Wild kea response to non-toxic baits with and without deer repellent – implications for management

1080 toxin (sodium fluoroacetate) is used in New Zealand for possum (<i>Trichosurus vulpecula</i>) and ship rat (<i>Rattus rattus</i>) control but can result in unintentional by-kill of native (e.g. kea <i>Nestor notabilis</i>) and non-native (e.g. deer) fauna. A newly developed deer repellent (Prodeer) in 1080 bait has proved highly effective in reducing deer by-kill while not impacting target pest efficacy. The ingredients in Prodeer bait are undisclosed due to commercial sensitivity, thus it is unknown whether this bait type increases acceptability and palatability to kea and increases risk over and above that posed by the standard (RS5) bait type normally used in aerial poisoning operations. During choice trials comparing kea responses to, and consumption of, non-toxic Prodeer and RS5 baits at alpine sites around Arthur’s Pass National Park and central Westland we found kea Prodeer and RS5 consumption (per interaction and total) were not significantly different. Most individuals consumed substantially less of both bait types than the estimated lower 1080 LD50 threshold for kea, and vastly less than captive kea consume. We conclude that 1080 operations using Prodeer are unlikely to pose a risk significantly over and above that already presented to kea in standard RS5 1080 operations.

1080毒素（氟乙酸钠，sodium fluoroacetate）目前在新西兰被用于防控帚尾袋貂（Trichosurus vulpecula）与黑鼠（Rattus rattus），但该药剂可能造成本土动物（如啄羊鹦鹉Nestor notabilis）及非本土动物（如鹿）的非靶标误杀。一种新近研发的添加于1080饵剂中的鹿驱避剂（Prodeer）已被证实可在不影响靶标害虫害鼠防控效力的前提下，显著降低鹿类的非靶标误杀量。由于商业保密需求，Prodeer饵剂的成分尚未公开，因此目前尚不明确该类饵剂是否会提升啄羊鹦鹉对其的接受度与适口性，进而相较于航空投饵作业中常规使用的标准饵剂（RS5）带来更高的风险。本研究在亚瑟隘口国家公园周边及西海岸中部的高山生境中开展了选择性取食试验，对比啄羊鹦鹉对无毒Prodeer饵剂与RS5饵剂的反应及取食量，结果发现啄羊鹦鹉对两类饵剂的单次取食量及总取食量均无显著差异。绝大多数个体对两类饵剂的取食量均远低于啄羊鹦鹉的1080毒素半数致死量（LD50）下限估算值，且远低于圈养啄羊鹦鹉的常规取食量。本研究结论为：使用Prodeer饵剂的1080投饵作业，对啄羊鹦鹉造成的风险不会显著高于标准RS5型1080投饵作业已带来的风险。