11 THE RELATION OF SPARROWS TO AGRICULTURE. 
fact thai giant ragweed seeds are rarely met with in sparrows' stom- 
achs in a condition allowing identification. 
The grain of spreading panicnm, being inclosed in sheaths, rattles 
oiii on the ground a Little at a time throughout the winter, and thus 
affords several species of sparrows a constant supply of food. I fader 
some of these plants where a son- sparrow had been hopping about 
were found 12 -rains. 6 of which proved to be empty, and under 
others where a junco had been picking from the ground 5 out of 6 
grains found were empty. Sparrows appear to make a practice of 
removing the outer glumes of these grains before swallowing them, 
while those of the closely related crab-grass they seldom, [f ever, 
remove. 
CI im bin- false buckwheat rains down multitudes of its seeds, which 
furnish an abundant and accessible supply of food. In one sandy 
place thick with birds' tracks 52 of the seeds were found within a 
radius of i } feet, and all but 5 were empty. Seeds of this plant are 
shiny black and look like miniature beechnuts. In some cases one 
of the three sides of the sa^\ had been cut away, while in a much 
greater number one of the three edges had been slit so as to leave 
the empty seed shell entire and apparently uninjured. 
Part of the investigation on tins farm Mas directed to the ques- 
tion of the dissemination of weed seeds by sparrows. One hundred and* 
fifty bird droppings were collected on each side of the brook, in the 
ragweed field and in the weedy garden above. Examination of these 
revealed but 7 uninjured seeds, one of crab-grass and 6 of amaranth, 
certainly a very insignificant proportion of the number consumed. 
And H is not unlikely that many of those thus voided uninjured are 
afterwards taken a second time. Most of the dung consisted of the 
pulverized remains of seeds, among which the most conspicuous were 
small fragments ol the akenes of ragweed. The finely comminuted 
fragments of grass seeds were also very abundant. Among these 
crab-grass occurred often, but tin- remains of pigeon-grass and spread- 
ing panicum were positively identified in only a few instances, proba- 
bly because these two seeds are usually hulled before they are 
swallowed (see p. I' 1 )- Amaranth and Lamb's-quarters were easily 
recognized by the characteristic texture of the coats of their seeds, 
and in one instance by the empty half shells of t he seed. Kits of the 
shiny seeds of climbing false buckwheat frequently appeared in the 
dung. The seeds of sedge and oxalis were comparatively rare. 
Winter observations on the District of Columbia farm brought 
out several points which ii is to be hoped may prove to be general. 
1'nder favorable conditions the entire farm was worked over thor- 
oughly, even at a season when birds require more or less accessible 
cover for protection. The sparrows took theirfood chiefly from the 
ground, in contrast t«> other species, which they thus supplement. 
They appeared to have manipulated a large portion of the seeds left 
