We conducted ground-based surveys at 589 randomly selected 16-ha plots on the Yukon-Kuskokwim Delta, Alaska during 2015-2016. The plots were selected using a stratified random sampling plan in an area of 35,769 square km divided into 8 physiographic strata. The population totals from the stratified random design estimators were adjusted using detection ratios derived with a double sampling protocol (Bart and Earnst 2002) on a subset of plots in Alaska.The subset of plots used for double sampling included 17 study plots on the Yukon Delta National Wildlife Refuge (9 plots in 2001-2002 [McCaffery et al. 2012] and 8 plots in 2016), and 33 plots located on the North Slope of Alaska (Utqiaġvik [6 plots, 2014–2015], the Colville River [20 plots, 1998–2001; Bart and Johnston 2012, Bart et al. 2013], and the Canning River [7 plots, 2002, 2004; Brown et al. 2007]).