Data from: Housework or vigilance? Bilbies alter burrowing activity under threat of predation by feral cats

Behavioral adjustments to predation risk not only impose costs on prey species themselves but can also have cascading impacts on whole ecosystems. The greater bilby (Macrotis lagotis) is an important ecosystem engineer, modifying the physical environment through their digging activity, and supporting a diverse range of sympatric species that use its burrows for refuge and food resources. The bilby has experienced severe decline over the last 200 years, and the species is now restricted to approximately 20% of its former distribution. Introduced predators, such as the feral cat (Felis catus), have contributed to this decline. We used camera traps to monitor bilby burrows at four sites in Western Australia, where bilbies were exposed to varying levels of cat predation threat. We investigated the impact of feral cats on bilby behavior at burrows, particularly during highly vulnerable periods when they dig and clear away soil or debris from the burrow entrance as they perform burrow maintenance. There was little evidence that bilbies avoided burrows that were visited by a feral cat; however, bilbies reduced the time spent performing burrow maintenance in the days following a cat visit (p=0.010). We found the risk posed to bilbies varied over time, with twice the cat activity around full moon compared with dark nights. Bilby burrows are such valuable resources for ecosystem functioning that bilby predation by feral cats, as well as even indirect impacts on bilby behavioral responses to perceived predation risk, together may have a substantial ecosystem impact.

针对捕食风险的行为调整，不仅会给猎物种群带来直接生存代价，还会对整个生态系统产生级联效应。兔耳袋狸（greater bilby, *Macrotis lagotis*）是一类重要的生态系统工程师：它们通过掘土活动改变栖息地的物理环境，同时为多种同域分布物种提供庇护所与食物资源——这些物种会利用兔耳袋狸的洞穴作为栖息或觅食场所。在过去200年间，兔耳袋狸种群经历了严重的衰退，目前其分布范围仅占历史分布的约20%。外来捕食者，如野猫（*Felis catus*），是导致其种群衰退的重要诱因之一。本研究在西澳大利亚州的4个监测点位利用红外相机陷阱对兔耳袋狸洞穴进行监测，这些点位中的兔耳袋狸面临着不同程度的野猫捕食威胁。我们探究了野猫对兔耳袋狸在洞穴周边行为的影响，尤其是在兔耳袋狸开展洞穴维护作业——即挖掘并清理洞穴入口处的土壤与杂物——这一极易遭遇捕食的脆弱时段的行为变化。研究未发现兔耳袋狸会主动回避被野猫到访过的洞穴；但数据显示，在野猫到访后的数日内，兔耳袋狸用于洞穴维护的时长显著缩短（p=0.010）。我们发现兔耳袋狸面临的捕食风险存在时间异质性：满月时段的野猫活动频次是暗夜时段的两倍。兔耳袋狸洞穴对生态系统功能而言是极具价值的资源，因此野猫对兔耳袋狸的直接捕食行为，以及其对兔耳袋狸应对感知捕食风险的行为所产生的间接影响，二者共同作用可能会对生态系统造成显著影响。