Data from: Geographic variation and environmental correlates of apparent survival rates in adult tree swallows Tachycineta bicolor

Determining demographic rates in wild animal populations and understanding why rates vary are important challenges in population ecology and conservation. Whereas reproductive success is reported frequently for many songbird species, there are relatively few corresponding estimates of annual survival for widespread populations of the same migratory species. We incorporated mark-recapture data into Cormack-Jolly-Seber models to estimate annual apparent survival and recapture rates of adult male and female tree swallows Tachycineta bicolor in eight local breeding populations across North America for periods of 7-33 years. We found strong site-specific and annual variation in apparent survival rates of adult swallows, and evidence of higher survival or site fidelity among males than females. There were no strong associations between putative overwintering region and survival. Strength and patterns of winter climate-apparent survival relationships varied across four sites monitored for >15 years; at one site, spring pond conditions, local spring precipitation and, to a lesser extent, winter North Atlantic Oscillation Index were credible predictors of annual apparent survival. Further work is needed to evaluate how survival is related to environmental conditions throughout the annual cycle and how these factors affect population dynamics of swallows and related species of conservation concern.

探明野生动物种群的种群统计参数并解析参数差异的成因，是种群生态学与保护生物学领域的重要研究课题。尽管诸多鸣禽物种的繁殖成功率已有大量研究报道，但针对同一迁徙类群的广布种群，其年存活率的对应估算却相对匮乏。我们将标记重捕（mark-recapture）数据纳入Cormack-Jolly-Seber模型（Cormack-Jolly-Seber Model），以估算北美8个本地繁殖种群中成年雄性与雌性树燕（Tachycineta bicolor）的年表观存活率与重捕率，研究周期跨度为7至33年。研究发现，成年树燕的表观存活率存在显著的位点特异性与年度差异，且有证据表明雄性个体的存活率或栖地保真度高于雌性。推测的越冬区域与存活率之间未发现显著关联。在监测时长超过15年的4个位点中，冬季气候与表观存活率的关联强度及模式存在差异；其中一个位点的春季池塘状况、当地春季降水量，以及程度较弱的冬季北大西洋涛动指数（North Atlantic Oscillation Index），均可作为年表观存活率的可靠预测因子。未来仍需开展进一步研究，以明确存活率与全年环境条件的关联机制，以及这些因素如何影响树燕及其相关受保护物种的种群动态。