Data from: Deceiving predators: linking distraction behavior with nest survival in a ground-nesting bird

Individual behavior that minimizes predation risk is favored by natural selection. Ground-nesting birds employ different defensive behaviors as part of their antipredator strategies because they nest where a wide range of predators have access. We investigated the influence of distraction displays on breeding success in the Kentish Plover, Charadrius alexandrinus, in order to explore the role of the defensive behavior on nest survival. We quantified the intensity of defensive behavior of adult plovers in response to nest disturbance caused by an approaching researcher, by ranking display types according to the intensity and exposure to predation. We also examined sex differences in nest defense to determine whether the existence, intensity, and consistency of individual defensive behaviors could have an impact on nest survival. We used the nest survival model in Program MARK to estimate daily survival rates of nests and to examine the influence of temporal, behavioral, and habitat variables on nest success. Our results show a positive correlation between male and female defense behaviors within pairs and that nests in which parents invested more on defense survived longer. Nevertheless, there were differences in the risks assumed by the 2 members of breeding pairs in nest defense, with females performing riskier defensive behaviors than males. The top-ranked nest survival models included combined additive effects of site, season, habitat type, nest exposure, and the defense behavioral response of females as best predictors. Finally, our study highlights that increased risk assumption in offspring defense is advantageous in terms of individual fitness.能够降低捕食风险的个体行为会受到自然选择的青睐。地面筑巢鸟类因巢址暴露于多种捕食者的侵扰范围中，故演化出多样防御行为作为反捕食策略的组成部分。为探究防御行为对巢存活的作用，我们以环颈鸻（Charadrius alexandrinus）为研究对象，考察了诱敌分散行为（distraction display）对其繁殖成功率的影响。我们根据行为强度与捕食暴露风险对诱敌分散行为类型进行分级，以此量化成年环颈鸻应对逐步靠近的研究人员所引发的巢干扰时的防御行为强度。此外，我们还考察了巢防御行为中的性别差异，以明确个体防御行为的存在性、强度与一致性是否会对巢存活率产生影响。我们使用Program MARK软件中的巢存活模型，估算巢的日存活率，并分析时间、行为、生境三类变量对繁殖成功率的影响。研究结果显示，配对个体间的雌雄防御行为呈显著正相关，且双亲投入更多防御行为的巢存活率更高。尽管如此，繁殖配对的双方在巢防御中承担的风险存在差异，雌性实施的防御行为相较于雄性具有更高的风险性。最优拟合的巢存活模型将生境位点、繁殖季、生境类型、巢暴露程度以及雌性的防御行为响应作为最佳预测因子的组合加性效应纳入其中。综上，本研究表明，在子代防御中承担更高风险，对个体适合度而言具有显著优势。