摘要:Twenty-four specimens of southbound migratory passerines comprising 13 species were collected in northeastern Louisiana during 1986, and were subjected to gas-chromatography analyses for organochlorine pesticide compounds. Eleven of the specimens analyzed (46%) were positive for pesticides. The compounds detected were in trace amounts ranging from 1.37 to 200.14 ppb. The data indicated a further decline in pesticide burdens in birds since the ban on DDT. It also supported the hypothesis that a post-mortem breakdown of DDT to DDE may occur in avian tissues. Itis hypothesized that northbound migrants may have higher pesticide burdens than fall migrants considering the continued usage of pesticides in their wintering grounds south of the United States border.