Russian Empire Bolsheviks followed in 1918. The administrative boundaries of European Russia, apart from Finland and its portion of Poland, coincided approximately with the natural limits of the East-European plains. In the North it met the Arctic Ocean. Novaya Zemlya and the Kolguyev and Vaygach Islands also belonged to it, but the Kara Sea was referred to Siberia. To the East it had the Asiatic territories of the Empire, Siberia and the Kyrgyz steppes, from both of which it was separated by the Ural Mountains, the Ural River and the Caspian Sea — the administrative boundary, however, partly extending into Asia on
Severnaya Zemlya to a survey of prior observations by De Korte, Volkov, and Gavrilo, thirty-two bird species have been observed on Severnaya Zemlya, 17 of which are known to breed on the islands. Eight species are widespread across the archipelago: five of which are colonial seabirds: little auk ("Alle alle"), black-legged kittiwake ("Rissa tridactyla"), black guillemot ("Cepphus grylle"), ivory gull ("Pagophila eburnea"), and glaucous gull ("Larus hyperboreus"); and three species of tundra bird: the snow bunting ("Plectrophenax nivalis"), purple sandpiper ("Calidris maritima"), and brent goose ("Branta bernicla"). The most common mammal on Severnaya Zemlya is the collared lemming ("Dicrostonyx torquatus"), also known