28 
of them be killed and examined, it will be found in excellent condi- 
tion—in fact, a veritable ball of fat. 
The snowbird (Junco hyemalis) and tree sparrow (Spizella monticola) 
are perhaps the most numerous of all the sparrows. The latter fairly 
swarms all over the Northern States in winter, arriving from the north 
early in October and leaving in April. Examination of many stomachs 
shows that in winter the tree sparrow feeds entirely upon seeds of 
weeds; and probably each bird consumes about one-fourth of an ounce 
aday. In an article contributed to the New York Tribune in 1881 the 
writer estimated the amount of weed seed annually destroyed by these 
birds in the State of Iowa. Upon the basis of one-fourth of an ounce 
of seed eaten daily by each bird, and supposing that the birds averaged 
ten to each square mile, and that they remain in their winter range 
two hundred days, we shall have a total of 1,750,000 pounds, or 875 
tons, of weed seed consumed by this one species in a single season. 
Large as these figures may seem, they certainly fall far short of the 
reality. The estimate of ten birds to a square mile is much within the 
truth, for the tree sparrow is certainty more abundant than this in 
winter in Massachusetts, where the food supply is less than in the 
Western States, and [ have known places in lowa where several thou- 
sand could be seen within the space of a few acres. This estimate, 
moreover, is for a single species, while, as a matter of fact, there are at 
least half a dozen birds (not all sparrows) that habitually feed on these 
seeds during winter. 
Farther south the tree sparrow is replaced in winter by the white- 
throated sparrow, the white-crowned sparrow, the fox sparrow, the song 
sparrow, the field sparrow, and several others; so that all over the 
country there are a vast number of these seed eaters at work during 
the colder months reducing next year’s crop of worse than useless 
plants. 
In treating of the value of birds, it has been customary to consider 
them mainly as insect destroyers; but the foregoing illustration seems 
to show that seed eaters have a useful function, which has never been 
fully appreciated. 
THE ROSE-BREASTED GROSBEAK. 
(Zamelodia ludoviciana.) 
The beautiful rose-breasted grosbeak (fig. 15) breeds in the northern 
half of the United States east of the Missouri River, but spends its 
winters beyond our boundaries. Unfortunately it is not abundant in 
New England, and nowhere as plentiful as it should be. It frequents 
groves and orchards rather than gardens or dooryards, but probably 
the beauty of the male is the greatest obstacle to its increase; the fully 
adult, bird is pure black and white, with a broad patch of brilliant 
rose color upon the breast and under each wing. On account of this 
