If the roost is not completely dislodged, it is necessary 

 to ensure that all bats are out of the buildings before proofing 

 work is completed. Normally, during the warmer months when bats" 

 are active, all occupants leave the roost within 1^ to 20 minutes 

 after the first one starts out. If they have been disturbed, how- 

 ever, the noiinal routine may be upset considerably, and one or two 

 of the most-used openings should temporarily be left open. In the 

 evening after the last bat has left the roost for feeding, close the 

 remaining openings. If a number of entrances have been used, wait 

 two or three days before attempting to close the last one, thus 

 allowing all the occupants to learn to enter through this last 

 opening. It can then be easily located and closed. If any entrances 

 have been overlooked, the bats will soon find them, so it is neces- 

 sary to watch the building closely at dusk for several evenings. 



Fumigation ? In cases where the use of repellents and proofing will 

 not suffice, it may be necessary to destroy the bats. Best results 

 can be obtained by fumigation with gas. Calcium cyanide is the 

 material most generally used for this purpose. Operations involving 

 space fumigation are dangerous and must never be attempted by inex- 

 perienced persons. Only trained professionals, qualified to handle 

 the materials, should be entrusted with the task. 



The use of poisoned bait is impractical since bats feed 

 primarily upon flying insects they catch in the air. 



Bat destruction by the above method, while accomplishing 

 the immediate objective, has several disadvant^es, as carcasses 

 not recovered decompose with a resultant displeasing odor. Further, 

 it gives no degree of permanency, for as s.oon as the space has been 

 cleared of gas it is ready for new occupants if no bat-proofing has 

 been done. For the reasons mentioned, proofing, where practical, 

 is recommended as the most satisfactory and permanent means of bat 

 control. 



For those interested in details about bats, their habits 

 and characteristics, a selected group of references is listed on 

 Page U. 



