ABSTRACT Establishing appropriate conservation management objectives and actions for seabirds requires timely detection of changes in their populations. However, obtaining regular accurate measures of seabird population size and trends can be difficult due to logistical and financial constraints in accessing remote breeding sites. The Short-tailed Shearwater (Ardenna tenuirostris) is a wide-ranging, burrow-nesting Procellariiform with an estimated breeding population size of ca 23 million individuals. Despite its ecological significance, there is currently limited monitoring of the species. In the present study, eight acoustic data loggers were deployed across six sites over two breeding seasons to assess the efficacy of acoustic monitoring. Five acoustic indices were used to investigate vocal activity over the breeding season, detect phenology events, and to determine the most accurate period to assess the density of occupied nests. The general pattern over the breeding season was similar for several of the acoustic indices and reflected colony attendance patterns. Linear regressions fitted to the normalised difference soundscape index values and density of occupied nests (burrows·m−2) revealed significant relationships in both the incubation and chick-rearing. The results suggest that passive acoustic monitoring could be used as an effective method to predict nesting density in Short-tailed Shearwater breeding colonies. Used in conjunction with information on the breeding colony area, this could enable regular estimates of colony population size. Such information is crucial for the early detection of population trajectory changes. The method may also be applicable for other burrow- or surface-nesting seabirds for which regular wide-spread monitoring currently proves difficult.

中文翻译：

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为澳大利亚数量最多的海鸟——短尾海鸥 (Ardenna tenuirostris) 开发一种被动声学监测技术

摘要 为海鸟制定适当的保护管理目标和行动需要及时发现其种群的变化。然而，由于进入偏远繁殖地点的后勤和财务限制，定期准确测量海鸟种群规模和趋势可能很困难。短尾海鸥 (Ardenna tenuirostris) 是一种分布广泛的穴居 Procellariiform，估计繁殖种群规模约为 2300 万只。尽管具有生态意义，但目前对该物种的监测有限。在本研究中，在两个繁殖季节的六个地点部署了八个声学数据记录器，以评估声学监测的功效。五个声学指数用于调查繁殖季节的声音活动，检测物候事件，并确定最准确的时期来评估被占领的巢穴的密度。繁殖季节的总体模式与几个声学指数相似，并反映了群体出勤模式。拟合归一化​​差异音景指数值和被占用巢穴密度 (洞穴·m-2) 的线性回归揭示了孵化和雏鸡饲养的显着关系。结果表明，被动声学监测可作为预测短尾海鸥繁殖群筑巢密度的有效方法。结合繁殖种群面积的信息，这可以使种群数量的定期估计成为可能。这些信息对于早期检测人口轨迹变化至关重要。