ELIMINATING BATS FROM BUILDINGS 5 
THE POPULAR objections to the presence of bats may be lessened to 
some extent when it is more generally appreciated that they are not 
only harmless but useful as well. Their food consists 
Economic entirely of night-flying insects, which are taken on the 
Status wing, and the majority of these are economically injuri- 
ous. Alargeproportionof the food of many species con- 
sists of mosquitoes, and batshave beencredited also with material assist- 
ance in the control of codling moths and other horticultural insect pests. 
The droppings of bats, known in commerce as guano, are rich in 
nitrogen and phosphoric acid and have a relatively high value, but 
there is now little commercial demand for the product. The guano 
of some of the larger bat caves of 
the Southern States has yielded to 
their owners an income of several 
thousand dollars. The usefulness 
of bats through their activities as 
insect destroyers and the value of 
their guano have led to several 
attempts, largely unsuccessful, to 
encourage the colonization of some 
species (especially the Mexican free- 
tailed bat, Tadarida mexicana), by 
building large, artificial roosts for 
them in areas where malarial mos- 
quitoes are prevalent (fig. 2). 
The objection to the presence of 
bats is partly due to the aversion 
that many people have to them 
similar to that they have to rats, 
spiders, and snakes, but complaints 
are usually based on the highly 
objectionable odor that is always 
associated with an established bat 
roost. The characteristic pungent 
and penetrating odor comes from 
the droppings and urine, which 
rapidly collect under their roosts. 
Another less important objection . : 
arises from the scratchy, scram- B237.M 
bling noises made by the bats as Ficure 2.—Artificial bat roost erected near San 
a make the ey through double ata cost of $2,000 Uo trae Max iban fon teilea 
walls in crawling: from the entrance ats as a Means of mosquito control. It has 
Holes fo the! final toosting: spote, Same eRgeuaed. bats mara aken ap thet 
As this sleep-dispelling noise occurs 9 “""* %0™ Flotida to Texas. 
just at dawn, objection is especially justifiable if the roosting place 
adjoins a bedroom. In general, the elimination of bat roosts from 
dwellings is necessary. 
As Bats individually are almost wholly beneficial, and at a distance 
are In no way objectionable, they should not be destroyed except as 
alast resort. It is only the bat roosts that have been 
Bat Control established in occupied buildings that should be 
eliminated. This can usually be. accomplished in 
either of two ways: (1) Excluding the bats by closing the openings 
through which they gain entrance; and (2) evicting them by treating 
