AbstractAbout 1,150 individuals of 38 species of Passeriformes and other small birds were collected in 1980 at 36 locations in eight western U.S. states for organochlorine (OC) chemical analysis. The bird carcasses (less beak, tarsi, gastrointestinal tract, and feathers) were combined by species and location (4 to 15 specimens per sample) into 124 composited samples for analysis. Also analyzed were 77 single specimens of four species, to assess variation in residue concentrations in individual birds. The chemicals detected (greater than 0.05 ppm) were the following (in order of frequency): DDE, polychlorinated biphenyls (PCBs), hexachlorocyclohexane (HCH), heptachlor epoxide, oxychlordane, dieldrin and toxaphene. DDE accounted for 72 of total OC concentrations (ppm DDE/ppm total OCs) overall and PCBs accounted for 3. DDE mean (geometric) residues were highest in tree swallows (Tachycineta bicolorVieillot), 12.0 ppm; killdeer (Charadrius vociferusL.), 5.9 ppm; and Brewer's blackbirds (Euphagus cyanocephalusWagler), 2.7 ppm. Eight migratory species showed mean DDE residues 13 times higher than those in four resident species (1.3 vs. 0.1 ppm,p<0.05), but PCB residues were similar (0.03 vs. 0.02 ppm). Insectivorous species showed higher DDE, PCB and total OC residues than did either omnivores or granivores (p<0.05). Males of some species showed higher residues of DDE, PCBs and total OCs than did females (p<0.05). DDE residues, but not PCBs, in killdeer, Brewer's blackbirds and violet‐green swallows (Tachycineta thalassinaSwainson) were significantly related (0.01展开▼
