Evaluating contamination in the Red-billed Chough Pyrrhocorax pyrrhocorax through non-invasive sampling

Concentrations of 16 polycyclic aromatic hydrocarbons (PAHs), 19 polybrominated diphenyl ethers (PBDEs), 7 polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), isomers and metabolites of dichlorodiphenyltrichloroethane (DDTs) and Hexachlorocyclohexane (HCHs) were measured in the feathers of the Red-billed Chough Pyrrhocorax pyrrhocorax, a rare and protected corvid species inhabiting rural and mountainous areas. Feathers were collected in the wild from seven sites in the Iberian Peninsula, one in La Palma, Canary Islands, Spain and one site in Italy. HCH isomers and HCB resulted always under the detection limit. PAHs were found only in the Italian population (range 39.3–54.6 ng/g wet weight in the three subsamples). For PBDEs, the concentrations ranged from 135 to 11,753 pg/g (mean 1560 ± 3415 pg/g w.w.). Only one sample collected in the most urbanized Spanish site in 1990 exceeded 2000 pg/g. Twenty years later in the same site the concentration resulted very low. Six Spanish areas from the same meta-population, and one island population at La Palma showed a low contamination by pp'DDE (3.2 ± 3.3 ng/g w.w., range for positive samples 1.7–10.1 ng/g w.w.). PCBs were found only in two Spanish locations with the 52 and the 138 congeners. Overall the species showed low to intermediate levels of contamination in feathers probably due to its intermediate trophic position and/or to the integrity of its environment.