Unexpected exposure of Andean condors (Vultur gryphus) to pharmaceutical mixtures

Potential exposure of the Andean Condor (Vultur gryphus) to pharmaceuticals is of high conservation interest, as these compounds can produce catastrophic consequences for populations of avian scavengers. Due to the extensive livestock management in most of Patagonia, we expected Andean condors to be rarely exposed to veterinary pharmaceuticals through scavenging of free-ranging livestock. Unexpectedly, we found a high prevalence (78.6 %) of pharmaceuticals in the plasma of a small sample of randomly captured condors (n = 14), of all age classes and sexes. The antibiotic enrofloxacin was detected in all 11 drug-positive condors (78.6 %). Two antibiotics and two non-steroidal anti-inflammatory drugs (NSAIDs) were found simultaneously or in combinations of two or three different pharmaceuticals in 3 of the 14 (21.4 %) condors: marbofloxacin and phenylbutazone were found in a single adult female together with enrofloxacin, while flunixin meglumine was found in two adult males and also in the presence of enrofloxacin. Our study suggests that livestock grazing in the vast Patagonian region may be subject to more frequent medication than expected a priori. Today, it should not be assumed that livestock in remote, sparsely populated, or low-income areas are free of veterinary pharmaceuticals with a possible negative impact on wildlife and public health.