[Texascavers] RE: heaters for bats

[Nancy Weaver]

How on earth have bats managed to survive so long without thoughtful 
human intervention?  Or any other part of nature?  Good thing we can 
now remedy nature's poor planning.  I wonder what the displacement 
factor in the production of the heater boxes is - ie how many bats or 
habitat does it cost environmentally to produce each of these things?

Nancy