Talons and beaks are viable but underutilized samples for detecting organophosphorus and carbamate pesticide poisoning in raptors

Abstract

In Europe and Africa, birds of prey, particularly vultures, are being secondarily or intentionally poisoned with acutely toxic concentrations of organophosphorus (OP) and carbamate (CM) pesticides in baited food items. By the time a mortality incident is discovered, few or no fresh carcasses, considered optimal for toxicological analysis, remain. Regardless, residues are not always detectible in typically analyzed samples (e.g., liver) because death can occur so rapidly. Without concrete forensic evidence to implicate the compounds being used and an intent to poison, ongoing local mitigation and regulatory efforts will continue to be undermined. We have sought additional means of gathering information about deliberate wildlife poisoning by testing the feasibility of detecting residues in decomposed carcasses that would not otherwise be analyzed. As likely first points of contact with poisoned food items, talons and beaks may contain detectible residues. Here, we report on the analysis of talon (n = 9) and beak (n = 7) samples conducted at the Center for Analysis and Diagnosis of Wildlife (CAD) in southern Spain from 2012-2016. Aldicarb and metabolites, methomyl and chlorfenvinphos were detected in talon samples, whereas aldicarb, chlorpyrifos and carbofuran were detected in the beaks. In several instances, the talon or beak was the only sample taken from a carcass that tested positive. We suggest that not recovering talons or heads/beaks from the field for analysis, especially in the absence of other viable carcass components, may result in pesticide residues - and deliberate poisoning incidents - being overlooked.

Keywords: talon, beak, vulture, raptor, pesticide, poisoning, forensic