These drastic habitat changes have had con- 
spicuous local effects, but probably have not 
greatly reduced the population of the region 
as a whole. Any general adverse effect on 
waterfowl populations has been partially off- 
set in a few areas by well-planned programs 
of habitat improvement. These local programs 
have benefited geese and dabbling duck popu- 
lations, but so far very little has been done 
to improve habitat conditions for diving ducks. 
However, excellent habitat still prevails in 
many parts of the Upper Chesapeake region, 
and it probably is extensive enough to support 
the numbers of waterfowl available to use this 
region during recent years. Further destruc- 
tion or impairment of waterfowl habitat must 
be halted if a reduction in use of the Upper 
Chesapeake area is to be avoided. 
Federal, State, and private agencies are 
accelerating their programs toward preserv- 
ing the waterfowl habitats that still remain. 
The better-quality areas are being given the 
highest priority. Data from the present study 
indicate that the better-quality habitats in the 
study area include the brackish estuarine bays 
of the Chester River, Eastern Bay, Choptank 
River, and their tributaries; the fresh estua- 
rine bay of the Susquehanna Flats; the slightly 
brackish estuarine bay of the Potomac River 
and its tributaries; the fresh and brackish 
estuarine bay marshes of the Blackwater- 
Nanticoke section; and estuarine river marshes 
along the Nanticoke, Choptank, and Patuxent 
Rivers. 
Food habits of waterfowl in the Upper 
Chesapeake region vary greatly from one 
species to another and from one habitat to 
another, Variations in foods consumed by any 
given species appear to be due to differences 
in availability of foods and so are influenced 
by habitat and seasonal changes. For the 
majority of waterfowl, widgeongrass probably 
is the most important single waterfowl food 
in the Upper Chesapeake region, and clasping- 
leaf pondweed probably is second most im- 
portant. Corn also is very important to many 
kinds of waterfowl. Other food plants important 
locally are wildcelery, eelgrass, Olney three- 
square, and dotted smartweed. The more 
important animal foods in the region are: 
63 
the bivalve Baltic macoma (Macoma balthica), the 
little surf clam (Mulinia lateralis), the saltmarsh 
snail (Melampus bidentatus), various tiny gastropod 
mollusks (including Littoridinops sp., Bittium sp., 
and Acteocina canaliculata), amphipod crustaceans 
(Gammaridae), mud crabs (Xanthidae) and 
midge larvae (Chironomidae), 
Human disturbance reduces use by water- 
fowl of many areas that otherwise are suitable. 
Heavy hunting pressure, in particular, often 
is important. Disturbance caused by speed 
boats used for recreation, commercial fishing 
vessels, or large concentrations of other boats 
frighten waterfowl from an area. Artillery 
firing, target bombing, and low-flying planes 
and helicopters also reduce waterfowl use. 
Waterfowl of open-water bays and estuaries 
are especially influenced by hunting, fishing, 
boating, and similar human activities. 
The distribution of the waterfowl] kill, in 
general, was closely correlated with the dis- 
tribution of populations. The greatest kill 
occurred along the central eastern shore of 
Chesapeake Bay in the Chester River, Eastern 
Bay, and Choptank River sections. Other im- 
portant areas included the Lower Eastern 
Shore and Central Potomac sections. The 
Lower Eastern Shore section was unique in 
that the kill there of several species in- 
cluding Canada Geese and Pintails was un- 
usually high in relation to their populations. 
In contrast, the proportional relationship be- 
tween kill and populations of Canada Geese 
and Mallards in the Blackwater-Nanticoke 
section and of Black Ducks, Pintails, and 
American Widgeons in the Chester River 
section indicates that the local hunting pres- 
sure on these particular species must have 
been relatively low. The kill of certain water- 
fowl such as Canvasbacks and American Widg- 
eons was widely distributed over the Upper 
Chesapeake region, whereas the kill of others, 
such as Redheads and Pintails, was muchmore 
localized. 
A study of the harvest areas throughout 
North America, of waterfowl populations banded 
in the Upper Chesapeake region, showed that 
the mid-Atlantic states region was the principal 
harvest area for most species, and that the 
greatest concentration of kill was in Maryland. 
