. Bulletin - Biological Survey. Zoology, Economic. SEEDS EATEN BY GRAY GROSBEAK. 29 WEEDS. Grass seeds constitute an average of percent of the total food of the birds examined, or more than five-sevenths of the vegetable food alone. Most important among them are foxtail (Chcetocholoa, fig. 17) and bur grass (Cenchrus, Plate II, fig. 10), which together amount to percent of all the bird's food. Since these grasses are among the most pernicious weeds, the parrot-bill is more than welcome to all of their seeds it desires. The seeds of other grasses also are im- portant, furnishing
. Bulletin - Biological Survey. Zoology, Economic. SEEDS EATEN BY GRAY GROSBEAK. 29 WEEDS. Grass seeds constitute an average of percent of the total food of the birds examined, or more than five-sevenths of the vegetable food alone. Most important among them are foxtail (Chcetocholoa, fig. 17) and bur grass (Cenchrus, Plate II, fig. 10), which together amount to percent of all the bird's food. Since these grasses are among the most pernicious weeds, the parrot-bill is more than welcome to all of their seeds it desires. The seeds of other grasses also are im- portant, furnishing percent of the bird's subsistence. Among them are seeds of witch and crab grasses, most species of which are weeds. Yard or wire grass {Eleusine indica) also is eaten. Seeds of a spurge {Croton sp.) contribute percent. to this grosbeak's fare, and other weeds, in- Fig. 17.—Seeds of yellow fox- tail (Chwtochloa glauca). (From Hillman, Nevada Ex- periment Station.) eluding bindweed (fig. 21), lambs' quarters, tumbleweed (fig. 18), sunflower, carpet weed, nightshade, vervain (fig. 3), mallow, etc., compose percent. Thus the gray grosbeak is a great consumer of weed seeds, and it is remarkable that seeds form practically seven-tenths of the food in August and September, when insects are superabundant. The bird's habit of feeding upon weeds is undoubtedly beneficial, especially be- cause it eats so many seeds of foxtail and bur grass, pests with which every farmer in the South has to contend. GRAIN. The only grain found in stomachs of this species is sorghum. Six birds had eaten it in quantity sufficient to make an average of percent of the total food. Ignoring even the fact that sorghum is • d Fig. 18. -Seeds of rough tumbleweed (Amaranthus retroflexus). Experiment Station.) • • (From Hillman, Nevad? usually grown for fodder, not for grain, the amount consumed is so small that there need be no fear of damage by this shy and uncom- mon bird. Animal Food. Whi
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