Avian Habitat Data; Seward Peninsula, Alaska, 2012

This data product contains avian habitat data collected on the Seward Peninsula, Alaska, USA, during 21 May – 10 June 2012. We conducted replicated 10-min surveys at 111 points located along 9 transects occurring over gradients of physical and biotic habitat conditions and recorded observations of individual birds identified to species. Survey points, or sites, were located approximately 500 m apart and observations of birds were limited to a maximum distance of 250 m to prevent double counting. We visited each survey site 2–3 times and assumed community closure within the survey period. Mean interval (±SD) between site-specific surveys was 5.8 ± 2.4 days. We measured 13 vegetative characteristics at 10 subsampling points associated with each bird survey location during 26 June – 11 July 2012. Five subsampling plots were located along each of two 20-m transects with random orientation (0–359 degrees). One transect originated at the bird survey point, and the other at a point selected randomly within 250 m of the bird survey point. At each subsampling point, we estimated overlapping coverages within six vegetation classes, including alder (Alnus spp.), dwarf birch (Betula spp.), ericaceous shrubs (e.g., Empetrum, Vaccinium spp.), herbaceous, lichen (e.g., Cladonia spp.), and willow (Salix spp.) using a 0.5-m2 quadrat frame, and recorded the height of the tallest plant of each type within the sampling frame. We recorded visual obstruction (VOR), an index of vegetation of height and density, at each subsampling point measured from a distance of 2 m and at a height of 0.5 m. Analyses of these data are published in: McNew, L. B., and C. M. Handel. 2015. Evaluating species richness: biased ecological inference results from spatial heterogeneity in species detection probabilities. Ecological Applications 25: in press. http://dx.doi.org/10.1890/14-1248.1