ORGANOCHLORINE CONCENTRATIONS IN POTENTIAL AVIAN PREY OF BREEDING PEREGRINE FALCONS IN NORTH-CENTRAL NEW-MEXICO

Despite the federal ban of DDT since 1972, some southwestern populatio ns of peregrine falcons (Falco peregrinus anatum) still exhibit extrem ely low natural production and continue to accumulate high levels of D DE. During 1985, we collected 35 potential species of migrant and resi dent prey of peregrine falcons in north-central New Mexico to determin e if local peregrine falcons are exposed to DDE on the breeding ground s. Thirteen (37.1%) of the 35 species pools contained DDE residues >1. 0 ppm. Say's phoebe (Sayornis saya; 22.01 ppm), killdeer (Charadrius v ociferus; 13.49 ppm), American pipit (Anthus rubescens; 11.63 ppm), we stern meadowlark (Sternella neglecta; 6.25 ppm), and Brewer's blackbir d (Euphagus cyanacephalus; 5.28 ppm) pools had DDE residues >5.0 ppm. DDE concentrations were not significantly related to prey diet but mig ration status was a significant effect with DDE residues lowest in res idents (geometric mean = GM = 0.08 ppm), intermediate in weakly migrat ory species (GM = 0.37 ppm) and highest in strongly migratory species (GM = 1.63 ppm). Based on results of this study and a review of the li terature, we conclude that peregrine falcons utilizing this study area are still faced with a potential source of DDE contamination.