Estimating pesticide burdens of bats from guano analyses

Bat guano was first collected and analyzed for environmental pollutants in the early 1970's (REIDINGER 1972:53-64; PETIT & ALTENBACH 1973). Later analyses of both guano and bats from two roosts indicated a correspondence between levels of organochlorine residues in guano and in bat carcasses from the same colony (CLARK & PROUTY 1976). Gray myotis (mytosis grisescens) were found dead with lethal brain levels of dieldrin in two colonies where dieldrin levels in guano were high relative to other colonies (CLARK et al. 1978, 1980). We collected and analyzed both guano samples and bats found dead or killed accidentally during handling from numerous roosts of several bat species. The objective of this study was to determine whether a correlation existed between organochlorine residues in guano and in bat carcasses.