FOOD HABITS OF SHOAL-WATER DUCKS. ‘ao 
bristylis and Carex also were taken very frequently by these ducks. 
As many as 1,500 seeds of beaked rush, 3,000 of the three-square, 
3,600 of spike rush, and 9,000 of Scirpus cubensis were counted from 
various single stomachs, while one contained more than 150 of the 
large, horned seeds of beaked rush (Rhynchospora corniculata). 
GRASSES (GRAMINEAE), 9.64 PER CENT. 
Grass remains in the pintail’s food consist also very largely of seeds. 
Many of the stomachs contained the seeds of switchgrass (Panicum 
sp.), barnyard grass or wild millet (Zchinochloa crus-galli), wild rice 
(Zizania palustris), cut grass (Zizamopsis miliacea), salt grass (Dis- 
tichlis spicata), and foxtail (Chaetochloa sp.), often in very large num- 
bers. One was found to contain 11,500 seeds of barnyard grass, 
and another held nearly 4,000 of switchgrass. Included in the grass 
family are cultivated rice (Oryza satwa) and other grains. Rice was — 
found in 52 of the pintail stomachs—24 of them from Texas, 18 from 
Louisiana, and 10 from Florida. Many were crammed with rice 
kernels, and contained nothing else, but all were taken during the 
months of November, December, and February, so there can be no 
doubt that it was all waste grain. Of the other cultivated grains, 
corn was found in 3 stomachs, wheat in 3, barley in 3, and oats in 1. 
This also probably was waste grain, with the exception of oats, 
taken in North Dakota in June, and a few grains of wheat taken in 
Colorado in March. 
SMARTWEEDS AND DOCKS (POLYGONACEAE), 4.74 PER CENT. 
Many of the plants of the family Polygonaceae grow in or near 
water and their seeds are eaten by a great many different kinds of 
birds. The seeds of mild water pepper (Polygonum hydropiperoides), 
found in 29 stomachs, and of water smartweed (P. amphibwum), in 23, 
seem to be the favorites with the pintail. Several also had taken 
seeds of prickly smartweed (P. sagittatum), knotweed (P. aviculare), 
Pennsylvania smartweed (P. pennsylvanicum), water pepper (P. 
hydropiper), and other smartweeds (P. lapathifoluum, P. persicaria, 
and P. opelousanum). About 12,500 seeds of a smartweed, Poly- 
gonum punctatum, were found in the crammed gullet and gizzard 
of one pintail from Alabama. Seeds of dock (Rumezx sp.) were 
present in 7 gizzards. 
ARROW-GRASS (Triglochin maritima), 4.52 PER CENT. 
Arrow-grass is a plant of the marshes, muddy shores, or low 
meadows near salt water. The seeds are borne on erect spikes, and 
are the only parts of the plants commonly eaten by the birds. Eighty- 
eight pintail stomachs, all from the Pacific coast of Washington, 
179375°—20——3 
