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Observer-specific population indices for the USFWS Region Migratory Bird Management Arctic Coastal Plain study area. The survey consists of low-level aerial observations of waterfowl on a stratified strip transect design. The resulting data frame is several indices separated by observer and calculated using a standard ratio estimator. These data are output from the R package AKaerial and are also available within that package, see https://github.com/USFWS/AKaerial. The data used to produce these estimates contain known errors. Many but not all of these errors are corrected within the R package AKaerial. These data are presented for historical purposes only. See https://github.com/USFWS/ACP-Mapping and comments within...
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The roselaari subspecies of Red Knot is one of the rarest shorebird populations breeding in North America, based on a the current population size estimate of 17,000 individuals (Carmona et al 2013). As a result of suspected declines,the roselaari subspecies has been designated as threatened by the Committee on the Status of Endangered Wildlife in Canada and was petitioned for listing under the U.S. Endangered Species Act. The U.S. Fish and Wildlife Service’s decision to not conduct a full status review for listing was based on the lack of substantial information identifying threats and population trends (USFWS 2011). The apparent low population size coupled with the scarcity of information on many demographic and...
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Combined population indices for the USFWS Region Migratory Bird Management Arctic Coastal Plain study area. The survey consists of low-level aerial observations of waterfowl on a stratified strip transect design. The resulting data frame is several indices combined over observers (or single observer in years where estimates were not combined) and calculated using a standard ratio estimator. These data are output from the R package AKaerial and are also available within that package, see https://github.com/USFWS/AKaerial. The data used to produce these estimates contain known errors. Many but not all of these errors are corrected within the R package AKaerial. These data are presented for historical purposes only....
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The Pacific Flyway Winter Brant Survey (WBS) has been conducted annually since 1981 as part of a cooperative effort by the U.S. Fish and Wildlife Service, Canadian Wildlife Service, Mexico, and the Pacific U.S. states, to estimate the abundance of the Pacific black brant (Branta bernicla nigricans) in their principal wintering areas along the Pacific Coast (in Baja, Mexico, California, Oregon, Washington, British Columbia, and Alaska). The survey is conducted each winter in January-February by a composite of ground and aerial crews, with the Alaska portion being conducted by the Alaska Region of USFWS Migratory Bird Management. The primary objective of the Alaska survey component is to provide an annual index of...