The presented data on the numbers of protected animals are estimates. The data come from the regional directorates of environmental protection, which obtain them, among others, from the organizational units of the State Forests or national parks and on the basis of natural inventories from previous years and literature data. The data are not supported by fieldwork performed according to a single methodology, but are collected cyclically once a year from the same sources.The exception is the bison, which numbers are given according to data from the "European Bison Pedigree Book". Suorce: Data of the General Directorate for Environmental Protection.