years 1955-1958 show that the wintering popu- 
lation of waterfowl ranged from 10,900 in 1957 
to 77,300 in 1955, and averaged 48,500. During 
the 1958-59 season waterfowl numbers reached 
their peak during late fall. 
Proportions of the different species are 
shown in table 19. Diving ducks were more 
numerous in late fall, winter, andearly spring. 
Dabbling ducks predominated during the early 
fall flight. Canvasbacks and Ruddy Ducks were 
the most abundant in winter, making more 
than half of the population. American Widg- 
eons were of primary importance during the 
early fall flight, but rapidly declined there- 
after. Other important transients during both 
fall and spring flights included the Canvas- 
backs, Ruddy Ducks, American Coots, and 
scaup. The Central Potomac section is the 
only area within the Upper Chesapeake region 
where there normally are fairly large popula- 
tions of Gadwalls. 
LOWER POTOMAC SECTION 
Habitats 
The open estuarine bays are the most im- 
portant habitats in the Lower Potomac section, 
although the shoal-water zones containing 
submerged vegetation are narrow and quite 
limited. The lower part of the Potomac estuary, 
from the mouth of the river to Piney Point on 
the Maryland side and Sandy Point on the Vir- 
ginia side, and including the Coan, St. Marys, 
and Yeocomico Rivers, is a moderately saline 
estuarine bay. The portion of the estuary 
above this area extending to Cobb Island on 
the Maryland side and Pope Creek on the 
Virginia side, and including Breton, St. Clem- 
ent, and Nomini Bays, is typically brackish. 
Other habitats are of minor importance in 
this section and quite restricted in size. 
Small areas of salt estuarine bay marsh are 
scattered along the river, the largest on St. 
George Island. Occasional patches of brackish 
estuarine river marsh also are present along 
some of the smaller tributaries. Locally, and 
especially in the St. Marys River area, large 
grain fields border the shores of the estuaries, 
Waterfowl 
There are comparatively few waterfowl in 
the Lower Potomac section. The majority are 
diving ducks and other open-water species. 
Good-sized flocks of Canada Geese, and 
smaller numbers of dabbling ducks, occur lo- 
cally near grain fields. Counts made in the 
January inventory, 1955-58, ranged from 
2,600 in 1956 to 60,800 in 1955, averaged 
32,000. During the 1958-59 season, the peak 
population was reached in mid-winter and was 
maintained at a high level through early 
March. 
24 
Proportions of the different species are 
shown in table 20. Canada Geese and American 
Widgeons made up the greater part of the 
early fall flight of waterfowl. The diving ducks 
were especially important in late fall, winter, 
and early spring. The principal waterfowl 
species were Canvasbacks, Redheads, scaup, 
Common Goldeneyes, Buffleheads, Oldsquaws, 
and Ruddy Ducks. 
PATUXENT RIVER SECTION 
Habitats 
The principal habitats in the Patuxent River 
section are the open estuarine bays between 
the mouth of the river and Deep Landing, and 
the estuarine river marsh extending about 17 
miles from Deep Landing toa point 14 miles 
above Hills Bridge. The fresh-water portion 
of the marsh is the largest of its type in the 
Upper Chesapeake region, occupying a little 
more than 2,000 acres (including the river 
channel), 
The open estuarine bays include two fairly 
distinct sectors. Water is moderately saline 
from the mouth of the river upstream to 
Point Patience. Sago pondweed and the more 
characteristic salt-water species grow in this 
sector. The estuarine bay above Point Pa- 
tience is typically brackish. It contains fairly 
large beds of submerged vegetation, except 
for the portion above Swanson Creek, where 
turbidity is great enough to limit the develop- 
ment of aquatic plants. The estuarine river 
marsh has three natural sectors: a brackish 
portion, from Deep Landing to (but not including) 
Hall Creek; atransitional brackish-fresh area, 
from Hall Creek to Lyons Creek; and a fresh 
portion, above Lyons Creek, 
Waterfowl 
A great variety of diving ducks and dabbling 
ducks occur regularly in this section. The 
total populations, however, are lower than 
would be expected, judging by the excellent 
habitat conditions throughout. Excessive hunt- 
ing pressure and other human disturbance may 
be responsible for the apparent discrepancy 
between habitat conditions and numbers of 
waterfowl, 
January inventory data during the years 
1955-58 show that the wintering population 
ranged from 4,100 in 1958 to 72,100 in 1956, 
averaged 29,900. During the 1958-59 season, 
the population peak (14,800) was reached in 
late fall. 
Proportions of the different species are 
shown in table 21. Canvasbacks and scaup were 
the principal wintering waterfowl. Fairly large 
numbers of Whistling Swans, Mallards, Black 
Ducks, Redheads, Common Goldeneyes, Buf- 
fleheads, Ruddy Ducks, and American Coots 
