32 BULLETIN 862, U. S. DEPARTMENT OF AGRICULTURE. 



Vegetable Food. 



Vegetable matter constitutes about seven-eighths (87.15 per cent) 

 of the total food of the pintail. This is made up of the following 

 items: Pondweeds, 28.04 per cent; sedges, 21.78; grasses, 9.64; 

 smartweeds and docks, 4.74; arrowgrass, 4.52; musk grass and other 

 algae, 3.44; arrowhead and water plantain, 2.84; goosefoot family, 

 2.58; waterlily family, 2.57; duckweeds, 0.8; water milfoils, 0.21; 

 and miscellaneous vegetable food, 5.99 per cent. 



PONDWEEBS (NAIADACEAE), 28.04 PER CENT. 



The pondweed, the family of plants which furnishes the largest item 

 of food for the pintail, is the favorite also of several other species of 

 ducks, including the gadwall and the baldpate. The latter two 

 species, however, partake very largely of the leaves and stems of 

 the plants, while the pintail prefers the seeds. Of the whole number 

 of stomachs of the pintail, 254 contained seeds* or other parts of 

 widgeon grass (JRuppia maritima), at least four of them with from 

 1,000 to 1,300 seeds each. Two others contained about 2,800 seeds 

 each of unidentified species of true pondweed (Potamogeton), and 

 another held over 2,000 seeds of horned pondweed (ZannicheUia 

 palustris). Seeds of sago pondweed (Potamogeton pectinatus), small 

 pondweed (P. pusiUus), leafy pondweed (P. foliosus), and curly 

 pondweed (P. diyersifolius) were identified in a few instances, but 

 pondweed seeds of which the species could not be determined were 

 found in 271 stomachs. Seeds of horned pondweed were present 

 in 18 stomachs, those of bushy pondweed (Najas jlexilis) in 23, while 

 the seeds, and occasionally leaves, of eelgrass (Zostera marina) were 

 found in 93, and amounted to 4.03 per cent of the pintail's total 

 food. This item was most abundant in the stomachs of a series of 

 birds from the southwestern coast of Washington. 



SEDGES (CYPERACEAE), 21.78 PER CENT. 



The seeds of sedges are second only to the pondweeds in importance 

 in the food of the juntai! The plants of this ' family often are 

 semisubmerged, or grow in marshy situations. Probably most of 

 the seeds are taken from the water after they have ripened and 

 fallen, although no doubt a great many are picked from the shorter 

 plants and those which are bent low over the water. Seeds of the 

 .common three-cornered bulrush, or three-square (Scirpus ameri- 

 canus), were identified from 155 of the pintail stomachs, those of 

 prairie bulrush (S. paludosus) from 84, salt-marsh bulrush (S. ro- 

 bustus) from 29, Scirpus cuhensis from 8, river bulrush (S. fluviatilis) 

 from 3, and unidentified bulrushes from 154. Seeds of saw grass 

 (Cladium effusum),- spike rush (EleocJiaris sp.), chufa (Cyperus 

 sp.), beaked rush (RTiynchospora sp.), and sedges of the genera Fim- 



