Russian Boreal Forest Avifauna
Recent bird studies across the boreal forest in Russia show that bird abundance is lowest in the center of the continent. About 4 out of 5 birds in the boreal forest are migratory. The migrants in the eastern end mostly winter in the tropics, while those in the western end winter in temperate areas, such as around the Mediterranean.
Geographic features south of the boreal forest probably cause these patterns of bird diversity. At the western end, high mountains and deserts, such as the Sahara and the Himalayas, deter migrants from reaching tropical wintering areas, whereas access to the tropics through eastern Asia is largely unimpeded.
In North America, the eastern boreal forest (New England, Maine, Great Lakes area) is more similar in climate, bird abundance, and migration strategy to the Russian far east than it is to Scandinavia, which is the traditional area for comparative studies.
This article summarizes the information in this scientific paper:
Greenberg, R.S., Kozlenko, A., Etterson, M. and Dietsch, T. 2008. Patterns of density, diversity, and the distribution of migratory strategies in the Russian boreal forest avifauna. Journal of Biogeography, 35(11): 2049-2060.