FOOD HABITS OP MALLAED DUCKS. 



17 



Table I. — Items of vegetable food identified in stomachs of mallard ducks and the number 

 in ivhich found — Continued. 



Kind of food. 



Common 

 mallard. 



Black 

 duck. 



Southern 

 black 

 duck. 



Total number of stomachs examined 



SUBKINGDOM SPERMATOPHYTA— Continued. 



Potamotegonaceas . 



Potamogeton lucens (shining pondweed ) 



Potamogeton prxlongus (white-stemmed pondweed) 



Potamogeton foliosus (leafy pondweed) 



Potamogeton friesii (Fries pondweed) 



Potamogeton pusillus (small pondweed) 



Potamogeton pectinatiis (sago pondweed) . '. 



Potamogeton perfoliatus (redhead grass) 



Potamogeton sp. (unidentified pondweed) — 



Ruppia maritima (widgeon-grass) ■- 



Zannichellia palustris (horned pondweed) 



Zostera marina (eelgrass) 



NaiadaceEe. 



Naias flexilis (bushy pondweed) 



Juncaginacese. 



Triglochin maritima (arrow-grass) 



lUismacese. 



EcMnodorus sp. (burhead) 



Alisma plantago-aquatica (water plantain) 



Alisma sp. (water plantain) 



Sagittaria platyphylla (delta potato) 



Sagittaria latifolia (wapato) 



Sagittaria teres (goose-grass) 



Sagittaria graminea? (grass-leaved wapato) 



Sagittaria sp. (arrowhead) . ? 



Damasonium californicum ; 



Hydrocharitacess. 



Philotria canadensis (waterweed) _. 



ValUsneria spiralis (^vild celery) 



Limnobium spongia (frogbit) 



Graminese. 



Unidentified grasses 



Zea mays (Indian corn) 



Sorghum sp 



Paspalum distichum i 



Paspalum sp 



EcMnochloa crus-galli (wUd millet) 



Panicum sp. (switch grass) 



Panicum dichotomiflorum (switch grass) 



Chsetochloa lutescens (yellow foxtail) 



ChsetocMoa sp. (foxtail grass) 



Cenchrus sp. (burgrass) 



Zizaniopsis miliacea (cut grass) 



Zizania aquatica (wild rice) 



Homalocenchrus oryzoides (rice cut grass) 



Homalocenchrus lenticularis (catch-fly grass) 



Homalocenchrus virginicus (false rice) 



Homalocenchrus sp. (unidentified cur grass) 



1,725 



431 



85 

 10 

 4 



75 



7 



1 

 3 

 3 



89 

 2 



23 

 2 



2 

 38 

 135 



74 

 14 



622 



19 



1 



217 



101 



2 



71 



8 Paspctlum boscianum and Eriochloa punctata also have been identified from a common mallard's stomach 

 by L. K. Dewey. 



64336°— 18— Bull. 720 3 



