30 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY. 
FOOD OF YOUNG. 
Among the stomachs examined were those of 22 nestlings, varying 
in age from 2 days to those just ready to leave the nest. They were 
taken from May 30 to July 2. inclusive. In order to ascertain if im- 
portant differences exist between the food of the adults and that of the 
young, the contents of these stomachs were tabulated separately. 
Comparison shows little or no difference in the quantity of vegetable 
matter eaten by adults and young. 
The animal matter in the food of the young is precisely of the 
same kind as eaten by adults, but the proportions are rather differ- 
ent. Hymenoptera are the largest item in the food of the young 
as well as of the parent birds, and amount to 42 percent for 
the former against 39 percent for the latter. Diptera stand next in 
importance, with 30 percent for the young against 12 percent for the 
adults. As these insects are mostly soft-bodied, it is the usual custom 
of birds to feed a greater proportion of them to the young. Hemip- 
tera amount to a little more than 16 percent of the nestlings’ food, 
while the adults eat them to the extent of nearly 27 percent. Beetles 
are fed to the young to the amount of about 10 percent, while the 
parents eat them to the extent of 19 percent. This again might 
naturally be expected, as most beetles are hard and less easily 
digested than flies and some other insects, and hence are less suitable 
food for young birds. 
From the foregoing it is evident that the food of young cliff 
swallows does not differ in kind from that of the adults, but is dis- 
tributed among the various orders of insects in somewhat different 
proportions. Hymenoptera and Diptera constitute nearly three- 
fourths of the dict, evidently because they are soft and easily broken 
up and digested. Beetles and bugs appear in the stomachs less 
frequently. While beetles are not extensively eaten, it is worthy of 
note that the variety is considerable, as representatives of no fewer 
than 10 species were contained in the stomach of one nestling. One 
stomach held a few bits of eggshell, and gravel was identified in 
two others. One of these contained 7 good sized gravel stones; the 
other, pieces of glass aml gravel. The supposed function of gravel 
in the stomachs of birds is to assist in breaking up the food. That 
gravel should be given young cliff swallows when not taken by the 
adults is remarkable. The feeding of gravel to the young has been 
noted in the case of other species of swallows. 
WESTERN BARN SWALLOW. 
(Hirundo erythroqastra.) 
The barn swallow is rapidly learning, not only that the structures 
built by man afford excellent nesting sites, but that the presence of 
