THE FINCHES AND SPARROWS. 143 



sparrows, white-throats, song-sparrows, and juncos fairly 

 swarmed during December in the briers of the ditches be- 

 tween the corn-fields. They came into the open fields to 

 feed upon weed seed, and worked hardest where the smart- 

 weed formed a tangle on low ground. Later in the season 

 the place was carefully examined. In one corn-field near a 

 ditch the smartweed formed a thicket over three feet high, 

 and the ground beneath was literally black with seeds. Ex- 

 amination showed that these seeds had been cracked open 

 and the meat removed. In a rectangular space of eighteen 

 square inches were found eleven hundred and thirty half seeds 

 and only two whole seeds. Even as late as May 13 the birds 

 were still feeding on the seeds of these and other weeds 

 in the fields ; in fact, out of a collection of sixteen sparrows, 

 twelve, mainly song, chipping, and field sparrows, had been 

 eating old weed seed. A search was made for seeds of vari- 

 ous weeds, but so thoroughly had the work been done that 

 only half a dozen seeds could be found. The birds had taken 

 practically all the seed that was not covered ; in fact, the song- 

 sparrow and several others scratch up much buried seed." 



This summary of the economic relations of the commoner 

 members of the finch family shows that, on the whole, these 

 birds serve a very useful purpose by destroying the seeds of 

 noxious plants and the lives of injurious insects, but that 

 some species, like the purple finch and pine grosbeak, are 

 occasionally destructive to the buds of fruit-trees. The most 

 striking particulars brought out by a study of their diet are 

 the enormous amount of weed seed taken during winter and 

 the extent to which these so-called seed-eaters take insect 

 food in spring and summer, especially in the presence of an 

 unusual abundance of an edible species. For example, in an 

 orchard infested by canker-worms forty-seven members of 

 this family had eaten ninety-one per cent, of insects and only 

 seven per cent, of seeds, canker-worms alone making forty 

 per cent, of the food. 



