22 THE -RELATION OF SPARROWS TO AGRICULTURE. 



the roasting-ear stage, and feed on it from the time it is put in the 

 crib until wheat comes in the milk again in June. There is scarcely 

 a grain that they do not injure, while with the native sparrows the 

 reverse seems to be true. The latter eat a little grain, but seldom 

 does it amount to more than 5 percent of the year's food, a modest 

 fee for their service when it is considered that the meadowlark, one 

 of the best birds of the farm, takes 13 percent of its food in grain, 

 the crow 35 percent, and the crow blackbird 47 percent. 



The most serious charge that can be brought against sparrows is 

 that they distribute noxious plants, the seeds of which pass through 

 their stomachs and germinate when voided from the body; and 

 this, though not stricth^ germane to the subject under considera- 

 tion, will be treated of here as the most appropriate place. Spar- 

 rows do not distribute catbrier, poison sumach, and poison ivj, as 

 do man}' birds, but it is probable that they do, to a certain extent, 

 disperse the seeds of such weeds as amaranth, gromwell, and spurge. 

 However, it seems likelj^ that this agency of seeding down farms to 

 weeds is infinitesimal when compared with the dispersion of weeds 

 caused by the use of manure containing weed seed and the plant- 

 ing of impure seed, which often contains seeds of foreign weeds 

 of the worst stamp. The digestive apparatus of sparrows has the 

 power to crack or crush the seeds of crab-grass, pigeon-grass, pig- 

 weed, lamb's-quarters, and most other seeds, including the hard 

 drupes of the blackberrj^. I have examined thousands of stomachs 

 of sparrows containing ragweed, and have never found an unbroken 

 seed. The outer ribbed shell of the akene is cracked and not 

 swallowed, but parts of the true seed coat in the shape of angular 

 fragments 3 to 5 mm. long, which are dirty gray externall}^ and green- 

 ish white internally, are usuallj^ found during stomach examination. 

 Uncrushed cotyledons are seldom met with. These facts, which 

 hold also when seeds of wild sunflowers and polj^gonums are eaten, 

 seem to preclude the possibilitj^ of subsequent germination. Con- 

 cerning the likelihood of the germination of the seeds of weeds that 

 are grasses it may be stated that time and again tree sparrows 

 which have fed on pigeon-grass have been examined, and it has been 

 found that while their gullets contained from 100 to 300 whole pigeon- 

 grass seeds with the inner glumes removed, the gizzards were filled 

 with a pasty mass of endosperm containing not more than a dozen 

 whole seeds. But with the harder, smaller seeds the possibility of 

 germination is better. The digestive organs, although they have the 

 power of cracking such seeds, nevertheless occasionally allow some to 

 pass out in a perfect condition, as was shown by an experiment Avith 

 a captive song sparrow in which amaranth seeds were voided unin- 

 jured and germinated very well. Birds take seeds for food, however, 

 and it seems probable that such use would preclude the evacuation of 

 any but a most insignificant proportion of uninjured seeds. 



