The annual sighting of returning ospreys in the Chesapeake Bay region marks the beginning of spring. After migrating up to 2,000
miles from the coasts of South and Central
America, Cuba, and other Caribbean islands,
ospreys come home to breed on the shores
of the Chesapeake. Upon their return, these
charismatic “fish-hawks” quickly get to work
constructing nests on power poles, navigation
aids, constructed platforms, and duck hunting blinds. Ospreys are highly adaptable, and
nests can be found in some of the most urbanized and industrialized areas in the region.
Ospreys tend to forage for fish fairly close to
their nesting sites, and as a result, osprey eggs
and young have been shown to be excellent
indicators of local water quality. This is one
reason why ecotoxicologists have used them
as a sentinel for environmental contaminants.
From 2000 to 2001, the U.S. Geological Survey
(USGS) and U.S. Fish and Wildlife Service
(USF WS) used ospreys to conduct a large-scale
contaminant study in the Chesapeake Bay.
The research focused on “regions of concern”
including Baltimore Harbor and the Patapsco
Anacostia and mid-
dle Potomac Rivers bor-
dering Washington, D.C.; and the Elizabeth
River in Virginia. Scientists found that con-
centrations of pesticides, like DDT, in osprey
eggs were lower than historic values, but levels
of PCBs (banned since the 1980s) had not
declined. A few eggs contained concentra-
tions of flame retardant chemicals that were
approaching levels of concern.
Approximately 10 years later, my dissertation
research, conducted in collaboration with
USGS and USFWS scientists, has taken
another look at contaminants in Chesapeake
Bay ospreys. Our results document the con-
tinued recovery of the osprey population and
declining levels of many now-banned con-
taminants in eggs. Not unexpectedly, we also
found the vast majority of nests contained
trash—plastic materials, fishing tackle, cord-
age, fabric, etc. In 2011, all 25 nests surveyed
in Maryland contained a variety of trash
materials and 15 of 19 nests surveyed on the
rivers surrounding Washington, D.C., con-
tained trash. Even nests in remote mid-Bay
islands contained trash, fabrics, and cordage
materials. Adults and chicks may become
entangled in debris like fishing tackle, six-
pack rings, and plastic bags. If ingested, these
materials constitute a choking hazard and are
known to cause internal harm. Occasionally,
we have found a nestling impaled by a fishing
hook. It is unclear if the birds are using these
man-made materials as decorations, or have a
limited source of nest construction materials.
Interestingly this behavior has been docu-
mented worldwide with species of raptors
including bald and golden eagles, saker fal-
cons, and upland buzzards. Nonetheless, the
presence of these materials in osprey nests is
concerning and a visible reminder of the
unfortunate effects we have on the Bay’s nat-
It is unclear whether birds use debris as
decoration or for nesting materials, but the
behavior has been documented worldwide.
While working on her Ph.D. dissertation on
contaminants in Bay ospreys, Dr. Rebecca Lazarus
examined over 60 osprey nests.
By Dr. Rebecca Lazarus
CBF’s New Osprey Cam!
CBF now has an osprey platform and
webcam overlooking our Merrill Center
headquarters and the beautiful Bay.
As of May 2 \ , we have a nesting pair
and three eggs. Check on their progress
but remember that this is no Disney
film! Nature can be a cruel place, but
it is our policy not to interfere with
anything that goes on in the nest.
We also will use our discretion to
turn off the camera at any time. Visit
Dr. Rebecca Lazarus completed
her Ph.D. at the University of
Maryland in December 2015.
CBF scientist Dr. Beth McGee
was on her thesis committee.