SPECIES ACCOUNTS 
Detailed accounts for each species of water- 
fowl occurring in the Upper Chesapeake re- 
gion are presented in the following pages. 
Accounts of the different species vary greatly 
in the amount of information they contain, 
for all species were not studied with equal 
intensity. Discussions are organized as fol- 
lows: introduction (size of the Chesapeake 
population and its proportion in the Atlantic 
and continental population, breeding and mi- 
gration dates), habitats, biogeographic sec- 
tions, food habits, local distribution of hunting 
kill, and harvest areas of birds banded in the 
Upper Chesapeake region. Methods of present- 
ing food-habits and band-recovery data are 
discussed in the introduction. 
WHISTLING SWAN 
Olor columbianus (Ord) 
Large numbers of Whistling Swans migrate 
through, and winter in, the Upper Chesapeake 
region, January inventories for the years 
1953-58 show that the wintering population 
ranged from 17,000 in 1958 to 71,600 in 1955, 
averaged approximately 39,100. This average 
figure represents about 44% of the continental 
population and 77% of the Atlantic population. 
The fall migration usually is during the period 
from October 15-25 to November 20-30, with 
the peak between October 25 and November 
20. The normal spring migration extends from 
March 1-10 to April 20-30, with the peak 
between March 10 and April 5. Whistling Swans 
normally are in flocks of 5 to 200 or more 
individuals. 
A detailed report concerning the local dis- 
tribution, numerical status, habitat, and food 
habits of Whistling Swans in the Upper Chesa- 
peake region has been published (Stewart and 
Manning, 1958), The present report contains 
additional information. 
Habitats 
Whistling Swans generally are restricted to 
fairly extensive areas of open estuarine waters 
no more than 5 feet deep. The larger con- 
centrations are in places where submerged 
plants are abundant. Swans ordinarily do not 
inhabit the salt estuarine bays except locally. 
Small numbers may occur in the Tar Bay and 
Honga River areas and in the vicinity of 
Bloodsworth and South Marsh Islands. Small 
numbers also occur on some of the larger 
ponds of the fresh and brackish estuarine 
bay marshes in Dorchester County. The great- 
est wintering concentrations of swans normally 
occur in the brackish estuarine bays. Rela- 
tively small numbers occur in the fresh and 
31 
slightly brackish estuarine bays, which are 
subject to frequent freezing. 
January inventories of 1955-58 showed the 
average ecological distribution of wintering 
populations as follows: brackish estuarine 
bays - 76%; salt estuarine bays - 9%; fresh 
estuarine bays - 8%; slightly brackish estua- 
rine bays - 6%; coastal impoundment-bay com- 
plex - 1%; and fresh and brackish estuarine 
bay marshes -+%, 
During the spring and fall migration periods, 
Whistling Swans occur regularly in fairly 
large numbers throughout open shallow tide- 
water areas of fresh and slightly brackish 
estuarine bays. Scattered individuals or small 
flocks occasionally are found for brief periods 
on some of the larger reservoirs and im- 
poundments of the coastal plain interior. 
Seasonal distribution during the 1958-59 
season is shown in table 33. The majority 
of the swans inhabited brackish estuarine 
bays during late fall, winter, and earlyspring. 
A large proportion of the earlier arrivals 
during the fall migration occupied the fresh 
estuarine bays. 
Biogeographic Sections 
The average distribution of Whistling Swans 
during the January inventories of 1955-58 is 
shown in table 34, 
Sixty-three percent of the average winter- 
ing population was along the central portions 
of the eastern shore of Chesapeake Bay in 
the Chester River, Choptank River, and Eastern 
Bay sections. Most of the remaining birds 
(34% of the total) were distributed over the 
Central Western Shore, Lower Eastern Shore, 
Upper Western Shore, Susquehanna Flats, Low- 
er Potomac, and Central Potomac sections. 
Population surveys during the fall, winter, 
and early spring of the 1958-59 season showed 
seasonal changes innumbers of birds (table 35), 
The greatest populations of migrant and winter- 
ing swans were along the central eastern shore 
in the Choptank River, Eastern Bay, and Ches- 
ter River sections. Large numbers used the 
Susquehanna Flats, particularly during spring 
migration. Areas of greatest local concentra- 
tions included the lower Choptank River (es- 
pecially along the north shore), the central 
Chester River, and upper Eastern Bay. Fairly 
large numbers also were found in the lower 
Chester River, central Choptank River, Miles 
River, Central Western Shore, Upper Western 
Shore, and Central Potomac areas. 
Food Habits 
The gullet and gizzard food contents of 50 
swans were examined (table 36), 
