Nearly one-half of the total kill apparently 
occurs in the Choptank River and Blackwater- 
Nanticoke sections, The greatest local con- 
centrations of kill also are within these 
sections, in the estuarine river marshes and 
wooded swamps along the Choptank and Nanti- 
coke Rivers and their tributaries. The re- 
maining kill is in areas that are fairly well 
distributed over estuarine river marshes and 
wooded bottomlands of the other sections. The 
10% kill in the coastal plain interior is 
proportionally much higher than for any other 
species of waterfowl. 
Kill data arranged by months showed that 
about 70% of the kill was in November, 30% 
in December, and none in January. 
REDHEAD 
Aythya americana (Eyton) 
The transient and wintering Redheads in the 
Upper Chesapeake region are somewhat more 
localized and sporadic than most other water- 
fowl. In a few areas they often are common 
or even abundant, whereas in many other 
areas they are rare or absent. January inven- 
tories for the years 1953-58 show that the 
wintering population ranged from 30,000 in 
1958 to 106,200 in 1956, averaged approxi- 
mately 66,200. This average figure represents 
about 8% of the continental wintering popula- 
tion and about 44% of the Atlantic population. 
The fall migration usually is during the period 
of October 5-15 to December 15-25, with the 
peak between November 10 and December 10. 
The normal spring migration period extends 
from March 1-10 to May 1-10, with the peak 
between March 15 and April 20. 
Habitats 
Wintering Redheads are most numerous in 
brackish estuarine bays, in areas that contain 
extensive beds of claspingleaf pondweed, widg- 
eongrass, sago pondweed, and eelgrass, Fairly 
large numbers also occur inmoderately saline 
estuarine bays in the Tar Bay and Honga 
River areas of the Lower Eastern Shore 
section, where the predominant submerged 
plants are sago pondweed, widgeongrass, and 
eelgrass. 
January inventories of 1955-58 showed the 
ecological distribution of wintering popula- 
tions as follows: brackish estuarine bays - 
64%; fresh estuarine bays - 14%; salt estuarine 
bays - 12%; slightly brackish estuarine bays - 
8%; and coastal bays - 2%. Thus wintering 
populations showed a definite preference for 
brackish-water types. 
During the spring and fall migration periods, 
Redheads seem to prefer fresh and slightly 
brackish estuarine bays, where they con- 
centrate in localities with an abundance of 
48 
submerged plants, particularly wildcelery and 
naiad. Many migrants also occur on brackish 
estuarine bays that contain large quantities of 
claspingleaf pondweed and widgeongrass. Afew 
small migrant flocks occasionally are present 
on interior impoundments, or, rarely, in the 
estuarine marshes, 
Seasonal distribution during the 1958-59 
season is shown in table 94. Fresh estuarine 
bays were the major Redhead habitat during 
the migration periods, and the brackish es- 
tuarine bays were most important in winter, 
Salt estuarine bays also were used moderately 
in winter. These shifts in habitat probably 
are related to the relative severity of weather 
and ice conditions in different parts of the 
region, 
Biogeographic Sections 
The average distribution of Redheads during 
the January inventories of 1955-58 is shown 
in table 95. The Choptank River section is 
the most important wintering area in the 
region, About two-thirds of the Upper Chesa- 
peake population was in the various eastern 
shore sections extending from the Pocomoke 
River to the Chester River. Most of the re- 
maining birds were fairly evenly divided 
between the northern portion of Chesapeake 
Bay (Upper Eastern Shore, Susquehanna Flats, 
and Upper Western Shore sections) and the 
western shore area (Central Western Shore, 
Patuxent River, Central Potomac and Lower 
Potomac sections), 
Intensive aerial population surveys during 
the fall, winter, and early spring of the 1958-59 
season showed seasonal changes in numbers 
of birds (table 96). The Susquehanna Flats sec- 
tion contained practically all of the Redheads 
in early November and about three-fourths of 
them during the first half of March. The ma- 
jority of the early December population was 
concentrated in the Upper Western Shore 
section. Wintering birds were most numerous 
in the Eastern Bay and Choptank River sec- 
tions. The greatest local concentrations of 
Redheads were recorded on the Susquehanna 
Flats, the upper Eastern Bay, and the Honga 
River areas, and along the north shore of the 
lower Choptank River. During other years, 
large local concentrations have been observed 
in the Gunpowder-Middle River area of the 
Upper Western Shore section. 
Food Habits 
The gullet and gizzard food contents of 
99 Redheads were examined. Data for 98 of 
these are shown in tables 97-99, In addition 
to these, a single bird was collected on an 
interior impoundment of Prince Georges 
County on March 16, 
