| Summary: | The warming of the Arctic, especially in the Eurasian sector, has been pronounced since the 1920s. The tundra moves into the arctic desert, the taiga into the tundra, and along with this the mammals, birds and plants extend northward. Study of these changes in zoogeographical boundaries by Soviet scientists shows that some birds have extended their ranges up to 130 mi northward, the willow warbler, meadow pipit, fieldfare and willow ptarmigan to 69° 50' N on Vaygach Island, 74° N Novaya Zemlya. From more southerly ranges the house sparrow has extended from 61° to 70° N, the chaffinch and rook 700 km from Krasnoyarsk to Komsa, the black woodpecker, coal tit, whooper swan and merganser 200-400 km in the Yenisey taiga. The fieldfare, eastern hermit thrush and robin are now established in Greenland, the gadwall in southern Alaska.
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