Ecotoxicological Assessment of Metal and Metalloid Contamination in Terrestrial Predatory Birds from Northeast China

Birds serve as ecological bioindicators of metal/metalloid contamination due to their continuous environmental exposure. In northeast China, where metal/metalloid pollution is a serious environmental issue driven by anthropogenic activities, its effects on birds remain understudied. This study analyzed tail feathers from ten terrestrial raptor species across four families to assess ecological risks from cadmium (Cd), lead (Pb), arsenic (As), zinc (Zn), copper (Cu), and manganese (Mn). Results showed that Tiger Shrike (Lanius tigrinus) had the highest As (54.35 ± 69.76 mg kg⁻¹) and Cd (5.45 ± 3.94 mg kg⁻¹) residues, followed by Brown Shrike (Lanius cristatus), which also exhibited elevated Pb concentrations (33.61 ± 93.20 mg kg⁻¹). This suggests Shrikes (Laniidae) are more susceptible to metal/metalloid contamination. Significant differences in pollutant levels were found between Little Owl (Athene noctua) and Long-Eared Owl (Asio otus), despite similar feeding behaviors, indicating species-specific sensitivity. Stable carbon isotopic (δ¹³C) values suggested that predatory birds feeding in habitats with lower δ¹³C values may have greater exposure to metal/metalloid pollutants. All studied predatory bird species, except Long-Eared Owl, showed at least one metal/metalloid concentration above toxicity thresholds, highlighting potential ecological risks. These findings emphasize the need for stringent control of anthropogenic metal emissions to mitigate adverse effects on wildlife and human health.