Red bat ig;1979L west. The National Audubon society collection PR 



distances. During spring and autumn migrations, they 

 are occasionally found clinging to the sides of houses or 

 outbuildings. During a November migration in 1972, a 

 large number of silver-haired bats, apparently con- 

 fused, were killed along with a number of warblers 

 when they flew into Chicago's McCormick Place, just 

 south of Field Museum. 



Cave Bats 

 10 Unlike tree bats, cave bats hibernate during winter in 



caves or other cave-like environments such as aban- 

 doned mines. Cave bats have a hairless uropatagium 

 and rely heavily upon caves for protection from winter 

 temperatures. They are generally much more social 

 than tree bats, often forming groups of thousands. Be- 

 cause they group in such large numbers, in relatively 

 small areas, cave bats are far more vulnerable to human 

 vandalism or natural adverse conditions than are the 

 more solitary tree bats. 



"Clustering" behavior is carried over into the sum- 

 mer when cave bats form maternity colonies, although 



