Abstract <p>This article is the third publication in which we methodically substantiate the methods for use of bird ring-recovery data for definition of the population parameters of individual species, the demographic statuses of their populations, and calculation of the rational harvest rates in huntable bird species. To increase the application of ring-recovery data for rational (sustainable) use of waterfowl resources, we propose a new method of calculation of the hunting bag size. As huntable objects it is possible to use only those species that are not included in various levels of Red Data Books and those where the demographic status of a species allows hunting. The proposed calculation includes data on the annual mortality rate of different waterfowl species and age cohorts, obtained from ring-recovery data together with information on the total species numbers taken from surveys and expert assessments. In addition, ring-recovery data allow calculation of the waterfowl hunting bag size for individual regions of Russia for birds that winter in Europe and breed in the northern parts of European Russia and Western Siberia. The proposed method directed to make the hunting bag calculation more rational is recommended for use instead of the normally used arbitrary and generally intuitive approach to this very important problem.</p>