Broad-scale avian surveys have been attempted within North America with mixed results. Arid regions, such as the Great Basin, are often poorly sampled because of the vastness of the region, inacessibilty of sites, and few ornithologist. In addition, extreme variability in wetland habitat conditions present special problems for conducting censuses of species inhabiting these areas. We examined these issues in assessing multi-scale shorebird (order: Charadriiformes) censuses conducted the western Great Basin from 1992-1997. On ground surveys, we recorded 31 species of shorebirds, but were unable to accurately estimate population size. Conversely, on aerial surveys we were able to estimate regional abundance of some shorebirds, but were unable to determined species diversity. Acrial surveys of three large alkali lakcs in Oregon (Goose, Summer, and abert Lakes) revealed > 300,000 shorebirds in one year of this study, of which 67% were American Avocets (Recurvirostra americana) and 30% phalaropes (Phalaropus spp.). These lakes clearly meet Western Hemisphere Shorebird Reserve Network guidelines for designation as important shorebirds sites. Based upon simulations of our monitoring effort and the magnitude and variation of numbers of American Avocets, detection of 5-10% negative declines in population of these birds would take a minimum of 7-23 years comparable effort. We conclude that a combination of ground and aerial surveys must be conducted at multiple sites and years and over a large region to obtain an accurate picture of the diversity, abundance, and trends of shorebirds in the western Great Basin.
Additional publication details
Monitoring species richness and abundance of shorebirds in the western Great Basin