Population vulnerability of marine birds within the California Current System

Six metrics were used to determine Population Vulnerability: global population size, annual occurrence in the California Current System (CCS), percent of the population present in the CCS, threat status, breeding score, and annual adult survival. Global Population size (POP)—to determine population size estimates for each species we gathered information tabulated by American Bird Conservancy, Birdlife International, and other primary sources. Proportion of Population in CCS (CCSpop)—for each species, we generated the population size within the CCS by averaging region-wide population estimates, or by combining state estimates for California, Oregon, and Washington for each species (if estimates were not available for a region or state, “NA” was recorded in place of a value) and then dividing the CCSpop value by the estimated global population size (POP) to yield the percentage of the population occurring in the CCS. Annual Occurrence in the CCS (AO)—for each species, we estimated the number of months per year within the CCS and binned this estimate into three categories: 1–4 months, 5–8 months, or 9–12 months. Threat Status (TS)—for each species, we used the International Union for Conservation of Nature (IUCN) species threat status (IUCN 2014) and the U.S. Fish and Wildlife national threat status lists (USFWS 2014) to determine TS values for each species. If available, we also evaluated threat status values from state and international agencies. Breeding Score (BR)—we determined the degree to which a species breeds and feeds its young in the CCS according to 3 categories: breeds in the CCS, may breed in the CCS, or does not breed in the CCS. Adult Survival (AS)—for each species, we referenced information to estimate adult annual survival, because adult survival among marine birds in general is the most important demographic factor that can affect population growth rate and therefore inform vulnerability. These data support the following publication: Adams, J., Kelsey, E.C., Felis J.J., and Pereksta, D.M., 2016, Collision and displacement vulnerability among marine birds of the California Current System associated with offshore wind energy infrastructure: U.S. Geological Survey Open-File Report 2016-1154, 116 p., http://dx.doi.org/10.3133/ofr20161154.本研究采用六项指标评估种群脆弱性：全球种群规模、加利福尼亚洋流系统（California Current System，以下简称CCS）年度出现频次、种群在CCS中的占比、威胁等级、繁殖评分以及成年个体年存活率。 全球种群规模（POP）：为获取各物种种群规模估算值，我们收集了由美国鸟类保护协会（American Bird Conservancy）、国际鸟类联盟（Birdlife International）及其他权威来源制表汇总的相关数据。 种群在CCS中的占比（CCSpop）：针对每个物种，我们通过两种方式计算其在CCS内的种群规模：一是对全区域种群估算值取平均，二是合并加利福尼亚州、俄勒冈州与华盛顿州的州级种群估算值；若某区域或州无对应估算值，则以"NA"填充。随后将所得CCS内种群规模除以全球种群规模（POP），即可得到该物种种群在CCS中的占比百分比。 CCS年度出现频次（AO）：针对每个物种，我们估算其每年在CCS内停留的月数，并将该估算结果划分为三类：1–4个月、5–8个月或9–12个月。 威胁等级（TS）：针对每个物种，我们参考国际自然保护联盟（International Union for Conservation of Nature, IUCN）2014年发布的物种威胁等级，以及美国鱼类及野生动物管理局（U.S. Fish and Wildlife）2014年的国家级威胁等级列表，确定各物种的TS值；若有可用数据，我们同时会评估来自各州及国际机构的威胁等级信息。 繁殖评分（BR）：我们依据三类标准判定物种在CCS内繁殖及育幼的程度：在CCS内繁殖、可能在CCS内繁殖，以及不在CCS内繁殖。 成年个体年存活率（AS）：针对每个物种，我们参考相关数据估算其成年个体年存活率。总体而言，海鸟的成年存活率是影响种群增长速率的关键种群统计参数，因此可用于评估物种脆弱性。 本数据集支撑以下出版物：Adams, J.、Kelsey, E.C.、Felis J.J. 及 Pereksta, D.M.，2016年，《与离岸风电基础设施相关的加利福尼亚洋流系统海鸟碰撞及驱离脆弱性》：美国地质调查局公开文件报告2016-1154，共116页，http://dx.doi.org/10.3133/ofr20161154。