Atlantic Offshore Seabird Dataset Catalog

Several bureaus within the Department of Interior compiled available information from seabird observation datasets from the Atlantic Outer Continental Shelf into a single database, with the goal of conducting research and informing coastal and offshore planning activities. The cooperators were the Bureau of Ocean Energy Management's (BOEM) Environmental Studies Program (http://www.boem.gov/Environmental-Stewardship/Environmental-Studies/Environmental-Studies.aspx), the U.S. Fish and Wildlife Service's (USFWS) Division of Migratory Bird Management (http://www.fws.gov/migratorybirds/) and the U.S. Geological Survey's (USGS) Patuxent Wildlife Research Center (http://www.pwrc.usgs.gov). The resulting product is the Atlantic Offshore Seabird Dataset Catalog, which characterizes the survey effort and bird observations that have been collected across space and time. Currently, the database contains ~60 datasets from 1906-2009 with over 260,000 records of seabird observations. Data will initially be provided as summary web mapping services, with web feature services (for downloading and looking at single-species data) at the linkage given elsewhere in this document. USAGE: Seabirds provide unique challenges even when using estimation techniques to sample populations (e.g., Tasker et al. 1984, Spear et al. 1992). To date, there has been little consistency among survey designs. Surveys have varied by the type of vessel from which they are conducted (ship, plane), the methodology that counts are made, the width of the area being counted, and equipment used, among many other differences. Under such circumstances, comparing results and making inferences can be difficult. Because these estimates of effort-adjusted counts do not account for detection probability, they are likely biased by factors that affect this parameter such as weather, survey method, observer, or other environmental variables (MacKenzie et al. 2006). Such results may be considered naïve in that they do not account for factors that can affect the ability to detect an animal. Furthermore, these results contain data collected over a 30 year period without regard for any long term temporal changes that may have occurred with species or the environment. Further analysis is necessary to determine if such changes have occurred with any species. While it is possible to separate data collected recently from historical (>20 years old) datasets, the amount of recent data is limited and therefore maps showing only these data may be limited spatially. Finally, effort calculations do not account for survey width, while normally static during a survey, can be reduced during certain conditions and does vary by survey method, especially boat vs. plan surveys. The vast majority of survey data collected offshore U.S. Atlantic waters were collected using similar techniques and so effort data will not be greatly affected by such discrepancies. Still, such differences do exist and were not accounted for; therefore, this estimate of survey effort is a rough surrogate for effort. Consequently, the effort-adjusted counts will also be affected by differences in survey methodology and should be considered only roughly offset by effort.

美国内政部下属多个局将大西洋外大陆架（Atlantic Outer Continental Shelf）的海鸟观测数据集的现有信息整合至单一数据库，旨在开展相关研究并为海岸与近海规划活动提供决策参考。本数据集的合作方包括海洋能源管理局（Bureau of Ocean Energy Management, BOEM）环境研究项目（http://www.boem.gov/Environmental-Stewardship/Environmental-Studies/Environmental-Studies.aspx）、美国鱼类及野生动物管理局（U.S. Fish and Wildlife Service, USFWS）迁徙鸟类管理司（http://www.fws.gov/migratorybirds/）以及美国地质调查局（U.S. Geological Survey, USGS）帕塔克森特野生动物研究中心（http://www.pwrc.usgs.gov）。

最终产出的成果为大西洋近海海鸟数据集目录（Atlantic Offshore Seabird Dataset Catalog），该目录对跨时空收集的海鸟调查工作量与观测记录进行了特征描述。目前，该数据库收录了1906年至2009年间的约60套数据集，涵盖超过26万条海鸟观测记录。

数据初期将以汇总型网络地图服务的形式提供，而用于下载及查看单物种种群数据的网络要素服务（web feature services）将通过本文档其他位置给出的链接获取。

**使用说明**：即便采用种群采样估计技术，海鸟调查仍面临独特的挑战（例如Tasker等1984年、Spear等1992年的研究）。截至目前，不同海鸟调查的设计方案鲜有统一标准。调查方式存在诸多差异，包括观测载体类型（船舶、飞机）、计数方法、统计区域宽度以及所用仪器设备等多个方面。在此情形下，对调查结果进行比较并作出推论往往难度较大。由于这些经调查工作量校正的计数估计值未考虑检测概率，其结果可能受影响该参数的各类因素偏倚，例如天气状况、调查方法、观测者或其他环境变量（MacKenzie等2006年的研究）。

此类结果可被视为"朴素估计"，因为它们未考虑所有可能影响动物检测成功率的因素。此外，该数据集包含了长达30年的观测数据，未考虑物种或环境可能发生的长期时间序列变化。需开展进一步分析，以明确是否有物种出现了此类变化。尽管可以将近期收集的数据与历史（距今20年以上）数据集进行分离，但近期数据的体量有限，因此仅基于近期数据生成的地图在空间覆盖范围上可能存在局限。

最后，调查工作量的计算未考虑调查宽度——调查宽度通常在单次调查中保持固定，但在特定条件下可能缩小，且不同调查方法（尤其是船舶调查与飞机调查）的调查宽度存在差异。美国大西洋海域近海收集的绝大多数调查数据采用了相似的技术手段，因此调查工作量数据受此类差异的影响相对有限。尽管如此，此类差异确实存在且未被纳入校正范畴，因此本次的调查工作量估计值仅为调查工作量的粗略替代指标。因此，经调查工作量校正的计数结果同样会受调查方法差异的影响，仅可视为经调查工作量粗略校正后的结果。