Oceanography | Vol.31, No.1
RIPPLE MARKS: THE STORY BEHIND THE STORY
Icon of Chesapeake Winter
Still Graces the Bay
“They came back. This winter.” Biologist Donald Webster’s voice has a wistful note, won-
dering if the king of ducks, as the beautiful, crimson-headed canvasback is known, will
return to rule Chesapeake Bay in future seasons.
Bundled in parka, gloves, and hat, Webster, waterfowl coordinator for the Maryland
Department of Natural Resources, raises his binoculars near a seawall at the confluence
of the Chesapeake and the Choptank River in Cambridge, Maryland. The overlook is
a mecca for wintering canvasbacks and other ducks. Chesapeake Bay is the largest
estuary in the United States and one of the most productive water bodies in the world,
attracting myriad waterfowl species.
“Canvasbacks, the ducks everyone comes to see, are usually here in force by
Christmas, sometimes by Thanksgiving,” Webster says. “They stay through early to mid-
March, then they’re gone, heading north to nesting grounds.”
Chesapeake skies fill with migrating
ducks—canvasbacks, buffleheads, greater
and lesser scaup, and many others—from
December through March. The bay is the
Atlantic Coast’s most important water-
fowl migration and wintering area. The
Chesapeake and its 19 major tributaries
offer refuge to 24 species of ducks as well
as Canada geese, greater snow geese,
and tundra swans.
“Long-term worsening of the bay’s
water quality, however, and loss of habitat,
especially the grasses so many of these
birds depend upon, have contributed to
declines in wintering waterfowl popula-
tions,” says Webster.
SEESAWING GRASS ESTIMATES
An estimated 97,433 acres (400 km2)
of submerged aquatic vegetation (SAV)
remained in the bay and its tributaries in
2016, down from historic levels that may
have reached more than 600,000 acres
(2,500 km2).
There’s good news, however, in the
2016 estimate. It’s an 8% increase over
2015, and more than twice the SAV in the
bay in 2013.
In 2011, the Chesapeake’s SAV declined
to 48,195 acres (195 km2), a result of the
effects of Hurricane Irene and Tropical
Storm Lee. The storms sent a flood of
sediment cascading down rivers and into
the bay. After 2011, conditions became
relatively dry, reducing the flow of
grass-smothering sand and mud. More
sunlight reached submerged grasses,
allowing them to rebound. In return,
the SAV filtered runoff, helping keep
Chesapeake waters clear.
Forty years ago, SAV reached what
may be its lowest point in parts of the
bay. Another major storm, Tropical Storm
Agnes in 1972, nearly wiped out the SAV
at Susquehanna Flats, an expansive bed
of grasses where the Susquehanna River
Oceanography | Vol.31, No.1
BY CHERYL LYN DYBAS
PHOTOS BY ILYA RASKIN
SKEINS OF WATERFOWL
On this late January morning with calm
winds and temperatures that hover just
above freezing, the canvasbacks’ red
heads stand out in quiet, winter-dark
waters. The ducks glide near the sea-
wall, where a dozen photographers jostle
for the quintessential shot of an iconic
Chesapeake species. “This place is known
as the ‘wall of shame,’” laughs Webster,
“because it’s almost too easy to get great
canvasback pictures here.”
After the warm winter of 2015–2016
and its low numbers of canvasbacks,
they’ve arrived in large flocks this season
(2016–2017).