Arctic Shorebirds in North America: A Decade of Monitoring

4. NORTH SLOPE OF ALASKA

37 Abstract. We used a combination of ground and aerial surveys to characterize the abundance and distribution of shorebirds and other birds on the North Slope of Alaska. The double sampling method, which we used for the ground surveys, is described in Bart et al. (chapter 2, this volume). The aerial surveys were conducted during 1992–2005 and covered most of the study area. We present numbers recorded, estimated densities and population sizes, and habitat relationships for shorebirds and other species. Most species occurred in higher density, and had much larger populations, in the National Petroleum Reserve–Alaska than west of the Colville River. The most abundant shorebirds were Semipalmated Sandpipers and Pectoral Sandpipers, with estimated populations of about 1.2 million birds each; and Long-billed Dowitchers, Red and Red-necked Phalaropes, and Dunlin, with estimated populations of 500,000–700,000 each. The most abundant waterfowl were Northern Pintails, Greater White-fronted Geese, and Longtailed Ducks, with estimated populations of 200,000–300,000 each. Glaucous and Sabine’s Gulls, Arctic Terns, and Parasitic and Long-tailed Jaegers each had estimated populations of about 30,000–100,000. Lapland Longspurs, Savannah Sparrows, and Willow Ptarmigan were the most common landbirds, with estimated populations of about 1 million each. All but a few species were most common in wetlands and least common in uplands. Key Words: Alaska, landbirds, North Slope, population estimates, shorebirds, surveys, waterbirds, waterfowl. CHAPTER FOUR North Slope of Alaska Jonathan Bart, Stephen Brown, Brad A. Andres, Robert Platte, and Ann Manning Bart, J., S. Brown, B. A. Andres, R. Platte, and A. Manning. 2012. North Slope of Alaska. Pp. 37–96 in J. Bart and V. Johnston (editors). Arctic shorebirds in North America: a decade of monitoring. Studies in Avian Biology (no. 44), University of California Press, Berkeley, CA. T he North Slope of Alaska is a major nesting area for a wide variety of bird species, including shorebirds, waterfowl, gulls and terns, and landbirds (National Research Council 2003, Johnson et al. 2007). However, there has never been an analysis of the density of these species across the entire range of habitats in the region. Previous studies have provided either descriptions of the ranges of these species within the region or densities for some species in some parts of this larger area (Mallek et al. 2004, Larned et al. 2005, Brown et al. 2007, Johnson et al. 2007, STUDIES IN AVIAN BIOLOGY NO. 44 Bart and Johnston 38 unpublished U.S. Fish and Wildlife Service reports). This monograph provides the results of the first such analysis, for all arctic-nesting birds that occur on the North Slope. The primary goals of this study were (1) to collate and present results from bird surveys conducted during many years, and provide graphic displays of bird numbers recorded; (2) to estimate the density of each species, and calculate estimates of total population size in the study area; and (3) to examine interrelationships among habitat types and nesting densities by species to determine which habitats are most important for each species. Measurements of density and total population are important for understanding both the biology of these species and the relative importance of the region for their global populations. Many conservation systems use the relative contribution of a specific area to total population size to determine importance for conservation. For example, the Western Hemisphere Shorebird Reserve Network (WHSRN; www.whsrn.org) and the Ramsar Convention on Wetlands of International Importance, especially as waterfowl habitat (Ramsar Convention; www.ramsar.org), both use the percentages of a flyway population as a conservation threshold. Similar criteria have been developed by the Important Bird Areas Program of Birdlife International (www.birdlife.org/action/ science/sites). All of these programs rely on having both accurate overall population size estimates for each species and estimates of the proportion of the population using particular areas of interest. The development of accurate population estimates for the North Slope region of Alaska will contribute significantly to both of these goals by providing the first regional population estimates and by providing a context against which to evaluate total population size estimates published for various species. Major threats to breeding birds in the North Slope region include oil and gas development and climate change. Understanding the current densities of breeding birds in the region is a prerequisite to determining impacts of any future changes in the wetland and tundra habitats supporting these birds. Oil and gas development have been under way on...