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



contained these seeds. They were often present in large masses, and 

 together with the seeds of eelgrass formed the bulk of the contents 

 of the stomachs from that region, all of which were taken during the 

 months of October, November, and December. 



musk grass {Char a) and other algae, 3.44 per cent. 



The stomachs of 49 pintails held at least traces of musk grass, 

 and 8 contained other algae. A few were filled with algae alone. 

 The fact that a duck has been feeding upon musk grass often can be 

 detected by the presence of the small, hard reproductive cells 

 (oogonia) which persist in the stomach after all other parts have 

 been digested. 



ARROWHEAD AND WATER PLANTAIN (ALISMACEAe), 2.84 PER CENT. 



Many of the pintails shot on the delta of the Mississippi River, 

 Louisiana, had been feeding on the tubers of an arrowhead (Sagittaria 

 platypliylla) , which is very abundant on the mud flats there. These 

 tubers are known as the "delta potato," and are one of the important 

 duck foods of that region. 11 The seeds of arrowheads occasionally 

 are taken also, as well as the tubers of other species. Seeds of water 

 plantain (Alisma plantago-aquatica et al.) were found in 6 stomachs. 



GOOSEFOOT FAMILY (CHENOPODIACEAE), 2.58 PER CENT. 



Of a series of 35 pintail stomachs collected from a point on the Gulf 

 coast of Texas in October, 33 contained seeds of glasswort (Salicornia 

 ambigua), a low, fleshy, leafless plant growing in dense colonies on 

 mud flats too saline for other vegetation. These seeds amounted to 

 100 per cent of the contents of 25 of the stomachs, and averaged 93 

 per cent in the series of 35. Two of the stomachs contained no 

 fewer than 28,000 seeds each. Five pintails had eaten seeds of 

 pigweed (Chenopodium sp.) and one those of saltbush (Atriplex sp.). 



WATERLELY FAMILY (NYMPHAEACEAE), 2.57 PER CENT. 



The stomachs of 34 pintails contained seeds of water shield (Bra- 

 senia schreberi), 10 the seeds of waterlilies of the genus Castalia, 

 and G those of the genus Nymphaea, which includes the yellow pond- 

 lily. One Florida stomach contained 142 seeds of water shield, 

 4 of a species of Castalia, and the remains of a large number of a 

 species of yellow pondlily. 



DUCKWEEDS (LEMNACEAE), 0.8 PER CENT. 



Only 15 pintails had eaten duckweeds (Lemna sp.). These small 

 plants so relished by the wood duck, form one of the lesser items in the 

 food of the pintail. 



» See Bull. No. 465, U. S. Dept. Agr., pp. 21-24, 1917. 



