The epic journeys of tundra swans to the
Chesapeake’s fields and marshes are like
winter vacations to a tropical getaway. In
this farm field south of Cambridge,
Maryland, they peck at soybeans frozen in
the mud, rebuilding their strength after
problems, Hindman said. As a result, more
swans are feeding in farm fields. Others are
skipping the Chesapeake region altogether
and flying farther south.
“The birds are spending more time in
North Carolina,” Hindman said.
Tundra swans used to be called whistling
swans. But they don’t really whistle—just as
their better-known cousins, mute swans,
are not really mute. Mute swans, the fairy-tale-looking swans with orange knobby
bills and curved necks, are from Europe.
They are an invasive species here,
unwanted by wildlife managers
and many other people, because
mute swans rip up underwater
grasses and aggressively drive away
native species, such as least terns
and black skimmers.
From 1971 to 1975, aerial surveys estimated
an average of 39,100 tundra swans a year
wintering in Maryland and Virginia. But
then there was a major drop, starting in the
1980s. From 2006 to 2010, an average of
only 17,000 tundra swans—less than half as
flushed into the Bay by Hurricane Agnes in
1972. Since then, there have been rebounds
of the grasses in some areas, including the
northern Bay around the Susquehanna Flats.
But overall, by 2011, the amount of aquatic
vegetation in the Bay remained at less than
10 percent of historic levels, with only
57,964 acres of grasses, according to the
Virginia Institute of Marine Science.
The migration of tundra swans is
one of the most distinctive and
beautiful phenomena to grace the
“That could be the most logical explana-
tion,” for the decline in the number of tun-
dra swans wintering in the Bay, said Robert
By contrast, the more slender and
straight-necked tundra swans are
the old aristocracy here in the Chesapeake
region, too refined to grunt, hiss, or brawl.
Tundra swans entertain each other by form-
ing clarinet ensembles—choruses of reedy,
“Their call is an incredible sound, and you
should not take it for granted,” said Larry
Hindman, Waterfowl Program Manager for
the Maryland Department of Natural
Resources. “For some people, to see and
listen to these birds, it is a once-in-a-life-
many as in the early 1970s—wintered in
these two states, according to survey figures.
Meanwhile, the total number of tundra
swans in Eastern North America grew by 43
percent over this time period. Additionally,
the number wintering in North Carolina
more than tripled, from an average of
20,700 from 1971 to 1975 to 68,600 from
2006 to 2010, according to survey data.
Clearly, the birds are finding the
Chesapeake less desirable, Hindman said.
Compounding the problem is the
fact that another food of the tundra
swans, softshell clams, has suffered
a near disappearance from the Chesapeake
Bay. Softshell clams were once as common
as grass on the Bay bottom. But commercial
harvests of softshell clams with machines
called hydraulic escalator dredges began in
the 1950s. Harvests plummeted from an
average of 500,000 bushels a year from
1956 to 1971, to 2,665 bushels in 2010,
according to the Maryland Department of
Natural Resources. The cause for the
decline remains unclear, but could include
a protozoan parasite, a viral disease, and
As he speaks, the tundra swans in this field
take flight. Their wing strokes are knifelike, graceful and powerful, as they soar up
and over the row of trees edging the field.
Their fantastically white feathers flash in
dazzling contrast to the brown woods, iron
fields, and dead grasses.
Hindman’s job is to watch the arrival of
tundra swans every winter and estimate
their numbers. Over 35 years of spying on
their flocks from low-flying airplanes,
Hindman knows tundra swans are a less
frequent sight here.
While numbers of tundra swans appear to
be healthy across the continent, fewer and
fewer are wintering in the Chesapeake Bay.
This may be in part because the underwa-
ter grasses and soft clams they normally eat
are being killed by pollution and other
“The real threat to tundra swan habitat in the
Chesapeake Bay region is too many people
and urbanization, and what they do to the
quality of the water,” Hindman said. “You’ve
got to have good water quality to produce
submerged aquatic vegetation, and of course
that is one of the problems with the grasses
in the Chesapeake Bay. We have too many
pollutants and high levels of nutrients that
are damaging to the Bay grasses.”
At its most pristine, the Chesapeake Bay
supported more than 600,000 acres of sub-
merged aquatic vegetation, according to the
Virginia Institute of Marine Science. These
grasses not only provide food for birds and
habitat for blue crabs and many other aquat-
ic species, but also help filter and clean the
water. Water pollution and sedimentation in
the Bay caused a major decline in these
underwater grasses starting in the 1950s,
with a major blow to grasses dealt by runoff
“Softshell clams have been characterized by
some as a keystone species in the Bay,” said
Chris Dungan, Manager of Shellfish Health
at the state agency. “But they were much
more of a keystone in the 1950s than today.
Today there are not as many left.”
Remove keystones, and the building falls.
The migration of the tundra swans is one of
the most distinctive and beautiful phenomena to grace the Chesapeake’s winters. But
unless we do more to restore the Bay’s
ecosystem, the songs of these arctic angels
may become just a memory.
Tom Pelton, an award-winning
environmental journalist, is
Senior Writer and Investigative
Reporter for CBF. Read his blog