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House Bat Management

Discussion and Recommendations

Bat Management Problems

Excluding bats from buildings by nonlethal methods is not new (Silver 1935) but its actual use has not been widespread. Most published studies have involved only brief applications and short-term results with little information to support claims of efficacy and safety. The use of pesticides dramatically increased after World War II and appeared to be the ultimate tool. Batproofing by nonlethal means was deemphasized. During the past 30 years, however, there have been rising anxieties concerning the environment and health hazards caused by chemicals.

Bat Conservation

The concern for bat protection began in the late 1960's when dramatic declines of once plentiful species were observed. For example, Carlsbad Caverns' millions of Mexican free-tailed bats declined to less than one-half million during the 1970's. This concern for the preservation of wildlife generated the passage of recommendations and resolutions proposed by organizations such as the World Health Organization, National Academy of Science, and many others. These groups cited a variety of reasons for the decline in populations which have been discussed earlier. Recommendations included (1) protective legislation; (2) regulation of research, (3) prohibition of chemicals which not only exacerbate the situation but further contaminate the environment; and (4) education of the general public on the reasons for bat conservation which impinge on house bat management.

Bats are often killed because they live near people who needlessly fear them and Tuttle (1979b) stated, "Their decline certainly is not in our best interests."

Bat Management in Cities and Suburbs

The Committee on Urban Pest Management of the National Research Council ( 1980) recognized that bats can be a serious urban and suburban problem. Previously attention was focused on the solution of nuisance problems and public health hazards. Integrated pest management is the suggested approach. This is based on the principles of applied ecology and a knowledge of the ecosystem. Integrated programs usually evolve slowly. Urban and suburban planners and others concerned about future research are referred to Leedy et al. (1978). Those charged with the responsibility for urban pest management decision making are referred to "Urban Pest Management," a report prepared by the Committee on Urban Pest Management (National Research Council 1980).

Research Needs

Research proposals should carefully explore, quantify, and evaluate all possible methods, materials, and costs when applying for grants (White 1975). Throughout this manual, emphasis has been placed on batproofing and the use of nonlethal methods and materials for house bat management. There are many questions still to be answered. What are the factors that govern roost selection? Where do bats go when they are dislocated and excluded from buildings? Why do bats prefer one structure to another, although both structures appear similar in all respects? Are artificial roosts a useful house bat management technique? A nonlethal chemical repellent that could safely and rapidly flush bats from buildings and then quickly dissipate without any residue would be useful. Additional studies are appropriate concerning retrofit of buildings, bat pheromones (animal communication odors), bat vocalizations, and other factors. New techniques and instrumentation, as well as adaptions of existing methods and materials, should be devised so that quantification of results is possible. Laser beams attached to electronic counters (Fenton et al. 1973); telemetry (Kolz and Corner 1975); bat detectors (Anonymous 1978), sonar, radar, and chemiluminescent tags (Buchler 1976) are useful to track bats that have been excluded from a roost and may be searching for an alternate roost. Movements of bats in and out of roosts can be monitored with electronic counters; R. E. Stebbings (personal communication) stated, "I have used automatic timed counters for 12 years. They record date, time, direction of movement, etc. all automatically."

Bat Management Legislation


A survey of Federal legislative actions, court decisions, and agency interpretations concerning the management of bats was published in "Bat management in the United States" (Lera and Fortune 1978); the agencies having primary responsibilities for bat management decisions are the Department of the Interior, the Environmental Protection Agency, and the Department of Health and Human Services (formerly the Department of Health, Education, and Welfare). It is apparent that lethal control of bats, even when there is a proven potential danger to humans, is subjected to careful scrutiny, preparation, and interagency coordination.

The United States Department of the Interior is the Nation's principal conservation agency. The FWS has broad responsibilities for wildlife conservation as mandated in various Executive orders, laws, and treaties. It has direct responsibility for bat research, protection, and management under the Fish and Wildlife Coordination Act of 1956 and the Endangered Species Act of 1973.

Because FWS policy prohibits the use of DDT and recommends against the use of anticoagulants or other chemicals that may present a threat to human health or the environment, the major management recommendation is exclusion of bats (batproofing). The only acceptable way that the FWS can manage bats in buildings and carry out its responsibilities of bat protection and conservation is to exclude unwanted bats by nonlethal methods. Bat management techniques should be selective for the offending bats, nonhazardous to human beings, and environmentally safe.


Table 2 provides a summary of States and territories of the United States with laws or regulations applying to bats, and the agency within the State that governs the laws. Information applies from 1972 to present. Some States have laws specifically mentioning bats, either providing or denying protection. Others have legislation that applies to bats only by interpretation. Bats may be considered to be non-game wildlife or indigenous State mammals. Nonspecific legislation depends on the interpretation. Some States offer protection for bats but the laws appear to be designed in the interest of public health, addressing bats as vectors of disease rather than as mammals needing protection. Some States do not have legislation but anticipate developing bat protection legislation following increases in nongame wildlife funding, public interest, or bat research. Some species have protection through endangered species laws as either Federal- or State-listed endangered species, but the same State may offer no protection for other species of bats. Without enforcement or public awareness programs, legislation may not actually accomplish the goal of protecting bats. The listing in Table 2 should not be considered complete or entirely accurate due to lack of response by some State agencies or interim changes in legislation.

Table 2.  A summary of State bat legislation.a (From Convoy 1980)
States Cave Endangered Species Hunting Collection Natural Resources Conservation Habitat access State land Public health Pesticide board
Alabama   F     P/I P/I P      
Alaska     NP/S I       P/I    
Arizona P   NP/S I            
Arkansas   F P/I I            
California     P/I I         L  
Colorado     P/S I         L  
Connecticut   F               L
Delaware                 L  
District of Columbia                 L  
Florida   F                
Georgia P F                
Guam   A P/S S            
Hawaii   ST     P/S          
Idaho   NP/I                
Illinois   F       A       L
Indiana   ST     P/S          
Iowa   ST NP/I       A     L
Kansas P                  
Kentucky   ST                
Louisiana   F NP/I I            
Maine   A P/I I           L
Maryland P F/ST     A     P/I    
Massachusetts   F P/I       P P   L
Michigan   F   I           L
Mississippi     NP/I              
Minnesota   P   I            
Missouri A F   I   P/S P      
Montana   A         P      
Nebraska     NP/I I            
New Hampshire   A NP/I             L
New Jersey   F P/I           L  
New Mexico   ST A              
New York   F NP/I           L L
North Carolina   F P/I I   A       L
North Dakota     NP/I              
Ohio   ST     P/I          
Oklahoma P                  
Oregon                 L  
Pennsylvania   F NP/I              
Puerto Rico A                  
Rhode Island                    
South Carolina   F NP/I              
South Dakota     P/I I            
Tennessee A F P/I I     P      
Utah         P/I          
Vermont   A NP/I       A      
Virginia   F                
Washington     P/A              
West Virginia P   P/I I            
Wisconsin   F                
Wyoming     NP/S              
a P = protected; NP = not protected; L = laws for bats; F = federally endangered species; A = anticipated protection; I = bats by interpretation; S = bats mentioned; ST = State endangered species.

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