10 EOBNED LABE8 IX RELATION TO AGRICULTURE. 
monthly average, and it is consumed by the adults alone. This result 
is in harmony with the observed fact that the breeding season taxes 
the strength of birds, and hence an easily assimilated, highly nutri- 
tious food is required. 
In May there is a further increase in the amount of animal food 
eaten, the maximum (43.4 percent) for the year being reached. The 
percentage is higher in this month because there are included in the 
computations several nestlings, which were [\'d almost exclusively 
upon insects. However, the adults also consume more animal food 
at this time, and the adolescent birds, while they do not eat as large 
an amount as their parents, have not developed the strong vegetarian 
taste which characterizes them later. The principal elements of the 
animal food in May are weevils. May beetles (insects more commonly 
known as June bugs), caterpillars, and grasshoppers. In June the 
amount of insects eaten becomes smaller. The former nestlings, now 
independent of the old birds, are largely vegetarian, and counteract 
the influence of the adults, which are even more insectivorous in 
this month than in May. More weevils, leaf beetles, and ants are 
eaten in June than in May. but fewer May beetles, caterpillars, and 
grasshoppers. 
From May to August the proportion of animal food would proba- 
bly be about the same in each month were it not for the peculiar diet 
of the young birds. The consumption of the maximum number of 
insects in May is the result of the influence of the nestlings and 
adolescent larks. The former, being highly insectivorous, raise the 
percentage in May, while the adolescent birds, because of the oppo- 
site trait, tend to lower the percentage in June, duly, and August. 
When the diet of the adults alone is considered, the proportion of 
animal food for the latter part of the summer increases, and the maxi- 
mum comes, as in tin 1 case of a great many other species, in August. 
(See fig. 2.) Two factors tend to raise the percentage of animal food 
in this month- -first, the molt, which in many cases is known to 
create a ravenous appetite for such food, and, second, the great abun- 
dance of insects, particularly grasshoppers, these in August forming 
the bulk of the animal food of many species of birds. Although 
horned larks eat a considerable number of grasshoppers, they con- 
sume a greater number of weevils than of any other insects. These 
small, inconspicuously colored insects, most of which are actual or 
incipient pests of the worst kind, constitute nearly IS percent of 
the food ill August. Afler this month the amount of animal food 
decreases rapidly. Caterpillars, grasshoppers, beetle larvae, scara- 
beeid and carabid beetles are soon entirely lacking. The lowest point 
in the entire year for the consumption of animal food is reached in 
December, when only 1 percent is obtained. During the winter 
