ABSTRACT In many animal species, individuals re-use the breeding site they used in the previous breeding season. Consequently, they accrue benefits including reduced time searching for a territory, and enhanced predator avoidance. Many seabirds display high levels of nest-site fidelity. We sought to determine whether nest-site fidelity occurs in Red-tailed Tropicbirds (Phaethon rubricauda) breeding at Ashmore Reef (eastern Indian Ocean) by recording the nest location of individually-marked birds across three years (2012–2014). We found that Red-tailed Tropicbirds at this surface-nesting colony were highly faithful to their previous nest-site, with a median distance between successive nests of just 13.4 m. By using digitised vegetation maps for Ashmore Reef, we provide quantitative evidence that Red-tailed Tropicbird nest-site fidelity is not driven by a lack of suitable vegetated sites. These findings have important management implications because breeding success at this small, regionally-significant Red-tailed Tropicbird colony is negatively affected by an invasive species, the tropical fire ant (Solenopsis geminata). Using localised ant baiting around known Red-tailed Tropicbird nest-sites may confer benefits on current and future tropicbird breeding attempts. We estimated the financial cost per treatment to bait the 0.85 ha within 13.4 m of known Red-tailed Tropicbird nest-sites, an area expected to encompass half of all subsequent breeding attempts, to be low. This represents a cost-effective interim management strategy prior to any island-wide eradication programme. Therefore, we recommend localised ant baiting around tropicbird nests within an adaptive management framework such that optimum baiting parameters can be resolved (e.g., baiting frequency, most effective baiting radius).

中文翻译：

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红尾热带鸟的巢址保真度告知在 Ashmore Reef 进行本地化蚂蚁诱饵策略的成本

摘要 在许多动物物种中，个体会重复使用他们在上一个繁殖季节使用过的繁殖场所。因此，它们产生的好处包括减少寻找领土的时间和增强的捕食者回避。许多海鸟表现出高水平的巢址保真度。我们试图通过记录三年（2012 年至 2014 年）在阿什莫尔礁（东印度洋）繁殖的红尾热带鸟类（Phaethon rubricauda）的巢穴位置，确定巢址保真度是否发生。我们发现在这个地表筑巢的红尾热带鸟非常忠实于它们以前的巢穴，连续巢穴之间的中位距离仅为 13.4 m。通过使用 Ashmore Reef 的数字化植被图，我们提供的定量证据表明，红尾热带鸟巢穴的保真度不是由于缺乏合适的植被地点所致。这些发现具有重要的管理意义，因为在这个具有区域意义的小型红尾热带鸟群落的繁殖成功受到入侵物种热带火蚁（Solenopsis geminata）的负面影响。在已知的红尾热带鸟巢穴周围使用局部蚂蚁诱饵可能会为当前和未来的热带鸟繁殖尝试带来好处。我们估计，在 13.4 m 内已知红尾热带鸟巢穴的 0.85 公顷范围内诱饵的每次处理的财务成本较低，预计该区域将包含所有后续繁殖尝试的一半。这代表了在任何全岛根除计划之前的具有成本效益的临时管理战略。所以，