Conowingo Dam is located
in northeastern Maryland on the Susquehanna River just northwest
of where the river empties into the northern part of the Chesapeake
Bay. It is about eight miles above the town of Havre de Grace. If
you are looking at a road map, Havre de Grace is where Interstate
95 crosses the Susquehanna. The precise location of the dam is where
Route 1 crosses the river. Route 1 crosses the river on top of the
dam. Access to the base of the dam, and to gull and other birdwatching,
is from Route 1. Just south of the river, turn east on Shuresville
Road. After one-half mile, make the first left, onto Shures Landing
Road. Follow the road to the parking lot at the base of the dam,
where it dead ends. Most observation is done from the area closest
to the dam at the far end of the parking lot. There is a pavilion
there which provides shelter during bad weather. The parking lot
is open every day of the year from at least 6:00 a.m. until 10:00
p.m. Shuresville Landing Road is steep and winding and may not be
passable immediately after snowstorms but it is quickly cleared
because it is the access road for workers at the dam. There are
public bathrooms at the pavilion. Just north of the dam, on Route
1, at the junction of Route 222, there is a store that has gas,
coffee, and sandwiches. At the same intersection there is a small
diner that provides cheap food. It is warm.
( Click on the map to browse )
primary attractions at the dam are gulls and Bald Eagles. Conowingo
is an electricity generation plant. When the turbines are running,
large intake valves suck water, and fish, through the dam, providing
excellent feeding for piscivorous birds. The generation schedule
is erratic because the dam is a secondary facility and only generates
when demand is high. There is some generation almost every day,
but on some days it is only early in the morning and late in the
day. There is a fisherman's catwalk across the front of the dam
which is accessible to birdwatchers most days and provides close
looks at the feeding birds. On the far side of the dam, where there
is no access, there are a large number of rocks where birds loaf.
It requires a scope to see those birds well. Birds feeding at the
base of the dam during generation are in the air most of the time
and are close enough to be viewed with binoculars.
Large numbers of gulls and
Bald Eagles are typically present from mid-October through mid-March.
The highest numbers of gulls are present from December through February.
Some gulls and Bald Eagles are present in all seasons. Also present
all year are large numbers of Great Blue Herons, and there is an
active heronry in the woods across from the parking lot. The nests
are visible from the viewing area and breeding activity can be watched
throughout the spring and summer. A few pairs of Black-crowned Night-Herons
have bred on the large island immediately below the dam in recent
years and they are present year-round. In non-breeding season they
tend to congregate during the day in the brush and small trees at
the south end of the island. Careful searching with a telescope
usually results in the discovery of at least some of the birds.
Small numbers of other herons are present spring through fall. Terns
are occasionally numerous in spring and fall. Waterfowl, especially
Common Mergansers, are fairly numerous in winter. Ospreys attempt
to nest on the large transmission towers on the island below the
dam. Bald Eagles have attempted to nest on the transmission towers
on the other side of the river the past several years.
Bald Eagle numbers vary from
a half-dozen in summer to 30-40 in winter. It is not unusual to
find 20 in a single scan from November through February. While there
are larger concentrations elsewhere, Conowingo is considered one
of the best places east of the Mississippi River to view Bald Eagles
because the birds are nearly always present in good numbers and
viewing conditions are excellent. The sun is nearly behind observers
all day throughout the year. About one out of three winters a single
Golden Eagle is found with the Bald Eagles.
Gulls: The reason most bird watchers go to Conowingo.
Numbers begin to build in November with the influx of Ring-billed
Gulls. Numbers in some years reach 20,000 by the end of the month.
Until January, Ring-billeds typically outnumber Herring Gulls 5-10
to one. Following the advent of colder weather in most years, the
ratio changes to one-to-one and in some years the preponderance
of birds are Herring Gulls by mid-winter. The pattern is largely
dependent on how cold a year it is and how much open water is available
to the north of Conowingo. Gull numbers begin to diminish in early
March. Between 100-500 Great Black-backed Gulls are present throughout
the period. The numbers of Bonaparte's Gulls is highly irregular
in fall. In some years numbers in November and December reach 2500,
but in many years no more than 100-200 are found.
Rarer gulls: The large concentration has resulted
in many rarer species being found.
Lesser Black-backed Gull: Perhaps should be included in the regular
list above. They have been found every year (persistent observations
at the dam go back more than 14 years) and single-day counts have
varied between 1-17. Lesser Black-backed is missed on fewer than
five percent of the days between November and February. All ages
are seen annually and first-winter birds are fairly frequent. There
is a retaining wall in the center of the dam and an adult has been
seen sitting on the wall almost every day in winter for at least
Iceland Gull: Present almost every winter. The
high count is 11. Typically 1-4 are found. Most are first-winter
birds but every age has been seen.
Glaucous Gull: Present most winters but less numerous
and consistent than Iceland. Typically 1-2 are found and the high
count is about 5. Almost all are first-winter.
Thayer's Gull: Present in at least half the years.
Most years only one is found but the seasonal high is three. Most
are first-winter or adult.
Slaty-backed Gull: A gull thought to be a Slaty-backed was seen
by several hundred observers over a two-week period in the winter
of 1998-99. Uncertainty exists about the range of variation in the
species and although photographs and field notes seem to support
the identification in many observers eyes, others retain some reservation.
It is difficult to absolutely rule out hybrid origin on the basis
of the available evidence.
California Gull: Found three times in winter. Probably
overlooked because close observation of sitting birds is more difficult.
Common Gull: A single first-winter bird of the
European race was reported by multiple observers several winters
ago. A second report of a first winter bird, seen and photographed
by dozens of people and widely circulated as a Common Gull, is now
thought to be a slightly aberrant Ring-billed Gull. Controversy
over the identification of the species in first-winter plumage has
created uncertainty about the status of the species.
Common Black-headed Gull: Reported about six times.
Records span the winter season.
Little Gull: Found twice, both adults with large
flocks of Bonaparte's Gulls late in the fall.
Franklin's Gull: Two late fall records, both adults.
Laughing Gull: Scarce but regular in late summer
and early winter.
Black-legged Kittiwake: Two records. First-winter birds
were found in December and January of 1997 and 1998.
Photo by Les Eastman
Caution: Occurrence of large numbers of birds depends
on the availability of fish, primarily gizzard shad. Several years
ago a spring flood wiped out the gizzard shad breeding effort and
numbers were quite low the following winter, and the high count
of gulls was less than 2,000. In good years, with normal fish numbers
and cold weather, 25,000+ birds can be found at the base of the
dam most days. During the times when there is no generation the
birds disperse down river and onto the lake above the dam, to which
there is limited access. During the slow period, no more than 5,000
gulls may be present for close observation. In the winter of 1995/96
25,000 gulls were present until a sudden thaw in late January resulted
in a tremendous volume of water coming down the river. The floodgates
at the dam were opened for several days and there was downstream
flooding. Following that event there were virtually no gulls at
the dam for the rest of the season. No similar circumstance has
occurred in the twelve years of observation.
When there is no generation
and gulls are not feeding below the dam, the birds tend to gather
in flocks on the rocks directly across from the pavilion, on the
rock bars and small islands down river, and on the river (also referred
to as the pond and the lake, although it is part of the Susquehanna
River) above the dam. It is often possible to observe thousands
of gulls from the south end of the parking lot or by walking the
trail downriver and scoping from various vantage points. Almost
all of the rarer gulls have been seen down river at times, and Franklin's
Gulls have only been seen from the south end of the parking lot
and from farther down river.
Above the dam.
It has long been a source
of frustration that viewing birds above the dam is difficult. The
access is limited, but persistent efforts have revealed that large
numbers of birds are present fall through spring and that some species
considered rare in Harford County are nearly regular there. The
Susquehanna River is a major migratory pathway for waterbirds and
many stop in the deeper water above the dam but are rarely found
on the river below the dam. Locally rare species that have been
found above the dam include all three species of scoters, Oldsquaw,
Red-throated Loon, Brant, Eared Grebe, Great Cormorant, Parasitic
Jaeger, and Pacific Loon. This list is certainly not indicative
of the full potential because coverage has been sporadic. Very large
concentrations of ducks have been found fall through spring. Common
Mergansers can be abundant, when water to the north is frozen, and
high counts approach 20,000. Large numbers of Bufflehead, Common
Goldeneyes, scaup, and some puddle ducks are also regular.
It is typical for large numbers
of gulls to roost directly above the dam when they are not feeding
in the tailrace during generation. In addition, thousands of gulls,
especially Bonaparte's in season, and Ring-billeds, feed on the
river. Large numbers of terns also feed above the dam in spring
and fall. Iceland, Glaucous, Thayer's, and Lesser Black-backed have
been seen above the dam, and Common Black-headed has been seen on
several occasions feeding with the Bonaparte's.
Access is a significant problem.
On the Harford County side of the river, which is the same side
as the parking lot at the dam, there are two spots. The first is
close to the dam and viewing conditions are somewhat limited. The
access is from the extreme left-hand end of the parking lot at the
visitor's center on the north side of Rt. 1, about 100 yards south
of Shuresville Road. Enter the parking lot and stay to the left
and proceed to the bottom of the lot, next to the small maintenance
shed. From the corner of the parking lot you will find a trail down
the hill through the woods. It is about 75 yards to the edge of
the river and a small promontory. From this spot it is possible
to scope up and down the river and the light is always good.
The second spot requires
some walking. From the visitor's center parking lot, go south on
Rt. 1 (away from the dam) for about one half mile until you see
a yellow gate on your right near the top of the next hill. Park
on the side of the road. (DO NOT BLOCK THE GATE!) Walk around the
gate and follow the access road for about one half mile. The access
road goes to a large warning sign for boaters. In front of the sign,
there is an extensive view up river and the light is always good.
The best access to the river
is from the Cecil County side of the river. Cross the dam on Rt.
1 and go to the top of the hill and the traffic light at Rt. 222.
Turn left and go about 1 mile to a left turn (the first left) at
Mt. Zoar Road. Follow the road to the small boat launch. The boat
launch is in the mouth of the creek and access to the river here
is poor, requiring clambering over rocks to get to the railroad
tracks. Drive past the boat launch and cross the old metal bridge.
The road immediately turns back to the river. After one-half mile
you will see a pull over on the left, with room for two or three
cars. The pullover is the entrance to the old access road to the
railroad tracks but is now blocked by a concrete barrier. Walk around
the barrier and down to the railroad tracks, about 100 feet.
(** This note added January 2009 **) The section of Bell Manor Road
that leads to the overlook is closed and my never be reopened. It
is closed from the boat ramp at the end of Mt. Zoar Road to just
below the entrance to the Girl Scout Camp, blocked off with concrete
jersey barriers. It is possible to park the car at either end and
walk to the overlook. However, it's not exactly a safe area to go
walking around in, and it is not recommended that people park and
walk unless they are in groups.
The railroad tracks run along
the river for the entire Maryland portion, providing excellent views.
The disadvantage is that the light is often poor and you will be
looking into the sun at some angles. The advantage is that with
a viewing field of almost 180 degrees, at least half the river will
be in decent to excellent light. You can walk either north as far
as the Pennsylvania line or south as far as the dam. Just north
of this access, and across the river, is the mouth of Glen Cove
and large numbers of gulls and terns frequently feed there. Many
will be on the other, inaccessible side of the river and require
a scope, but there will rarely be a shortage of birds to look at
in any season except summer. It is from this location that the Parasitic
Jaeger and the Pacific Loon were observed.
The conditions that produce the best birds are northeast winds and
occasional rain from mid-October through November. It is under these
conditions that scoters, Brant, and Red-throated Loons are most
frequently seen, and accounts for the only jaeger record, a single
Parasitic harassing gulls. It was also under those conditions that
more than 700 Red-throated Loons were found on one day, the highest
inland count in the history of the state.
Shorebirds: Conowingo Dam is one of the best places
to find shorebirds in Harford County, more of a testament to the
lack of habitat here than to the good numbers at the dam. In late
summer and fall, on days when there is little or no generation,
shorebirds can be found on the rock bars below the large island
opposite the parking lot. Often this requires walking the trail
down river from the parking lot. Numbers are never large but persistent
searching over the past five years has turned up a good list, including
American Golden-Plover, Short-billed Dowitcher, Ruddy Turnstone,
Stilt Sandpiper, Dunlin, White-rumped Sandpiper, Wilson's Phalarope,
and Sanderling. The birds are often difficult to find in the rocks
and the effort requires a good scope.
Waterfowl: The river holds good numbers of ducks
fall through spring. The birds most frequently found below the dam
are Mallard, Black Duck, Common Goldeneye, and Bufflehead. They
are scattered the length of the river and the largest numbers are
frequently found by walking the trail at the south end of the parking
lot. A favorite spot for puddle ducks is in the rocks directly across
from the base of the dam. Except when the water is extremely high,
there are always Mallards and Black Ducks there, and it is common
to find other species mixed in, especially Northern Pintail, American
Wigeon, Green-winged Teal, and Gadwall. All of the regularly occurring
puddle ducks have been found. Hooded Mergansers favor this area
also. All of the regularly occurring diving ducks have been found
below the dam and Common Mergansers move from above to below all
day in winter. Red-breasted Mergansers are regular but scarce above
and below the dam in migration and winter. A Harlequin Duck spent
time around the rocks and the large island one winter and another
was seen in early spring. Canada Geese are fairly common above and
below the dam at all seasons. Four swans, at least one of which
was a Trumpeter, spent much of the winter of 1998-99 in the river
below the dam, occasionally moving above the dam or farther down
river. They were most frequently seen in the rocks directly across
from the pavilion. Like all the waterfowl that favored the rocks,
they were sometimes hard to find and viewing birds there requires
a good scope. Although no bands were seen, it is possible the birds
originated from the ongoing release programs in the eastern Great
Other goodies: A fair list of non-gull rarities
has been reported from the dam and the trail below the parking lot.
A sampling includes: Brown Pelican, Harlequin Duck, Great Cormorant,
Mississippi Kite, Yellow-crowned Night-Heron, Royal Tern, Peregrine
Falcon, Olive-sided Flycatcher, Common Raven, Western Tanager, Mourning
Warbler, and Lincoln's Sparrow. Both Eastern Screech-Owl and Great
Horned Owl nest along the river and can be heard at dusk and dawn
some days. One to two Peregrine Falcons have spent the winter at
the dam since 1997-98. They are most frequently seen sitting in
the superstructure on top of the dam or chasing and catching Rock
Doves in front of the dam. When not actively hunting, they can be
very difficult to pick out.
Spring and fall: The trail
below the parking lot in an excellent place to look for flocks of
migrants in the spring and fall. Large numbers of warblers, vireos,
and flycatchers have been found on some days. Huge swallow flocks
begin forming in late summer, sometimes exceeding 10,000. Careful
scrutiny has turned up one or two Cliff Swallows every fall.
Summer: Great Blue Herons nest in the woods across
from the parking lot. Prothonotary Warblers are numerous on the
trail below the dam. Warbling Vireos are common nesters, as are
Eastern Kingbird, Orchard and Baltimore Orioles, Northern Parula,
and other riparian species. Wild Turkeys nest in the woods south
of the dam and are heard on occasion. The same is true for Pileated
Terns: Numbers begin to build in late summer. Large
numbers of Forster's Terns can be seen in the spring and fall and
fall numbers can exceed 1000 some years. A few Common Terns are
found every fall and spring. Black Tern has appeared in very small
numbers most falls. Least Tern has been found once. Caspian Terns
are regular in spring and fall. Royal Tern, rare this far north
in the Bay and inland, has been recorded once in the fall.
Cormorants: Large numbers of Double-crested Cormorants
can now be found in all but the coldest months. They have increased
substantially in the past decade and counts now regularly exceed
500 in the fall. In late fall Great Cormorant has been found the
past four years in the flocks of Double-cresteds. It is anticipated
that nesting by Double-crested, in the Great Blue Heron colony,
is only a matter of time.
Future highlights: There are a number of birds
that observers have anticipated at the dam but that have not yet
been recorded. All the gulls that have been recorded in Maryland
except for Yellow-legged, Ross', Black-tailed, and Sabine's have
been found and Sabine's is definitely on the watch list. So is the
North American race of Common Gull (Short-billed Gull). It has also
surprised observers that there is only one jaeger record and it
is assumed more will be found eventually. In an invasion year the
dam is a fine place for a Snowy Owl to take up residence. Rarer
birds that are on the watch list include Arctic Tern, Barrow's Goldeneye,
Ivory Gull, Gull-billed Tern, American Oystercatcher, White Pelican,
King Eider, and Sandwich Tern. All have some history in the upper
Bay or north of the dam in Pennsylvania.
Coverage: There are gullwatchers at the base of
the dam nearly every Saturday and Sunday from November through February.
Coverage during the week is irregular, as is coverage at other times
of the year. Eagle watchers are present nearly every weekend throughout
the year. They rarely pay attention to the other birds but sometimes
are familiar with what has been reported recently. Good birds found
at the dam appear on the Baltimore, Washington, Philadelphia, and
Central Pennsylvania hot lines.
More information about the
status of birds is available on this web site at the Annotated Checklist
of the Birds of Conowingo Dam.