bays extend from Spesutie Island to Gunpowder 
Neck; they include the Bush River estuary 
and the upper half of the Gunpowder River 
estuary (see map, fig. 3). The slightly brack- 
ish estuarine bays extend from Gunpowder 
Neck to Bodkin Island; they include the lower 
half of the Gunpowder River estuary and the 
Middle, Back, and Patapsco Rivers estuaries. 
This section also contains fairly large 
areas of tidal marsh. There are three major 
types. Fresh estuarine bay marshes occur 
on the 'necks'' extending into Chesapeake Bay 
between Spesutie Island and the Middle River. 
A large fresh estuarine river marshis located 
at the upper limits of the Patapsco River 
estuary. It has been modified somewhat by 
earth fill and trash disposal. Smaller fresh 
estuarine river marshes lie along the upper 
Bush and Gunpowder estuaries. Small brack- 
ish estuarine river marshes occur along 
streams near the outer bay shore in a few 
scattered areas between Gunpowder Neck and 
Bodkin Island. 
Food plants are abundant throughout the 
greater part of this section. Locally, indus- 
trial pollution has caused extensive damage 
to submerged plants. Small beds of the intro- 
duced waterchestnut and Eurasian watermilfoil 
have become established recently. Unless 
these plants are eradicated soon, they prob- 
ably will spread and crowd out natural beds 
of submerged vegetation. 
Waterfowl 
Many transient diving ducks and Whistling 
Swans occur in this section, as do fairly 
large numbers of transient dabbling ducks. 
Numbers of wintering waterfowl vary greatly 
from year to year, depending on the weather. 
Human disturbance, in the form of excessive 
boating and artillery firing on the military 
reservations, appears to be increasing. Dis- 
turbance may be responsible for the reduction 
in waterfowl populations noticeable during 
recent years. 
January inventory data during the years 
1955-58 show that the wintering population 
ranged from 4,000 in 1956 to 58,100 in 1955, 
averaged 34,400. During the 1958-59 season, 
the population peak was reached in late fall. 
Proportions of the different species are 
Shown in table 24. Ruddy Ducks are pre- 
dominant. Other waterfowl that are fairly 
abundant include Canvasbacks, Redheads, 
scaup, Whistling Swans, and Canada Geese. 
SUSQUEHANNA FLATS SECTION 
Habitats 
The fresh estuarine bay habitat is at its 
best in this section and is the only extensive 
habitat. Tremendous beds of a variety of 
26 
submerged plants are widespread through the 
section. 
Waterfowl 
Great numbers of transient waterfowl con-~ 
centrate on the Susquehanna Flats and the 
adjoining estuary, the Northeast River. The 
huge flocks of Canvasbacks sometimes contain 
nearly half of the total continental population 
of the species. Large numbers of other diving 
ducks, and many swans, geese, dabbling ducks, 
and coots stop in this area during migration. 
Boating and hunting both have increased in 
recent years, and, as a result, most water- 
fowl do not remain in the area as long as 
they did formerly. 
January inventory data during the years 1955- 
58 show that numbers of wintering waterfowl 
at the Susquehanna Flats ranged from 1,500 
in 1956 to 72,300 in 1955, averaged 28,400. 
This extreme variation is largely a reflection 
of changes in ice conditions on the flats from 
year to year. Proportions of the different 
species are shown in table 25. During the 
1958-59 season, the early December population 
was unusually low and probably was correlated 
with the abnormally low temperatures at that 
time. Peak population numbers are reached 
during late November and early December of 
most years. On December 7, 1947, more than 
100,000 Canvasbacks and 25,000 scaup were 
counted (with the aid of a telescope) from 
three observation points along the shore; by 
December 20, only 44,000 Canvasbacks could 
be counted and scaup had disappeared entirely. 
American Widgeons are the principal water- 
fowl in the Susquehanna Flats section during 
the early fall flight in October. Fairly large 
numbers of Pintails (500 to 10,000) alsoarrive 
on the flats during September, and frequently 
remain through the early part of October, 
Redheads and Canvasbacks usually are pre- 
dominant during late fall and winter, when | 
fairly large numbers of Whistling Swans, 
Canada Geese, Black Ducks, Common Golden- 
eyes and Buffleheads also are present. Red- 
heads, Canvasbacks, and Lesser Scaup are the 
commonest waterfowl in spring. American 
Coots often are common in late March and 
April, and occasionally are fairly common 
in the fall. Shore counts from numerous 
observation points showed a total of 11,400 
American Coots on March 31, 1955. 
UPPER EASTERN SHORE SECTION 
Habitats 
The principal areas of the Upper Eastern 
Shore section are the fresh-water estuarine 
bays of the Sassafras, Elk, and Bohemia 
Rivers. The river waters are quite turbid or 
heavily silted so that there are relatively few 
