FOOD BENEFICIAL IN EFFECT ON AGRICULTURE. 



25 



But although sparrows render considerable service by helping to 

 reduce the number of insect pests, by far their most important work 

 consists of the wholesale destruction of the seeds of weeds (see fig. 13). 

 Each fall and winter they flock in myriads to agricultural districts 

 and live on the ripened seeds of weeds. As they attack weeds in 

 their mest critical stage, that of the seed period, it follows that their 

 services must be of enormous practical value. The benefits are 

 greatest in the case of hoed crops, since among these are found the 



largest number of annual weeds, which, 

 being killed b}^ frost, must depend for per- 

 petuation solely upon seeds. The ijrincipal 

 weed seeds prevented by sparrows from 

 germinating are those of ragweed, pigeon- 

 grass, smartweed, purslane, bindweed, crab- 

 grass, lamb's-quarters, chickweed, and ama- 

 ranth (see fig. 14). It is sometimes asserted 

 that no thrift}^ farmer will allow these nox- 

 ious species to ripen seed, but such preven- 

 tion is practically impossible, because even 

 if all the edges of fields and all waste 

 ground could be cleared, weed patches 

 along ditches, roads, and hedgerows would 

 still remain to disseminate seed to culti- 

 vated land. It is in just these places tlmt 

 sparrows congregate in greatest numbers. 

 Some eat more or less weed seed through- 

 out the year, even when insects are most 

 abundant; but their work is chiefl}' from 

 earl}^ autumn until late spring, and is per- 

 haps most noticeable in winter when the 

 ground is white with snow. It is then that 

 the weed patches are all a- twitter with the 

 busy seed-eaters. The birds form ani- 

 mated groups perched on the stalks or 

 darting about on the ground beneath, wind- 

 ing their way in and out among the weeds. 

 So bountiful is the supply, and so eagerly 

 do they avail themselves of it, that the 

 number of seeds consumed by each individual seems beyond the 

 cai)acity of its little body. It is not at all uncommon for a field 

 spari-ow to eat 100 seeds of crab-grass at a single meal. In the stom- 

 acli of a Nuttall's sparrow have been found 300 seeds of amaranth, 

 and in another 300 seeds of lamb's-quarters; a tree sparrow that was 

 examined had consumed 700 seeds of pigeon-grass at a meal, while a 

 snowflake taken at Beaverdam, Wis., which had been breakfasting 

 in a garden in March, had picked up 1,500 seeds of amaranth. 



Fu:. U.— Weed seeds commonly 

 eaten by sparrows: o, bindweed; 

 6, lamb"s-quarters; c. purslane; 

 d, amaranth; e, spotted spurge; 

 /, ragweed; g, pigeon- grass; h, 

 dandelion. 



