Combined population indices of ducks and loons (YKD) and geese and swans (YKG) for the USFWS Region Migratory Bird Management Alaska Yukon-Kuskokwim Delta Aerial Survey study area in a combined csv format. The survey consists of low-level aerial observations of waterfowl on a stratified strip transect design. The resulting data frame is several indices combined over observers (or single observer in years where estimates were not combined) and calculated using a standard ratio estimator. These data are output from the R package AKaerial and are also available within that package, see https://github.com/USFWS/AKaerial.
