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HABITS 
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Some bats migrate freely and make their seesonal abode in the locality c 
most attractive food supply. Others apparently inhabit the same roost the yeer 
round, hibernating there during the colder months. They have been found hibernat- 
ing in temperatures of 25°F, below zero and have been reported as active during . 
midwinter im many northern States as a result of incomplete or arrested hiberna— 
tion in heated houses. While resting or in hibernation they ncrmally heng head 
downwerd, suspended by the curved rigid claws of the hind feet. 
Bats provide no nest of any kind. The 1 or 2 young {rarely mcre).cling to 
the mother until old enough to shift for themselves. 
Bats are not preyed unon to any serious extent by natural enemies. Hawks 
and owls have been observed to 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 4 
feed on them occasionall;, anc 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 bets taken from between the walis. | 
Some species of bats are of solitary habits, while cthers go to the social 
extreme of congregating in colonies numbering millions of individuals. The bats 
that chiefly concern the householder by choosing available spaces in occupied 
buildings for their roosting sites usually gather in small colonies of a few dozen 
te a few hundred individuals, Bats ordinarily roost in an unused space in the 
upper part of the house, access to which is gained through small cracks or other 
openings. Records in the Fish and Wildlife Service indicate that the roosting 
places most frequently selected are, inthe order named: In attics, between roofs 
and ceilings, in cornices or other crevices around the roof, in walls, in chimneys, 
behind shutters, around drain pipes, and behind rafters and sheathing in open barns. 
Bats are able to squeeze through surprisingly narrow slits or cracks — the smaller 
species requiring an opening no wider than three-eighths of an inch. Such open— 
ings are frequently found in old frame structures where boards have shrunk or have 
become warped or nails have loosened. Another common means of ingress inte build 
ings is through openings under the overhang of the roof made by overlapping sheath— 
ing or drop siding. 
ECONOMIC STATUS 
Popular objections to the preserice of bats might be lessened to some extent 
if it were more generally appreciated that these animals are not only harmless but — 
useful as well. Their food consists entirely of insects, which are taken on the © 
wing, and the majority of these are economically injurious. Part of the food of 
some species consists of mosquitoes; bats have been credited also with materially 
assisting in the contxol of codling mcths and other horticultural insect pestse $ 
The croppings 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 commer 4 
cial demand for the product. The guano in some of the larger bat caves of the 
Southern States, however, has yielded to their owmers an increase of several thou- : 
sand dollars. The usefulness of bats through their activities as insect destroy— 
ers and the value of their guano have led to several attempts, largely unsuccess-  — 
ful, to encourage the colonization of some species (especially the Mexican free— ‘ 
tailed bat, Tadarida mexicana) by building large, artificial roosts for them in ~ 
areas in which malariel mosquitoes are prevalent. 2 
2 
