28 THE RELATION <>K SPARROWS TO AGRICULTURE. 
fields bo feed on weed seed, and were most active where the smart- 
weed formed a tangle on low ground. Later in the season the place 
was carefully examined. In a cornfield near a ditch the smartweed 
formed a thicket more than :} feel high, and the ground beneath was 
Literally black with seeds. Examination showed that these seeds had 
been cracked open and the meat removed. In a rectangular space of 
is square inches were found L,130 half seeds and only 2 whole seeds. 
During 1 he ensuing season no smartweed grew where the sparrows 
had caused this extensive destruction. Even as late as May 13 the 
birds were still feeding on the seeds of these and other weeds in the 
fields. Sixteen sparrows were collected on that date, and 1 l' of these, 
mainly song, chipping, and field sparrows, proved to have been eating 
old weed seed. So thoroughly had the work been done that diligent 
search showed only half a dozen seeds in the field where they had been 
feeding. The birds had taken practically all that were not covered; 
in fact, the song sparrow and several others had scratched up much 
buried seed. 
In the greater part of the United States most of the song sparrows, 
and all but a very few of the dickcissels and field, chipping, vesper, 
lark, Harris, and grasshopper sparrows, are replaced in winter by 
snowfiakes, juncos, longspurs, fox sparrows, white-throat ed sparrows, 
and white-crowned sparrows. All these birds have much the same 
food habits, but they differ in the quantity and kind of seed they eat. 
Thus, the tree sparrows, or 'winter chippies,' and longspurs feed 
largely on seeds of grasses, especially those of pigeon-grass, crab- 
grass, and allied species, while the white- throated sparrow in the 
Eastern States, Nuttall's sparrow in the Pacific coast region, the 
snowflake of the northern tier of States, and the white-crowned spar- 
row, so abundant in the central part of the United States, part icularly 
relish amaranth and lamb's-quarters. The white-throated sparrow is 
also a great consumer of ragweed, and outranks in this regard every 
other sparrow except the junco. The song sparrow shows a liking 
for polygonums, and in the destruction of the weeds of this genus 
is the most valuable bird whose food habits have thus far been inves- 
tigated. 
During cold weather the native sparrows require an abundance of 
food for warmth, and it is habitual with them to keep their stomachs 
and gullets heaping full — so full, in fact, that if a bird be killed and 
shaken by the feet scores of seeds rattle out on the ground. This 
habit, coupled with their gregariousness, greatly increases their 
efficiency. 
SUMMARY. 
It is hardly to be expected that such seed eaters as sparrows should 
destroy as great a quantity of insect pests as birds that are entirely 
insectivorous. When it is found that in the food of the native spar- 
rows such pesls average but J.") percent, it is only what might be 
