Nest Usurpation by Non-native Birds and the Role of People in Nest Box Management

Abstract: Invasive species are a threat to global biodiversity, yet the impacts of invasive birds on the native birds with which they compete are understudied. Humans have a long history of providing and managing nest boxes to support native birds; however, their management of non-native birds has received limited research attention. We surveyed people who maintain nest boxes in North America to examine the extent of interference competition for nest sites between native and non-native birds and the human behaviors intended to reduce nest site competition. Our specific objectives were to examine observations of nest usurpation of native birds by non-native birds across the U.S. and Canada, to ascertain whether and how people who maintain nest boxes control non-native bird species in favor of native species, and to quantify various factors correlated with the likelihood of engaging in management activities. We found that nearly one-third of the 871 respondents had observed a non-native species usurp a nest box occupied by a native species. Among respondents who reported nest usurpations, species-specific nest usurpation rates varied (range = 3–35%). We found that witnessing a nest usurpation is the most important predictor of whether or not someone will engage in management activities. Management activity was also associated with the extent to which respondents believed non-native birds to be a problem at the continental scale. Our study shows that people’s observations of threats from introduced species are correlated with the environmental management actions people take, and that these actions can mitigate the threats, and potentially support the survival of native birds. In order to interpret and use the data, you will need to download the manuscript of the same name from Conservation Science and Practice, along with the supporting information. We include SAS code and two data files referenced in the manuscript.摘要：外来入侵物种对全球生物多样性构成重大威胁，但入侵鸟类与本土鸟类间的竞争及其产生的生态影响却未得到充分研究。人类长期以来通过设置与管理巢箱助力本土鸟类繁衍，然而针对人类管控非本土鸟类的相关研究却十分有限。本研究针对北美地区巢箱维护者开展问卷调查，旨在探究本土与非本土鸟类间巢址干扰竞争（interference competition）的程度，以及人类为缓解巢址竞争所采取的行为模式。本研究的具体目标包括：一是考察美国与加拿大境内非本土鸟类侵占本土鸟类巢箱的观测记录；二是明确巢箱维护者是否会采取管控非本土鸟类的措施以保护本土鸟类，并探究其具体管控方式；三是量化与参与管控活动可能性相关的各类影响因素。研究结果显示，在871名受访者中，近三分之一的人曾观测到非本土鸟类侵占已被本土鸟类占据的巢箱。在报告过巢箱侵占事件的受访者中，不同物种的巢箱侵占率存在差异，范围为3%至35%。研究发现，亲眼目睹巢箱侵占事件是影响受访者是否采取管控措施的最关键预测因子；此外，管控行为还与受访者认为非本土鸟类在大陆尺度上构成问题的严重程度密切相关。本研究表明，民众对入侵物种威胁的认知与其采取的环境管理行动存在显著关联，而这些管控措施能够缓解外来物种带来的威胁，进而助力本土鸟类的种群存续。若要解读并使用本数据集，请从《Conservation Science and Practice》期刊下载同名论文及其配套补充材料。本数据集包含论文中提及的SAS代码与两份数据文件。