450 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. 



Where the birds of the field are undisturbed they tend to hold the 

 grass insects in check. On the other hand, when the numbers of 

 birds in the field are for any reason insufficient, the insects increase. 



Here is an instance of this : Some years ago in Bridgewater, Mass., 

 a great battue was held by the ignorant townspeople in the spring of 

 the year, and so many field birds were killed that their dead bodies 

 were plowed into the land for manure. The following summer 

 whole fields of grass withered away and died. This was due solely 

 to the fact that the number of field birds had been reduced, and in 

 consequence the pressure which nature demands the field birds shall 

 exert upon the field insect had been released. 



Again, at one time in New Zealand it was no uncommon thing to 

 see English grass wither up in large patches, as though scorched by 

 fire. This was due to the work of a crane fly and click beetle, the 

 larvse of both of which were addicted to the habit of eating the roots 

 of the grass, just under the surface. English grass was then com- 

 paratively limited in the up-country districts, and, as there are large 

 tracts of land in New Zealand destitute of native grasses, the depre- 

 dations of these insects became a serious matter to those settlers who 

 had stock to feed and who were relying on the English grass to feed 

 it. It was all the more serious because the insects were without any 

 natural check, the native birds which had kept them in subjection 

 before the advent of the white man having been either killed or 

 driven from the vicinity of the homesteads. So the beetles continued 

 to make merry, to marry, and to multiply. In a corresponding ratio 

 the grass continued to fade, to wither, and to die. 



Then came the English starling, and so voraciously did it feed on 

 the larvse that soon all was green again. 



A case similar to the foregoing occurred about five years ago in 

 an inland district of Australia, where, owing to the ruthless destruc- 

 tion of wild bird life, grubs took possession of the land, and, eating 

 out the grass by the roots, transformed what had been a rich pas- 

 tural country into an unprofitable waste. 



Without the aid of birds grass could not be grown. The grub of 

 a single species of beetle, if unchecked in its multiplication^ could 

 destroy all the roots in our meadows ; or any one of the several spe- 

 cies of cutworms, if its reproduction was not restrained by birds, 

 might be sufficient to destroy all the verdure above ground. 



HAWKS AND OWLS. 



The injury to trees, crops, and grass by insects is not the only evil 

 that threatens man as a sequence to the destruction of birds. Rapa- 

 cious birds hold a chief place among the forces which are appointed 

 to hold in check small rodents, which breed rapidly, and unless kept 

 within bounds are exceedingly destructive. Yet, notwithstanding 



