WILDLIFE
BIOLOGUE

TRUMPETER
SWAN

(Olor buccinator)

‘orth America is home to three
Ne of swans: the native

trumpeter and tundra (formerly
known as whistling swan), and the non-
native mute. The trumpeter swan is the
largest waterfowl in North America and
the largest swan in the world.

The trumpeter swan’s historic breed-
ing range extended in a wide band from
the Bering Sea east through almost all
of Canada and south to Missouri,
Illinois, and Indiana.

Today, the central Alaska population
winters from southeastern Alaska along
coastal British Columbia south to the
mouth of the Columbia River on the
southern border of Washington State.
Other trumpeters are found in mixed
migratory/non-migratory groups across
the Great Basin region of Alberta,
Washington, Oregon, Nevada,
Montana, Wyoming, South Dakota,
and Minnesota. State fish and wildlife
agencies are currently undertaking
recovery efforts to reestablish popula-
tions in Michigan, Minnesota, and
Wisconsin.

The trumpeter swan is a majestic
bird, with snowy white feathers; jet-
black bill, feet, and legs; and 8-foot
wingspan. At close range, a thin
orange-red line can be seen on the
lower part of the
bill. The trum-
peter is often
confused with
the smaller, more
northerly tundra
swan,

especially where their ranges overlap.
The major differences between the
two are their size, call, and migration.
The trumpeter swan is roughly twice
the size of the tundra swan; has a
deep, sonorous call; and is either non-
migratory or migrates relatively short
distances. The tundra swan weighs
approximately 15 pounds, has a high
whistling call, and migrates long dis-
tances between summer and winter
ranges.

Trumpeter swan habitat includes
riverine wetlands (wetland areas associ-
ated with rivers); lakes, ponds, and
marshes; open wooded regions; and
prairies. In winter, they can be found on
tidal estuaries.

Trumpeter swans establish life-long
mates at approximately 3 years of age
and nest the following year. Sometime
between late March and early May, they
build their nests, choosing locations
close to the water, either on shore, small
islands, or muskrat and beaver lodges.
The male (called a cob) gathers nest
material, uprooting marsh plants such
as cattails, sedges, bulrushes, and horse-
tail, and brings them.

to the female (called
a pen) for place-
ment. The nest
mound, which takes
about 2 weeks to
build, reaches a
diameter of 6 to 12

feet and an average height of 18 inches.
The same nest site may be used for sev-
eral years. Once the nest is complete,
the pen lays one egg every other day
until she has a full clutch, usually from
3 to 9 eggs. The pen spends an average
of 35 days incubating the eggs while the
cob stays nearby to defend the nest
against intruders or predators. When
they hatch, the downy young (called
cygnets) are grayish with pink bills and
weigh about 1/2 pound each. Although
able to swim immediately, they usually
stay in the nest for at least another 24
hours.

Newly hatched cygnets feed mainly
on aquatic insects and crustaceans. At
about 5 weeks of age, their diet changes
to include more vegetation. By the age
of 2 to 3 months, the cygnets’ diet is
basically the same as that of the adults.
The tubers of duck potato and sago
pondweed are important foods for trum-
peter swans. They also feed on the
stems, leaves, and seeds of other aquatic
plants. Trumpeter swans use their
strong webbed feet to dig into the pond
or lake bottom for roots, shoots, and
tubers, then plunge their heads and
necks underwater to eat what they've
dug up. In deeper water, they tip up
completely to snap off the leaves and
stems of plants growing underwater.

Their heads and necks are often
stained a rusty color from
feeding in ferrous (contain-
aN ing iron) waters.
"Trumpeter swans grow
rapidly. By 8 to 10 weeks of age, young
trumpeters have reached half their

The largest of North American waterfowl, the trum-
peter swan has snowy white feathers; a jet-black
bill, feet, and legs; and an 8-foot wingspan.


adult size and are fully feathered. They
retain their gray juvenile plumage until
the second winter.

Average age at first flight is 14 to 17
weeks in Alaska and 13 to 15 weeks in
other areas of their range (some of the
cygnets may not survive to flight stage).
Trumpeter swans fly with their
long necks and legs fully
extended, rather than
tucked. They swim
with their necks
erect, in contrast to mute swans,
which swim with their necks in an
“S” curve.

The trumpeter swan is vulnerable to
illegal shooting, collisions with power
lines, and predators such as snapping
turtles, great horned owls, raccoons,
and minks which steal the eggs and
attack the young.

Studies have also shown that trum-
peter swans may develop lead poisoning
by ingesting lead shot and fishing
sinkers during feeding. A relatively
recent ban on lead shot for waterfowl
hunting has helped significantly
decrease this threat in that no new
pellets are being deposited in the envi-
ronment, but old pellets may remain
in the sediment of lakes and wetlands
for several decades.

Under the Migratory SS
Bird Treaty Act, carefully 28
managed hunting of some
migratory birds is allowed
under regulations developed
each year by the U.S. Fish
and Wildlife Service. The
trumpeter swan’s close
resemblance to the tundra
swan and the snow goose, which

‘\ are both legal game in some areas,
4 makes it vulnerable to a certain
amount of hunting pressure due
to mistaken identity.

Widespread destruction and
degradation of wetland areas also
decreases the suitable habitat areas for
the trumpeter swan.

In the early 1900s, the trumpeter was
hunted nearly to extinction for its skin,
feathers, meat, and eggs. Passage of the
Migratory Bird Treaty Act of 1918 gave
protection to trumpeter swans and
other birds and helped curb illegal
killing,

In 1932, fewer than 70 trumpeters
were known to exist worldwide, at a
location near Yellowstone National
Park. This led to the establishment of
Red Rock Lakes National Wildlife
Refuge in 1935. Red Rock Lakes is
located in Montana’s Centennial Valley

yore:

Both the male, called a cob, and female, called a pen, build the nest and help raise the young. Called
cygnets, young trumpeters are grayish with pink bills and weigh about 1/2 pound each. By 8 to 10 weeks,
they have reached half their adult size and are fully feathered,

Trumpeters fly with their long necks
and legs fully extended, rather
than tucked.

and is part of the Greater Yellowstone
ecosystem. Nearly half of the known
trumpeter swans in 1932 were found

in this area. The area’s system of hot
springs provides year-round open waters
where trumpeters, as well as other
wildlife, find food and cover even in

the coldest weather.

Over the years, the Red Rock Lakes
refuge flock served as an important
source of breeding birds for reintroduc-
tion efforts in other parts of the country,
primarily on other national wildlife
tefuges in the Midwest.

In the early 1950s, a fairly large,
previously unknown population of
trumpeter swans was discovered in
Alaska. Today, estimates show about
16,000 trumpeter swans reside in North
America, including some 13,000 in
Alaska, which winter on the Pacific
Coast; more than 1,600 in Canada;
about 500 in the Midwest; and more
than 500 in the tri-state area of Idaho,
Wyoming, and Montana (including the
Red Rock Lakes refuge flock).

BIOLOGUE SERIES

Prepared by:

U.S. Department of the Interior
U.S. Fish and Wildlife Service
1995