52 
BULLETIN 107, U. S. DEPARTMENT OF AGRICULTURE. 
Stomach analysis of these birds also revealed the fact that the 
value of the young English sparrow as a weevil destroyer varies con- 
siderably and rapidly as his nestling life progresses. From the 
blind, naked, and helpless bird of a day or two, which must neces- 
sarily be feci on the softest and most easily assimilated foods, as 
weevil larvae, caterpillars, spiders, etc., to the lusty-lunged fledgling, 
whose food is characterized by grain and hard-shelled insects, differ- 
ing but little from that of the adult, we find all intermediate stages. 
That some idea may be given of the proportion of the several prin- 
cipal food items found to occur at various stages of the nestling's 
life, the writer has arranged the material into four groups which 
represent as nearly as possible birds of the first, second, third, and 
fourth quarters, respectively, of the nestling life. Six of the prin- 
cipal food items, namely, alfalfa weevils, ground beetles, caterpillars, 
flies, spiders, and grain, are considered iix showing the change of food 
habits as life progresses, and these are illustrated in figure 3. Or- 
thoptera (grasshoppers) form an important article of food late in 
the season and would have been included had field work been con- 
tinued until fall. These insects, especially the nymphs, were eaten 
extensively by nestlings of the first and second quarter during July. 
The following tabulation shows the changing percentages of foods 
during the four quarters of nestling life : 
Quarterly periods. 
Alfalfa 
weevils. 
Ground 
beetles. 
Caterpil- 
lars. 
Flies. 
Spiders. 
Grain. 
Miscella- 
neous. 
First quarter . . 
Second quarter 
Third quarter . 
Fourth quarter 
37.95 
29.87 
26.05 
18.75 
2.55 
5.11 
6.23 
7.43 
26.65 
16.09 
4.72 
3.12 
6.71 
4.01 
2.55 
.62 
6.43 
1.99 
.35 
5.28 
31.69 
49.25 
63.18 
14.43 
11.24 
10.51 
6.55 
As the bird becomes older there is a gradual decrease in the con- 
sumption of weevils, as well as of other soft and easily digested foods, 
as caterpillars, flies, and spiders, while the hard-shelled ground beetles 
are taken in greater quantity. Grain, mostly wheat, early becomes 
an important food item, and by the time the bird has left the nest it 
is well fitted to uphold the reputation of its parents. 
FIELD OBSERVATIONS ON THE FEEDING OF NESTLINGS. 
Observations also were made of the amount of food given the 
young English sparrows and the frequency of the feedings. Parent 
birds were timed for a period, usually an hour, and at the end of this 
time the incoming bird was captured and the contents of its bill and 
throat recorded. By taking the average of a number of such obser- 
vations the writer was able to get a fair idea of the amount of food 
consumed daily by a nest of these young birds. 
