Z LEAFLET 109, U. S. DEPARTMENT OF AGRICULTURE 
On the wing, bats are a match for the swiftest birds of prey, and 
their roosting sites are selected to frustrate enemy attempts to reach 
them. They are not preyed upon to any serious extent by natural 
enemies. Hawks and owls have been observed to wait for and catch 
them as they emerge from their roosts. In season, predatory animals 
sometimes wait patiently beneath bat roosts for the young to lose their 
hold upon their mothers and drop to the ground. Snakes also feed on 
them occasionally, and there is a record of a black snake established 
in the attic of a bat-infested house, where it apparently had fed for an 
extended period on roosting bats taken from between the walls. 
_ Some species of bats are of solitary habits, while others go to the 
social extreme of congregating in colonies ‘numbering millions of 
individuals. The bats that chiefly concern the hosel by choos- 
B38956 
FIGURE 1. eaanee showing typical evidence of bat infestation—the darkened spots Gndicated by 
arrow) made by the bats in going in and out of the openings at the ends of the overlapping siding, under 
the overhang. 
ing available spaces in occupied buildings for their roosting sites 
usually gather in small colonies of a few dozen or a few hundred 
individuals. To be safe from natural enemies, bats ordinarily roost 
in a ‘‘dead”’ space in the upper part of the house, access to which is 
gained through small cracks or other openings. Records in the 
Bureau of Biological Survey indicate that the roosting places are 
found most frequently, in the order named, as follows: In attics, 
between roofs and ceilings, in cornices or other crevices around the 
roof, in walls, in chimneys, behind shutters, around drainpipes, and 
behind rafters and sheathing in open barns. Bats are able to squeeze 
through surprisingly narrow slits or cracks—the smaller species re- 
quiring an opening no wider than three-eighths of an inch. Such 
openings are frequently found in old frame “structures where boards 
shrink or warp or nails become loosened. Another common means 
of ingress into buildings is through openings under the overhang of 
the roof made by overlapping sheathing or drop siding (fig. 1). 
