Data Supporting the Inventory of Breeding Birds in Aniakchak National Monument and Preserve, Alaska, 2008

The survey area selection process employed a stratified random sampling design based on ecological subsections. We identified potential sampling units by using an existing Alaska-wide Geographic Information System (GIS) grid composed of 10-km x 10-km (6.2-mi x 6.2-mi) plots (Ruthrauff et al. 2007).

We used point count and distance sampling methodologies (point transects; Fancy and Sauer 2002, Buckland et al. 2001) to survey birds, following protocols that have been standardized for Alaska (Tibbitts et al. 2005, Handel and Cady 2004). All bird species were recorded and enumerated at each sampling point. Survey methods incorporated detection probability through distance sampling (Buckland et al. 2001) and recording time interval of first detection (Farnsworth et al. 2002). Survey points were placed across major landscape gradients such as coastlines, river valleys, and ridgelines. Sample points were located at least 500 m apart to avoid double-counting individual birds. In addition, teams recorded the approximate location and identity of any previously undetected species encountered during travel between survey points.

We recorded topographic data at sample points, including elevation, slope, and aspect, and all points were georeferenced using a GPS unit. Point-count survey crews classified habitat within a 150-m radius of the sample point to the Viereck classification system (Viereck et al. 1992). When more than 1 habitat type existed within the circle, the percent of the circle occupied by each habitat type was recorded. Crews took digital photographs toward each cardinal direction to supplement habitat data collected at each sample point.

We identified species of conservation concern within Aniakchak National Monument and Preserve as defined by one of five conservation organizations: Audubon Alaska (Stenhouse and Senner 2005), Partners in Flight (Rich et al. 2004), U.S. Fish and Wildlife Service (U.S. Fish and Wildlife Service 2002), Alaska Shorebird Group (Alaska Shorebird Group 2008), and Boreal Partners in Flight (Boreal Partners in Flight Working Group 1999).