Chris Maser John O. Whitaker Jr. T. Earl Kaiser Charles J. Henny 1982 <p>Background levels of DDT and its metabolites (ZDDT) were extremely low or not detected in five species of forest-dwelling bats in northeastern Oregon, i.e., areas not sprayed with DDT in 1974. Other organochlorine pesticides were rarely found and no polychlotinated biphenyls (PCBs) were detected at any time during the study. Four of five species of bats showed significant changes in Z:DDT residues in, their carcasses following the single DDT spray application. <i>Myotis californicus</i> and <i>M. volans</i> showed the highest post-spray carcass residues, 6.90 and 6.21 ppm (wet weight). respectively. <i>Lasionycteris noctivagans</i> and <i>Eptesicus fuscus</i> also showed an increase; however, <i>M. evotis</i> exhibited no significant post-spray change. By 1977 (3 years post-spray), residues declined and only <i>M. californicus</i> and <i>M. volans</i> contained levels that were significantly above those in the nonspray (control) area. We are uncertain if the elevated residue levels resulting from the DDT-spray project adversely affected any of the bats. An attempt to relate bat carcass ZDDT residues to food habits, through analysis of stomach contents, yielded no clear relationships.</p> application/pdf en Northwest Science Association Organochlorine residues in bats after a forest spraying with DDT article