Table 57 
FOODS OF 40 BLACK DUCKS FROM BRACKISH ESTUARINE BAYS WITH ADJOINING AGRICULTURAL FIELDS? 


Leaves, Stems and Rootstalks of Animal Food U5% (29-62) 
Submerged Aquatic Plants 15% (58-88) 
Macoma balthica (Pelecypoda) 32 (18-50 
Claspingleaf Pondweed 50 (33-67) 
Brachidontes recurvus (Pelecypoda) 8 ( 1-21) 
Eelgrass 2 (26-59) 
Gemma, gemma (Pelecypoda) S ( +-17) 
Widgeongrass 28 (1h-bhh) 
Volsella demissa (Pelecypoda) 2 ( +=1)) 
Sago Pondweed 2 ( +-1h) 
Mytilidae (sp. 7) 2 ( +-1)) 
Seeds ; 60 (3-76) 
Melampus bidentatus (Gastropoda) 2 ( +-1h) 
Widgeongrass 42 (26-59) 
Undetermined Mollusks 2 ( +-1)) 
Claspingleaf Pondweed 28 (1b-L) 
Xanthidae 2 ( +=1)) 
Saltgrass 5 ( +17) 
Gammaridae 2 ( +-1h) 
Olney Three-square 2 ( +=1h) 
Erichsonella sp. (Isopoda) 2 ( +-1k) 
Saltmarsh Bulrush 2 ( +-1h) 
Molgula sp. (Tunicata) 2 ( +-1h) 
Hi ghtide-bush 2 ( +1) 
Fish 2 ( +-1h) 
Undetermined Species 8 ( 1-21) 
Grain 25 (12-h2) 
Com 25 (12-2) 
1 Chester River, Eastern Bay, and Choptank River Sections. All collected during late fall and winter. 
Percentage occurrence of foods that made up 5% or more of the volume in individual birds. Figures in 
parentheses show 95% confidence limits. 
Table 58 
FOODS OF 8 BLACK DUCKS FROM FRESH ESTUARINE BAY MARSHES IN DORCHESTER COUNTY? 
Seeds 88% (47-100) Rootstalkes of Emergent 
Aen 38 ( 876) Marsh Plants 12% ( +-53) 
Olney Three-square 25 ( 3-66) Grass (Gramineae) 12 ( +-53) 
Common Three-square 12 ( +-53) Animal Food 62_ (2h-92) 
Bulrush 12 ( +=53) 
Rice Cutgrass 12 ( +453) Fish (chiefly, Poecilidse) 25 ( 3-66) 
Widgeongrass 12 ( +-53) Mulinia lateralis (Pelecypoda) 12 ( +-53) 
Smar tweed 12 ( +=53) Mytilidae 12 ( +253) 
Leaves, Stems and Rootstalks 
of Submerged Aquatic Plants 38_ ( 8-76) Decapoda 12 ( +-53) 
sn i 12 ( +53) Chironomidae: larvae 12 ( +53) 
Claspingleaf Pondweed 12 ( +453) 
Pondueed 12 ( +453) Belostomatidae 12 ( +-53) 

1 Collected during fall, winter and early spring. Percentage occurrence of foods that made up 5% or more 
of the volume in individual birds. Figures in parentheses show 95% confidence limits. 
124 
