by census data listed by Stewart 
(1958), 
The breeding season generally extends from 
mid-March to early September, with the peak 
between early April and late June. Extreme 
egg dates (217 nests) range from March 9 (V. 
D, Stotts) to August 24; estreme dates for 
downy young (54 broods) range from April 8to 
late September (V. D. Stotts), Comparative 
sexual development and pairing throughout the 
year are described by Stotts (1958b). 
Fall migration usually is during the period 
of September 10-20 to December 1-10, with the 
peak between October 20 and November 25, 
The normal spring migration extends from 
February 15-25 to April 15-25, with the peak 
between February 25 and March 25, 
Habitats 
Black Ducks are characteristic of a greater 
variety of habitats within the Upper Chesa- 
peake region than any other waterfowl, 
During migration and wintering periods, 
they occupy habitats ranging from the bottom- 
lands and freshwater impoundments of the 
coastal plain interior to the coastal salt 
marshes, including estuarine river marshes as 
well as fresh, brackish, and salt estuarine 
bay marshes, They also are common in the 
complex of estuarine bays and agricultural 
fields. Ecological distribution during the 1958- 
59 season is shown in table 54. From one-half 
to two-thirds of the population occupied the 
shallow estuarine bays and adjoining agricul- 
tural fields of the Chester River, Eastern 
Bay, Choptank River, and Upper Eastern Shore 
sections. They were more common in the 
moderately brackish estuaries of the Chester 
River, in the typical brackish estuaries of 
the Eastern Bay and Choptank River sections, 
and in the fresh and slightly brackish estuaries 
of the Upper Eastern Shore section than 
they were in other areas. Fairly large num- 
bers were present inthe estuarine bay marshes 
of the Blackwater-Nanticoke and Lower East- 
ern Shore sections, and in the coastal salt 
marshes. During late fall, winter, and early 
Spring of the 1958-59 season, they seemed to 
prefer the coastal salt marshes and salt 
estuarine bay marshes to the estuarine fresh 
and brackish bay marshes. Many were present 
in the estuarine river marshes during the 
fall migration (October, November) and during 
the spring migration (March), 
The largest breeding populations are along 
the margins of shallow brackish open estu- 
aries of the Chester River, Eastern Bay, and 
Choptank River sections and in the extensive 
brackish estuarine bay marsh of the Black- 
water-Nanticoke section. Fairly large breeding 
populations also are present in the salt es- 
tuarine bay marshes of the Lower Eastern 
Shore section. Scattered pairs inhabit the 
coastal salt marshes, the fresh estuarine 
at 
bay marsh, and the various areas of estuarine 
river marsh. A few pairs have become es- 
tablished locally in the vicinity of freshwater 
impoundments or along river bottomlands of 
the coastal plain interior. Concentrations of 
breeding Black Ducks occur on some of the 
islands and isolated points of land in the 
shallow estuarine waters of the Chester River, 
Eastern Bay, and Choptank River sections. 
In 1953, Stotts (1956) found 79 breeding pairs 
on Parson and Bodkin Islands (located in 
Eastern Bay). This was a density of about 58.5 
pairs per 100 acres of island since the two 
islands together contained 135 acres, However, 
since the shallow estuarine waters surrounding 
the islands were used extensively for feeding, 
the true density, considering all habitats that 
were utilized, was much lower. In 1956, I 
found 53 pairs (5.3 pairs per 100 acres) of 
Black Ducks in a census of 1,000 acres of 
brackish estuarine bay marsh in Dorchester 
County within the Blackwater-Nanticoke Sec- 
tion. 
Black Ducks construct their nests in avari- 
ety of situations. In the brackish estuarine 
bay marshes of the Blackwater-Nanticoke 
section, 7 nests were found in big-cordgrass 
border along tidal creeks; 2 in saltmeadow 
cordgrass association; 2 in Olney three- 
square--saltmeadow cordgrass association; 
2 in saltmarsh cordgrass--hightide-bush as- 
sociation; 1] in needlerush association; 1 in 
switchgrass association; and 1 in the brushy 
margin of an island. Fourteen nests were found 
in other habitats: coastal embayed marshes, 
salt estuarine bay marshes, andinterior areas. 
Nest sites were similar to those in the brack- 
ish marshes. Black Ducks nesting along the 
margins of estuarine bays in the Chester 
River, Eastern Bay, and Choptank River sec- 
tions often build their nests in marginal 
thickets, including tangles of Japanese honey- 
suckle. 
Biologists of the Maryland Game and Inland 
Fish Commission found a total of 356 nests 
on three small islands in the Kent Island 
area during the 1953 and 1954 breeding sea- 
sons (Stotts, 1955), About 80% of thenests were 
in wooded areas, near the margins; next 
greatest numbers were in marshes and cul- 
tivated fields, Stotts (1958a) found that Black 
Ducks often use offshore hunting blinds as 
nesting sites. In a survey of the Upper Chesa- 
peake area during 1957-58, he found that 106 
offshore blinds, 10% of the 1,009 that were 
inspected, were used by nesting ducks (chiefly 
Black Ducks), Ducks apparently preferred 
blinds covered or ‘'brushed!'' with cedar and 
situated in waters lying adjacent to cultivated 
land, buildings, or high eroding banks. 
Biogeographic Sections 
The average distribution of wintering popu- 
lations during 1955-58 is shown in table 55. 
