54 BULLETIN 107, TJ. s. DEPARTMENT OF AGRICULTURE. 
Another series of observations gave an average of 5 minutes 
between the feedings. The female in this case carried a ground 
beetle (Harpalus amputatus), a caterpillar, and 9 larvae of the 
alfalfa weevil in her bill and throat. 
Observations of feeding of nestlings on an unoccupied farm showed 
that visits were made at the rate of 17 trips an hour, or about one 
trip every 3J minutes. The female was carrying 28 larvae of the 
weevil on her last trip. 
From this series of five observations it appears that the parent 
English sparrows visited their nest on an average of about once 
every 5^ minutes, or a little more than 11 trips an hour. The four 
adults captured had as food for their young 2 kernels of wheat; 
IT alfalfa weevil larva? ; 1 ground beetle, 9 weevil larvae and a cater- 
pillar ; and 28 weevil larvae, respectively. Three other adults taken 
in the fields had food for nestlings in their bills. This amounted to 
18 weevil larvae and an aphid in the first, 5 larvae in the second, and 
3 cocclnellid larvae, 13 weevil larvae, and 2 pupae in the third. 
Though this is a rather heterogeneous assortment, it would appear 
that 15 larvae of the weevil or their equivalent in bulk of other insects 
would be a fair estimate of an average amount of food brought in at 
each trip by adult birds. In fact, it is certain that the material 
brought in frequently greatly exceeded this amount. 
Allowing, then, 15 larvae at each trip and 11 trips per hour, these 
birds would bring in 165 larvae per hour. Then, assuming that the 
young were being fed for 12 hours each day, a conservative estimate, 
we would have a total of 1,980 larvae consumed by one brood in one 
day. As previously stated, straw- thatched sheds containing upward 
of 100 nest holes, both old and new, are frequent, and it is not uncom- 
mon to find farmyards where this number of nests are occupied. 
There are also ample nesting sites about the other buildings and in 
the ever-present Lombardy poplar, cottonwood, or box elder. Such 
a colony of birds would devour a daily total of 198.000 larvae, or an 
equivalent bulk in other food. As the young birds remain in the nest 
for at least 10 days and are probably fed several days longer by the 
adults, they will have eaten food equivalent to the bulk of 1,980,000 
larvae during their nestling life. 
As these birds are not feeding exclusively on this insect, the aver- 
age amount of weevils eaten by young English sparrows during the 
height of the season being about 25 per cent of their food, under 
average conditions we would have the young of such a colony eating 
495.000 weevils. TThile there may be some farms where only com- 
paratively few larvae are eaten, there must be others where favorable 
circumstances will bring the total destroyed by the nestlings of one 
brood nearer the larger figure. 
