136 BIRDS IN THEIR RELATIONS TO MAN. 



uncovered, and for that reason comparatively few birds remain 

 there during the hardest part of the winter. A little farther 

 south they are very abundant in cold weather, and the amount 

 of seed they consume is wellnigh incredible. 



Professor Beal 1 has estimated that during the two hundred 

 days they average to remain in the State of Iowa, reckoning 

 ten sparrows to the square mile and one-fourth of an ounce 

 as the daily ration, eight hundred and seventy-five tons of 

 weed seed are eaten by this species alone. The only 

 complaint to be entered against it is that sometimes it eats 

 the seeds of cultivated millet left exposed in shocks out-of- 

 doors. 



The White-crowned and the White-throated Sparrows 

 have much the same feeding habits as the tree-sparrow. The 

 seeds of ragweed and the various sorts of smartweed, knot- 

 weed, and bindweed form a chief part of their winter food. 

 About three-fourths of the food of both species consists of 

 vegetable matter, the rest being insects and allied forms. 

 These two species differ from most of the other sparrows in 

 that they take very few grasshoppers and comparatively little 

 grass-seed, while on the other hand they take a small per- 

 centage of wild fruit. 



The Pacific coast form of the white-crowned sparrow — 

 sometimes called Nuttall's sparrow — has been carefully 

 studied by Dr. T. S. Palmer. Unlike most of the native 

 sparrows, this subspecies is sometimes injurious through its 

 destruction of grain in newly sown fields or that ready to 

 harvest. As a partial compensation, however, theee birds 

 eat great quantities of weed seeds. 



The Field-Sparrow is an abundant and widely distributed 

 species, occurring in summer in southern Canada and the 

 Northern States and in winter in the Southern States. Its 

 food is approximately forty per cent, animal and sixty per 



1 See Some Common Birds in their Relation to Agriculture, p. 28. 



