Cygnus cygnus Haliaeetus albiculla

         Besides its permanent components biofilota comprises also temporal or seasonal ones. Ornithological fauna comprises the highest ratio of the latter. Consequently, the wellbeing of subregional biodiversity of birds to a considerable degree depends on the environmental quality of other, often very remote areas, at which part of their life cycle passes.
         The most vulnerable are nesting places of rookery birds or waterfowl the majority of which is located at the Iona Island in the Sea of Okhotsk and at the remote islands of Peter the Great Bay. Wintering grounds of big birds of prey and swimming birds are also highly important (southern part of the Far-Eastern ecoregion) along with compact migration routes passing through the sea coast and valleys of large rivers.