Data and code to analyze reproductive rates of California Condors in the first two decades of reintroduction in California

In the first comprehensive assessment of the reproductive rates of critically endangered California Condors (Gymnogyps californianus) recovering from complete extirpation in the wild, we analyzed 20 years (1999–2018) of data from condor flocks in southern and central California. We found that several anthropogenic threats affected reproductive rates: (1) coastal space use by female condors was associated with lower hatch probability, presumably due to marine mammal foraging and associated DDE exposure, (2) trash ingestion by chicks decreased fledging probability prior to implementation of trash management in 2007, and (3) all parent deaths during rearing resulted in chick or early fledgling deaths, and most parental deaths were due to lead poisoning. We also detected several effects on reproductive rates of the complex individual-based management of condors, which involves ongoing releases of captive-bred individuals and health interventions including treatment of lead poisoning. Recrui..., Observations consisted of near-daily attempts to locate each individual visually or by telemetry signal. Starting in 2002 in the southern flock and 2008 in the central flock, observations at cameras established at proffered feeding stations were also recorded and included in our data. Given the intensive monitoring, we believe that essentially all breeding attempts that produced an egg were detected. Nests were monitored visually and nesting phenology was inferred based on parental behavior, or where possible, observations of eggs and chicks, including regular nest entries at most nests. Starting in 2012, webcams were installed at a subset of remote nests. Additional details on the collection of daily condor data are available through the U.S. Fish and Wildlife Service (https://ecos.fws.gov/ecp/species/8193). Data are summarized as described in the associated paper, “Anthropogenic threats and young age skew lower fertility in the first two decades of reintroduction for critically endang..., Data and code compiled in R.R Core Team (2022). R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. URL https://www.R-project.org/.

本研究针对从野外完全灭绝后恢复种群的极危物种加州神鹫（Gymnogyps californianus）的繁殖率开展首次全面评估，分析了1999年至2018年共计20年的加州南部与中部神鹫种群监测数据。研究发现多类人为威胁会影响其繁殖率：（1）雌性神鹫的沿海空间利用行为与更低的孵化概率相关，推测原因是海洋哺乳动物觅食行为及伴随的DDE暴露；（2）在2007年实施垃圾管理政策前，雏鸟摄入垃圾会降低其出飞概率；（3）育雏期间亲鸟全部死亡均会导致雏鸟或早期出飞个体死亡，且多数亲鸟死亡原因为铅中毒。本研究还检测到针对神鹫的复杂个体管理措施对繁殖率的多项影响，此类管理包括持续放归圈育个体以及包括铅中毒治疗在内的健康干预手段。Recrui...，监测工作以近乎每日的频次开展，通过目视或遥测信号定位每只个体。2002年起在南部种群、2008年起在中部种群中，增设投喂站的摄像头监测并将相关记录纳入数据集。鉴于本研究的高强度监测方案，我们认为几乎所有产蛋繁殖尝试均被成功记录。巢穴通过目视监测，繁殖物候可通过亲鸟行为推断，或在可行情况下通过对鸟蛋与雏鸟的观测确定，多数巢穴会定期开展检查。2012年起，我们在部分偏远巢穴安装了网络摄像头。每日神鹫监测数据的更多细节可通过美国鱼类及野生动物管理局获取（https://ecos.fws.gov/ecp/species/8193）。数据集与代码的整理方式如相关论文《人为威胁与低龄个体导致极危物种种群重新引入前二十年的繁殖率偏低》（原文标题截断）所述。数据集与代码均基于R语言编译（R Core Team, 2022）。R：用于统计计算的语言与环境。奥地利维也纳R统计计算基金会，网址https://www.R-project.org/。