The objective of this report is to discuss the present 
status of the major waterfowl species in the Chesapeake Bay 
based on analysis of 39 years (1948-86) of winter survey data. 
Each waterfowl species was compared to the status of populations 
in the Atlantic Flyway and North America to determine if changes 
detected in the Chesapeake Bay were due to conditions in the 
Bay, or to Flyway or Continental population levels. 
The assistance of Edward Burton with the preparation of 
graphs and of Valerie Lumsden in word processing is appre¬ 
ciated. Robert Munro assisted with analysis and interpretation 
of data. Drafts of this manuscript were reviewed by Ronald 
Eisler, James Fleming, Robert Munro, and Vermon Stotts. 
METHODS 
All survey data used in this report were obtained from un¬ 
published data in files of the Office of Migratory Bird Manage¬ 
ment, U.S. Fish and Wildlife Service (USFWS), Laurel, Maryland. 
The Chesapeake Bay counts represent counts in Maryland and 
Virginia combined. Aerial surveys were flown at low levels 
(25-100 m) with single engine aircraft of the USFWS and various 
State wildlife agencies. Surveys in the Chesapeake Bay have 
been conducted since 1948 in early January when waterfowl popu¬ 
lations are more stable and concentrated than at other times 
during the winter. The average number of waterfowl during the 
1980s was compared with the average number during years before 
1980 to determine present status of waterfowl. Survey data in 
graphs are presented as 5-year averages (except for the 4-year 
period, 1983-86) to minimize annual fluctuations and to empha¬ 
size long-term trends. Further discussion on survey techniques 
and data analysis are given in Perry et al. (1981). 
RESULTS AND DISCUSSION 
Tundra Swan 
Tundra swan (Cygnus columbianus) populations in the Chesa¬ 
peake Bay have been variable during the 39-year period of aerial 
surveys (Table 1? Fig. 1). Lowest numbers occurred at the 
beginning of the surveys in 1948 (18,216) and then peaked in 
1955 (75,854). Populations were also high in the mid-1960s. 
The long-term average population was 36,710. The average re¬ 
corded during the 1980s was 35,065 which was only 5% less than 
the pre-1980 average of 37,070. 
In the early years of the surveys, swans in the Chesapeake 
Bay were found mostly in the lush aquatic vegetation beds in the 
central portions of the Eastern Shore. In the late 1960s and 
early 1970s, however, tundra swans began to feed in agricultural 
fields on waste corn and winter cover crops. Although most of 
this feeding occurred on the Eastern Shore one large flock of 
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