Leaves, stems, and roots of submerged 
plants appear to be the foods of paramount 
importance to Whistling Swans in all areas 
where the birds occur in greatest concentra- 
tions. Wildcelery apparently is the principal 
food in fresh estuarine bays, whereas widg- 
eongrass and sago pondweed are utilized to 
the greatest extent in the critical brackish 
estuarine bay communities. Certain species 
of thin-shelled bivalve mollusks, particularly 
the Baltic macoma (Macoma balthica) and the 
commercially valuable long or ''soft-shelled'' 
clam (Mya erenaria) are also consumed in con- 
siderable quantities in the brackish estuarine 
bays. The small population of swans on the 
estuarine bay marsh ponds of Dorchester 
County shows their adaptability by consuming 
not only widgeongrass but other entirely dif- 
ferent types of foods, including rootstalks 
and stems of certain emergent marsh plants. 
CANADA GOOSE 
Branta canadensis (Linnaeus) 
Canada Geese are common, locally abundant, 
transients during spring and fall in most of 
the Upper Chesapeake region, Large num- 
bers remain throughout the winter in certain 
areas, particularly on the Eastern Shore. 
January inventories for 1953-58 show that the 
wintering population ranged from 95,400 in 1958 
to 269,100 in 1955, averaged approximately 
189,600. This average figure represents about 
18% of the continental population (excluding 
the Cackling Goose) and about 45% of the At- 
lantic population, The fall migration usually 
is during the period of September 25 - October 
5 to November 20-30, with the peak between 
October 15 and November 5. The normal 
spring migration extends from February 15- 
25 to April 15-25, with the peak between 
March 10 and April 10. . 
Habitats 
Extensive agricultural areas adjacent to 
open, shallow expanses of fresh, slightly 
brackish, or brackish estuarine bays appar- 
ently are the optimum habitat of Canada Geese 
in the Upper Chesapeake region. These habitat 
conditions are widespread along the eastern 
shore in the area extending from the Bohemia 
River to the Choptank River. Approximately 
70% of the average wintering population in the 
Upper Chesapeake region during 1955-58 was 
in this area. The geese ordinarily fed in the 
larger grain fields and both fed and roosted 
on the shallow estuarine waters. Large num- 
bers of geese also roosted locally on the 
fresh-water impoundments that are scattered 
through the farmlands. 
Fairly large numbers of Canada Geese also 
were found throughout the extensive estuarine 
32 
bay marshes below the Choptank River and 
in the coastal salt marshes, In the winters of 
1955-58, approximately 16% of the Upper Ches- 
apeake population occurred in the fresh and 
brackish estuarine bay marshes of the Black- 
water-Nanticoke section; about 9% occurred 
in the salt estuarine bay marshes of the 
Lower Eastern Shore section; and about 3% in 
or near the salt marshes of the Coastal sec- 
tion. The geese fed in both fields and marshes, 
In the marshes they usually fed in associations 
of common three-square, Olney three-square, 
or saltmarsh cordgrass, or in shallow ponds 
containing submerged plants. They roosted 
on the larger marsh ponds or impoundments 
as well as on adjacent estuaries or coastal 
bays. 
Habitats suitable for Canada Geese are 
rather limited in the various western shore, 
Patuxent River, and Potomac sections. Most 
of the agricultural fields in these sections 
are small and somewhat scattered, and the 
shallow zones of the adjacent estuaries usually 
are quite narrow. Most of the marshes are 
small isolated patches. The greatest concen- 
tration of geese in the areas is in the vicinity 
of St. Marys River in St. Marys County. 
Biogeographic Sections 
The average distribution of Canada Geese 
during the January inventories of 1955-58 is 
shown in table 37. Approximately 95% of the 
population occurred in the sections along the 
eastern shore of Chesapeake Bay, about 3% 
were in the Coastal section, and only 2%in the 
various western-shore sections (including the 
Susquehanna Flats and Potomac River sec- 
tions). Greatest concentrations (about one- 
fourth of the total) were in the Chester River 
section. 
Seasonal changes in numbers during 1958-59 
are shown in table 38. The Chester River and 
Upper Eastern Shore sections had relatively 
high populations during all five surveys. The 
Eastern Bay and Choptank River sections had 
large numbers of geese during November, 
December, January, and March, but relatively 
small numbers during October. Comparatively 
large numbers were in the Blackwater-Nan- 
ticoke section during October and November. 
Greatest local concentrations were in the 
central Chester River, Sassafras River, and 
lower Choptank River (chiefly north shore) 
areas. 
Food Habits 
The gullet and gizzard food contents of 15 
Canada Geese were examined (table 39), Nu- 
merous field observations, plus the limited 
data from analyses, indicate that waste corn 
in the fields is the food of primary importance 
for Canada Geese in areas where extensive 
