species. Other plant foods that are fairly 
important include: hightide-bush (seeds), salt- 
marsh bulrush (seeds), and muskgrass. Seeds 
of twigrush also are frequently taken although 
this species ordinarily does not growinbrack- 
ish estuarine bay marshes. However, twigrush 
seeds are common in the windrows of vege- 
tative debris along the creeks and ponds of 
the drainage systems; apparently, these seeds 
drift down from fresh estuarine bay marshes 
located on the upper watersheds of many of 
the tidal streams. Invertebrates commonly 
eaten by one or more kinds of ducks include 
the saltmarsh snail (Melampus bidentatus), the 
tiny gastropod Litloridinopssp., and copepods, 
Black Ducks often feed on small fish (chiefly 
Poecilidae) in midwinter, but prefer larvae 
and pupae of mosquitoes (Culicidae) insummer. 
Waterfowl Harvest 
The number of waterfowl bagged by mem- 
bers of the Elliott Marsh Gun Club from 
1955 to 1958 is shown in table 11. The hunted 
area was a 700-acre tract of brackish estua- 
rine bay marsh in southern Dorchester County. 
Six hundred and forty-eight waterfowl were 
taken during the 4-year period. One hundred 
and eighty-two of these were bagged in 1955, 
203 in 1956, 112 in 1957, and 151 in 1958, 
The average number of waterfowl per man 
day was 2.3, varying from 1.7 in 1957 to 2.8 
in 1955. American Widgeons and Black Ducks 
together made up 72% of the total, and Mallards 
made up 9% of the total. 
FRESH ESTUARINE BAY MARSHES 
Fresh estuarine bay marshes (fig. 3) have 
developed on broad, shallow estuarine flats 
that are flooded by fresh or slightly brackish 
tidewaters. This habitat occupies about 30,000 
acres in the Upper Chesapeake region. Dif- 
ferences in depth between mean low tides 
and mean high tides normally are quite narrow 
(1 to 14 feet), The tidal streams of the drainage 
systems usually are broad and poorly defined 
and often merge imperceptably into the nu- 
merous large connecting ponds. Marshes of 
this type occur mainly in two widely separated 
areas, The firstarea comprises approximately 
16,400 acres in Dorchester County, Maryland, 
In this area, the marshes are along the upper 
portions of the Blackwater. River and its two 
tributaries (Meekins Creek and Little Black- 
water River), along the upper portion of Ireland 
Creek, and in the vicinity of Savannah Lake. 
The second area is in Baltimore and Harford 
Counties, Maryland. The marshes there occupy 
about 9,300 acres along the necks of land that 
extend into Chesapeake Bay. In a few other 
places, small marshes are scattered along 
the shores of Chesapeake Bay behind narrow 
barrier beaches, 
17 
Vegetation 
The characteristic plants of fresh estuarine 
bay marshes are: 
Primary species 
Narrowleaf Cattail 
Sago Pondweed 
Dwarf Spikerush 
Olney Three-square 
Common Three-square 
White Waterlily 
Rosemallow 
Secondary Species 
Muskgrass Softstem Bulrush 
Marsh Fern Twigrush 
Royal Fern Duckweed (Lemna minor) 
Blue Cattail Pickerelweed 
Southern Cattail Iris 
Claspingleaf Pondweed Dotted Smartweed 
Widgeongrass Coontail 
Wildcelery Pinnate Watermilfoil 
Saltgrass Slender Watermilfoil 
Cyperus (C. filicinus) 
Common Spikerush 
Water Pennywort 
Olney three-square dominates very exten- 
sive areas in Dorchester County and also is 
dominant in most other fresh estuarine bay 
marshes. It occurs in nearly pure stands or 
in associations with rosemallow and other 
subdominant species. It is predominant in 
broad zones closest to the drainage channels. 
Narrowleaf cattail, withits associated species, 
usually is restricted to areas where the water 
level is more stable. It is particularly com- 
mon near the headwaters of the tributary 
streams and in areas along Chesapeake Bay 
that are protected by narrow barrier beaches. 
Common three-square usually dominates the 
marsh meadows that are frequent in the more 
shallow areas along the margins of themarsh. 
Common spikerush and other species, suchas 
softstem bulrush, twigrush, iris, dotted smart- 
weed, and marsh fern may be quite common 
locally in the marsh meadows. 
Vegetation of the ponds and creeks is vari- 
able. Dwarf spikerush usually is common on 
mud bars or shallow flats that are often ex- 
posed at low tide. White waterlilly, and oc- 
casionally water pennywort, make dense growth 
in ponds and creeks where the water level is 
relatively stable, as it often is toward the 
upper limits of the marsh. Submerged aquatic 
plants are comparatively scarce in the exten- 
sive marshes along the upper Blackwater 
River, because the water is darkened by or- 
ganic stain, which reduces the penetration of 
sunlight, Sago pondweed is widely distributed 
in the marshes in Dorchester County except 
for the Blackwater River area. Other sub- 
merged species are common locally. Extensive 
beds of mixed species, including wildcelery, 
claspingleaf pondweed, sago pondweed, slender 
milfoil, and pinnate milfoil occur at Savannah 
Lake, one of the larger marsh ponds. Avariety 
