U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Corvallis, OR, 97331, USA.
U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Corvallis, OR, 97331, USA.
Environ Pollut. 2022 Oct 15;311:119925. doi: 10.1016/j.envpol.2022.119925. Epub 2022 Aug 18.
Anticoagulant rodenticides (ARs) are widespread environmental contaminants that pose risks to scavenging birds because they routinely occur within their prey and can cause secondary poisoning. However, little is known about AR exposure in one of the rarest avian scavengers in the world, the California condor (Gymnogyps californianus). We assessed AR exposure in California condors and surrogate turkey vultures (Cathartes aura) to gauge potential hazard to a proposed future condor flock by determining how application rate and environmental factors influence exposure. Additionally, we examined whether ARs might be correlated with prolonged blood clotting time and potential mortality in condors. Only second-generation ARs (SGARs) were detected, and exposure was detected in all condor flocks. Liver AR residues were detected in 42% of the condors (27 of 65) and 93% of the turkey vultures (66 of 71). Although concentrations were generally low (<10 ng/g ww), 48% of the California condors and 64% of the turkey vultures exposed to ARs exceeded the 5% probability of exhibiting signs of toxicosis (>20 ng/g ww), and 10% and 13% exceeded the 20% probability of exhibiting signs toxicosis (>80 ng/g ww). There was evidence of prolonged blood clotting time in 16% of the free-flying condors. For condors, there was a relationship between the interaction of AR exposure index (legal use across regions where condors existed) and precipitation, and the probability of detecting ARs in liver. Exposure to ARs may complicate recovery efforts of condor populations within their current range and in the soon to be established northern California experimental population. Continued monitoring of AR exposure using plasma blood clotting assays and residue analysis would allow for an improved understanding of their hazard to condors, particularly if paired with recent movement data that could elucidate exposure sources on the landscape occupied by this endangered species.
抗凝血灭鼠剂（ARs）是广泛存在的环境污染物，对食腐鸟类构成风险，因为它们经常出现在其猎物中，并可能导致二次中毒。然而，对于世界上最稀有的鸟类之一——加州秃鹫（Gymnogyps californianus）的 AR 暴露情况，人们知之甚少。我们评估了加州秃鹫和替代火鸡秃鹫（Cathartes aura）中的 AR 暴露情况，以评估拟议的未来秃鹫群面临的潜在危害，方法是确定施用量和环境因素如何影响暴露情况。此外，我们还研究了 AR 是否与秃鹫的凝血时间延长和潜在死亡率有关。仅检测到第二代 ARs（SGARs），并且在所有秃鹫群中都检测到了暴露。在 42%的秃鹫（65 只中的 27 只）和 93%的火鸡秃鹫（71 只中的 66 只）中检测到肝脏 AR 残留。尽管浓度通常较低（<10 ng/g ww），但 48%的暴露于 AR 的加州秃鹫和 64%的火鸡秃鹫超过了 5%表现出中毒迹象的概率（>20 ng/g ww），10%和 13%超过了 20%表现出中毒迹象的概率（>80 ng/g ww）。在 16%的自由飞行的秃鹫中发现了凝血时间延长的证据。对于秃鹫，AR 暴露指数（在秃鹫存在的地区的合法使用）与降水之间的相互作用，以及在肝脏中检测到 AR 的概率之间存在关系。在其当前范围内和即将建立的北加利福尼亚实验种群中，暴露于 AR 可能会使秃鹫种群的恢复工作复杂化。通过使用血浆凝血测定和残留分析继续监测 AR 暴露情况，可以更好地了解它们对秃鹫的危害，特别是如果与最近的运动数据相结合，可以阐明该濒危物种栖息地的暴露源。
