Quantitative evaluation of control tools for managing invasive species is necessary to assess overall effectiveness and individual variation in treatment susceptibility. Invasive brown treesnakes (Boiga irregularis) on Guam have caused severe ecological and economic effects, pose a risk of accidental introduction to other islands, and are the greatest impediment to the reestablishment of extirpated native fauna. An aerial delivery system for rodent-based toxic baits can reduce brown treesnake abundance and heterogeneity among individuals may influence bait attraction or toxicant susceptibility. Previous baiting trials have either been simulated aerial treatments or relied on slightly different bait capsule compositions and the results of aerial delivery of toxic baits under operational conditions may not be directly comparable. We monitored 30 radio-tagged adult snakes (990–1,265 mm snout-vent length) during an aerial baiting operation in a 55-ha area using transmitters equipped with accelerometers and receivers programed to display a status code indicating mortality if a snake failed to move for >24 hours. We used known-fate models to estimate mortality and evaluate a priori hypotheses explaining differences in mortality based on size, sex, and treatment effects. Eleven radio-tagged snakes died in the aerial baiting treatment period (0.37, 95% CI = 0.21–0.55) and no individuals (0.00, 95% CI = 0.00–0.04) died during the non-treatment period. Our data provide strong evidence for an additive size-based treatment effect on mortality, with smaller adults (0.59, 95% CI = 0.35–0.80) exhibiting higher mortality than larger snakes (0.14, 95% CI = 0.02–0.37) but did not support a sex effect on mortality. The high mortality of snakes during the treatment period indicates that aerial baiting can reduce brown treesnake abundance, but further refinement or use in combination with other removal tools may be necessary to overcome size-based differences in susceptibility and achieve eradication. © 2021 The Authors. The Journal of Wildlife Management published by Wiley Periodicals LLC on behalf of The Wildlife Society.

中文翻译：

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空中施用毒饵后棕树蛇的死亡率

有必要对用于管理入侵物种的控制工具进行定量评估，以评估治疗易感性的整体有效性和个体差异。入侵的棕色树蛇) 对关岛造成严重的生态和经济影响，造成意外引入其他岛屿的风险，并且是重建已灭绝的本地动物群的最大障碍。基于啮齿动物的有毒诱饵的空中输送系统可以降低棕色树蛇的丰度，个体之间的异质性可能会影响诱饵吸引力或毒物敏感性。以前的诱饵试验要么是模拟空中处理，要么依赖于略有不同的诱饵胶囊成分，在操作条件下空中投放有毒诱饵的结果可能无法直接比较。我们监测了 30 条无线电标记的成年蛇（990-1，265 毫米鼻子-通风口长度）在 55 公顷的区域进行空中诱饵操作时，使用配备有加速计和接收器的发射器，这些发射器被编程为显示状态代码，如果一条蛇超过 24 小时没有移动，就会显示死亡率。我们使用已知命运模型来估计死亡率并评估先验解释基于大小、性别和治疗效果的死亡率差异的假设。11 条放射性标记蛇在空中诱饵治疗期间死亡 (0.37, 95% CI = 0.21–0.55)，在非治疗期间没有个体 (0.00, 95% CI = 0.00–0.04) 死亡。我们的数据为基于体型的附加治疗对死亡率的影响提供了强有力的证据，体型较小的成年蛇 (0.59, 95% CI = 0.35–0.80) 的死亡率高于较大的蛇 (0.14, 95% CI = 0.02–0.37)，但没有支持性别对死亡率的影响。处理期间蛇的高死亡率表明空中诱饵可以减少棕树蛇的数量，但可能需要进一步改进或与其他清除工具结合使用，以克服基于大小的敏感性差异并实现根除。© 2021 作者。由 Wiley Periodicals LLC 代表野生动物协会出版的《野生动物管理杂志》。