Assessment of the exposure to anticoagulant rodenticides in three raptor species of Taiwan

SHIAO-YU HONG (, Graduate Institute of Bioresources, National Pingtung University of Science & Technology, Pingtung, Taiwan.
HUI-SHAN LIN and YUAN-HSUN SUN, Institute of Wildlife Conservation, National Pingtung University of Science & Technology, Pingtung, Taiwan.
CHENG-TE YAO and TE-EN LIN, Endemic Species Research Institute, Nantou, Taiwan. TSYR-HORNG SHYU, Agricultural Chemicals and Toxic Substances Research Institute, Taichung, Taiwan.
WEN-LOUNG LIN, Taichung Wildlife Rescue Group, Taichung, Taiwan.

Raptor Research Foundation 2017 Annual Meeting
Dates: 7-12th November 2017
Location: Sheraton Salt Lake City, Salt Lake City, Utah, USA
Te-En Lin

Anticoagulant rodenticides (AR) are used worldwide for vertebrate pest control but also cause serious secondary poisoning to predators. Large-scale monitoring has been conducted in Europe and North American, however, very few cases were reported in Asia. This work aimed at first- and second- generation ARs residues in livers of the three common raptor species in Taiwan: Black-shouldered Kite (BK, Elanus caeruleus, n = 43), Crested Goshawk (CG, Accipiter trivirgatus, n = 44), and Collared Scops-owl (CS, Otus lettia, n = 41). Samples mainly came from rescue centers in the period 2013-2016. The AR exposed rate were 88.4% (BK)、59.1% (CG), and 56.1% (CS). Average residue values were 0.152 (SD = 0.212)、0.051 (SD = 0.043), and 0.057 (SD = 0.075) mg/kg, respectively. There were 35% BK exceeding the speculate threshold of toxicity (0.1 mg/kg). In the AR detected samples (n = 87), 55.2% was detected more than one kind of AR, and maximum of six (in a CG sample). The most frequently detected ARs were Brodifacoum (79.3%), Flocoumafen (51.7%), and Bromadiolone (27.6%). BK had the highest exposed rate and residue value was due to its specialized habit of rat-eater. The Taiwan government has been promoting an anti-rodent campaign and hundreds tons of second-generation ARs were provided to farmers and inhabitants for free every year from 1980s. This is the first record to prove that secondary poisoning of ARs to raptors is a serious and common phenomenon in Taiwan. The rodent control policy has made some adjustments accordingly.