Avian population sizes fluctuate and change over vast spatial scales, but the mechanistic underpinnings remain poorly understood. A key question is whether spatial and annual variation in avian population dynamics is driven primarily by variation in breeding season recruitment or by variation in overwinter survival. We present a method using large‐scale volunteer‐collected data from project eBird to develop species‐specific indices of net population change as proxies for survival and recruitment, based on twice‐annual, rangewide snapshots of relative abundance in spring and fall. We demonstrate the use of these indices by examining spatially explicit annual variation in survival and recruitment in two well‐surveyed nonmigratory North American species, Carolina wren Thryothorus ludovicianus and northern cardinal Cardinalis cardinalis. We show that, while interannual variation in both survival and recruitment is slight for northern cardinal, eBird abundance data reveal strong and geographically coherent signals of interannual variation in the overwinter survival of Carolina wren. As predicted, variation in wintertime survival dominates overall interannual population fluctuations of wrens and is correlated with winter temperature and snowfall in the northeastern United States, but not the southern United States. This study demonstrates the potential of participatory science (also known as citizen science) datasets like eBird for inferring variation in demographic rates and introduces a new complementary approach towards illuminating the macrodemography of North American birds at comprehensive continental extents.

中文翻译：

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通过参与式科学揭示北美鸟类种群的季节性宏观种群


鸟类种群规模在广阔的空间尺度上波动和变化，但对其机制基础仍然知之甚少。一个关键问题是鸟类种群动态的空间和年度变化是主要由繁殖季节补充的变化还是由越冬生存率的变化驱动的。我们提出了一种方法，使用来自 eBird 项目的大规模志愿者收集的数据，根据春季和秋季每年两次的范围内相对丰度快照，开发物种特异性的净种群变化指数，作为生存和招募的代理。我们通过检查两个经过充分调查的非迁徙北美物种（卡罗莱纳鹪鹩 Thryothorus ludovicianus 和北方红衣主教红衣主教）在生存和招募方面的空间明确年度变化来证明这些指数的使用。我们表明，虽然北方红雀的存活率和补充年际变化很小，但 eBird 丰度数据揭示了卡罗来纳鹪鹩越冬存活率年际变化的强烈且地理连贯的信号。正如预测的那样，冬季存活率的变化在鹪鹩的整体年际种群波动中占主导地位，并且与美国东北部的冬季温度和降雪有关，但与美国南部无关。这项研究展示了像 eBird 这样的参与式科学（也称为公民科学）数据集在推断人口统计率变化方面的潜力，并引入了一种新的补充方法来阐明北美鸟类在综合大陆范围内的宏观人口统计学。