90 BIRD FRIENDS 



half of the year they form about four fifths of the 

 food of some sparrows. Most of the work of destroy- 

 ing weed seeds is done between early autumn and 

 late spring. During the summer the birds feed largely 

 on insects. 



Mr. H. W. Henshaw, chief of the Bureau of Bio- 

 logical Survey, estimates that in the year 1906 the 

 weed-seed-eating birds saved to the farmers of the 

 country $35,000,000, on the assumption that the de- 

 struction of these weed seeds resulted in the saving 

 of only one per cent of the crop. 



