other plants. Traditionally, snow geese eat marsh and upland
vegetation during their migration. They have adapted to changes caused by human development and now feed primarily on
agricultural crops during their migration.

Conservation Measures

During the 1990's, the mid-continental snow goose population has been increasing. They are nesting in such high
concentrations that they are stripping the tundra of the very vegetation that they need to survive. It is feared that their
population may crash from disease and/or the damage they are causing to the Arctic tundra. Federal, state and private
agencies are keeping a close watch on the health of these populations. Licensed hunters are allowed to shoot a specified
limit of geese during designated times of the year. The money derived from license fees and taxes paid by the hunters is used
to care for and protect wildlife populations. Limits have been increased to allow hunters to harvest more snow geese to
hopefully prevent an uncontrolled population crash. However, it is uncertain if hunters can sufficiently decrease the


Clutch - the number of eggs laid in a nest at one time.

Goslings - young geese.

Homozygous recessive - having two identical forms of the gene for a characteristic, both of which are recessive, i.e., ones that would not be expressed if a dominant form were present.

Incubate - to keep eggs in a favorable environment for hatching which is accomplished by the female sitting on the eggs in the nest.


Bellrose, Frank C., 1976, Ducks, Geese, & Swans of North America, A Wildlife Management Institute Book; Stackpole
Books: Harrisburg, Pennsylvania, 17105.
SDOU, 1991, The Birds of South Dakota, NSU Press: Aberdeen, SD 57401.
Terres, John K., 1980. The Audubon Society Encyclopedia of North American Birds, Alfred A. Knopf, New York.

Written by:
Todd Frerichs, U.S. Fish and Wildlife Service, Sand Lake National Wildlife Refuge, Columbia, SD 57433. 1997.

Reviewed by:
Dr. Dan Tallman, Biology Professor, Northern State University, Aberdeen, SD.

Publication of the Lesser Snow Goose fact sheet was funded by the South Dakota Department of Game, Fish and Parks,
Division of Wildlife, Pierre, SD.