Birds as Destroyers and Distributers of Weed Seeds. 71 



CHAPTER VI. 



BIRDS AS DESTROYERS AND DISTRIBUTERS OF WEED SEEDS. 



" The problem of weed destruction is perennial in every land 

 where agriculture is practised. Indeed, so serious is it, that soil 

 culture may be said to be an everlasting war against weeds." 



SYLVESTER D. JUDD (72, p. 221), 

 1. Destruction of Weed Seeds. 



No one will deny that birds annually destroy a large quantity 

 of the seeds of various weeds. The inspection of an acre of truck 

 land in the autumn is recorded by Judd (68, p. 78) as giving some 

 idea of the work of weed-destroying birds. "Crab-grass and 

 pigeon-grass formed a low undergrowth, while lamb's-quarters, 

 pigweed, and giant ragweed from 6 to 10 feet high rose in a thick 

 weed forest. A flock of fifteen quail foraged in the centre of the 

 area, twenty-five doves were scattered over the upper end, and 

 fully two hundred native sparrows scurried about at the lower end, 

 while a band of three hundred goldfinches clung to the ragweed 

 stalks plucking off seeds. 



"If we make the fair assumption that the birds remained on 

 this acre of plenty long enough to obtain a full meal, we can 

 reckon approximately the destruction wrought. At a moderate 

 estimate twenty seeds apiece may be allowed for the goldfinches, 

 one hundred for the sparrows, provided that they were from crab- 

 grass or pigeon-grass, and five hundred for the doves and bob- 

 whites, or a total of 46,000 seeds destroyed at a single breakfast." 



Writing of the bobwhite, the same author refers to three 

 coveys of these birds. In the first covey one bird was shot, seven 

 from the second, and five from the third. The stomach contents 

 were examined and showed that these thirteen birds had taken 

 weed seed to the extent of 63 per cent, of their food. Thirty-eight 

 per cent, consisted of ragweed, two per cent, of tick-trefoil, part- 

 ridge pea, and locust seeds, and twenty-three per cent, of miscel- 

 laneous weed seeds. Although the stomachs and crops were not 

 well filled, the birds had eaten 5,582 weed seeds. 



In another case (p. 25) Judd records the finding of three 

 hundred seeds of amaranth in the stomach of one Nuttall's 

 sparrow, and three hundred seeds of lamb's-quarters in a second; 

 in a tree sparrow seven hundred seeds of pigeon-grass were found, 

 and in a snowflake (Passerina nivalis) were 1,500 seeds of amaranth. 



