U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2004-3118

October 2004

Upper Midwest Environmental Sciences Center, La Crosse, Wisconsin

Tundra Swans on the Upper Mississippi River

Breeding grounds

Migration route

Wintering grounds

Range of the Eastern Population of tundra swans. This map is an interpretation of an electronic 

version derived from various sources.

Tundra swans in Upper Mississippi River backwaters

Tundra swan viewing 

has become an 

increasingly popular 

fall recreational 

activity on the Upper 

Mississippi River. 

As fall foliage peaks in color on the 

bluffs along the Upper Mississippi River 

(UMR), the high-pitched bugling calls 

of thousands of tundra swans resonate 

from the once-quiet backwaters of the 

river. An abundant food supply and 

relatively undisturbed resting sites make 

the UMR an important staging area for 

tundra swans (Cygnus columbianus 

columbianus) during fall migration. Prior 

to the 1970s, only “small numbers” of 

tundra swans consistently stopped along 

the Mississippi River on their way to 

wintering grounds in the Chesapeake 

Bay. In recent years, fall swan numbers 

on the UMR have swelled to more than 

30,000 during late November. 

Tundra swans are the most common and 

widespread species of swans in North 

America and are divided into two distinct 

populations: the Eastern and the Western 

Population. Birds migrating through 

the UMR are the Eastern Population of 

tundra swans. These birds breed along 

the arctic coast 

of Canada from 

Hudson Bay west 

to northwestern 

Alaska. Today the 

Eastern Population 

of tundra swans 

numbers around 

100,000. The 

Eastern Population 

of tundra swans 

migrate south 

through the 

prairie provinces 

of Canada, the 

Dakotas, and 

Minnesota to reach the UMR by mid to 

late October. The last swans depart the 

UMR with freeze-up, usually in mid to 

late December. Scientists estimate that 

about 25% of the Eastern Population of 

tundra swans, including about half of all 

young produced, use the UMR during fall 

migration.

On the arctic breeding grounds, swans 

begin nesting as early as spring thaws 

permit because their young need about 

60 to 70 days to develop after hatching. 

Tundra swans first breed when they are 

2 to 3 years old and breeding pairs mate 

for life. Female tundra swans prefer 

to nest on shores, points, islands, or 

vegetated hummocks of lakes, ponds, or 

marshes. The females lay an average of 

six eggs over 6 to10 days. The young, 

called cygnets, hatch after 31 to 32 days 

of incubation. Cygnets are brownish-
Female tundra swan on nest in Arctic breeding grounds

For more information, contact

Kevin Kenow

USGS Upper Midwest Environmental Sciences Center

2630 Fanta Reed Road

La Crosse, WI 54603

Phone: 608.781.6278

Fax: 608.783.6066

kkenow@usgs.gov

http://www.umesc.usgs.gov/

gray for their first 6 to 8 months, whereas 

the plumage of adult tundra swans is 

completely white. A small yellow spot 

is often visible at the base of the adult’s 

black bill. Tundra swans weigh between 

13 to 20 pounds, average about 3 feet in 

height and have a wingspan of 6 to 7 feet. 

Family groups, consisting of white adults 

and gray cygnets, can easily be identified 

on the UMR. By the time the birds reach 

the UMR, the average number of young 

per family is about two. 

Along the UMR, tundra swans feed 

primarily on the leaves, stems, and 

tubers of aquatic plants. Arrowhead, 

sago pondweed, and wildcelery grow 

in abundance in shallow marshes and 

impounded areas and are important 

foods for tundra swans on the UMR. An 

adult swan consumes an estimated 6.2 

pounds of tubers per day on the UMR. 

Tundra swan viewing has become an 

increasingly popular fall recreational 

activity on the UMR. The best time to 

view tundra swans is from mid-October 

through mid-November. Popular viewing 

areas include the Watchable Wildlife 

Observation Platform at Rieck’s Lake 

Park near Alma, Wisconsin, and along 

Highway 26 south of Brownsville, 

Minnesota.

Scientists from the Upper Midwest 

Environmental Sciences Center, in 

collaboration with the U. S. Fish and 

Wildlife Service, are studying the ecology 

of tundra swans during fall migration. 

We are using digital aerial photography 

to determine the daytime distribution and 

abundance of swans on the UMR and 

thermal infrared imaging to document 

their nighttime location. We will relate 

swan locations to the availability and 

distribution of food resources within 

selected areas of the UMR. We are also 

interested in how swans might affect the 

availability of arrowhead, wildcelery, 

and sago pondweed for other birds. 

River managers and biologists will use 

this information to develop management 

strategies that enhance the UMR as an 

important stopover area for swans.

Photo by Victor Fazio III and used with permission