In 2019 a pilot study was conducted to determine the feasibility of using distance sampling to estimate density and population size of goose and eider nests on the Yukon-Kuskokwim Delta (YKD). Distance sampling (Buckland et al. 2001) is a common and well-understood method to estimate wildlife population size or density, especially for sparse and hard-to-detect populations. A main advantage of distance sampling is that it accounts for imperfect detection and gives precise estimates for a given level of effort relative to other methods. The objectives for the pilot project in 2019 was to (1) determine if distance sampling is feasible on the YKD, (2) determine what aspects of the field protocol need to be changed or clarified, (3) determine the amount of effort needed to collect distance sampling data on the YKD, and (4) obtain distance sampling data from a variety of field crews and plots. We did not expect to collect enough data in this field season to provide reasonable estimates of populations. We did, however, get enough data to estimate the shape of a detection function for all nests. These data collected during the pilot project, in combination with nest plot data and additional assumptions, was used in a Master’s graduate student thesis to simulate various survey designs using distance sampling to estimate spectacled eider and three species of goose nest population density. Products associated with this project include: various reports, the field protocol for the 2019 field season, R code used for simulations, geographic locations of the distance sampling transects, and data on transect search time. Nest data collected during this pilot is found in the main nest cards data file, with “PLOTTYPE” = “D”.
