BATS IX RELATION TO GUANO AXD INSECTS 5 



the town, practically all headed in one direction. They fly several 

 hundred feet above the ground, on their way from their roost to 

 favorite hunting grounds, often in the vicinity of water. 



Bats often come into open rooms while seeking their prey and 

 flv about with great skill, avoiding all objects and feasting on such 

 insects as also enter through the open doors or windows, alighting 

 for a moment on the walls or moldings to rest or devour a moth, 

 but always careful to keep out of reach of human occupants. All of 

 our native bats are absolutely harmless. The fear which they 

 sometimes inspire is wholly baseless and has its origin in fictitious 

 stories told to children and passed on from generation to generation. 



At early dawn the bats return to their regular sleeping places in 

 caves, dark rooms, under tiles or other openings in roofs, in holes 

 and crevices among rocks, or in hollow walls of buildings. They 

 are usually suspended by their sharp, curved hind claws and sleep 

 until the next evening, where conditions for such a position are 

 favorable. In other places they may be found packed in deep 

 crevices, frequently too narrow even to admit the hand. In the 

 roofs of small caves in the rockhills near the suburbs of Mexico City 

 there are many bats in crevices of this kind. They commonly take 

 possession of deserted attics and similar places in old churches or 

 other buildings and in deserted storerooms. 



Mexican free-tailed bats, like many others, have the habit of 

 hanging up part of the night in convenient places near their roosts, 

 a- under the roofs of verandas or similar shelter, and the floor 

 beneath is covered each morning with many scattered pellets of ex- 

 crement. 



Exceedingly gregarious, these bats sleep in large numbers closely 

 packed, sometimes hundreds, or even thousands, in a solid mass, 

 clinging to one another in such density that it is difficult to under- 

 stand how those in the middle of the mass can avoid suffocation. 

 At night, when they leave large caves or buildings where great 

 numbers of them are living, they pour out through their chosen 

 exits in such a swarm that in the dusk of early evening it has almost 

 the appearance of a cloud of smoke. 



Observations made in Mexico indicated it to be a common habit 

 for certain bats to fly a number of miles from their roosts to their 

 feeding grounds every evening, but there are no observations as to 

 the distance the Mexican free-tailed bats may go for this purpose. 

 Undoubtedly, however, they comb many square miles of territory 

 about their great roosting places. 



To what extent these bats migrate to take advantage of favorite 

 winter and summer climates, or to find favorable wintering caves, 

 is not known, but like many other bats they undoubtedly move about 

 to seek the best seasonal conditions. At times a few wander in sum- 

 mer far from their regular range, as shown by record- of scattered 

 occurrences as far north as Colorado and Kansas. Extensive migra- 

 tions, however, such as occur among some other more northern 

 species of bats, are not known in this group. 



HIBERNATION 



In winter the Mexican free-tailed bats seek caves or buildings 



where the temperature is approximately constant and not too cold, 



