HOUSE SPARROW (PASSER DOMESTICUS) AND TREE SPARROW (PASSER MONTANUS) (PASSERIFORMES, PASSERIDAE) IN THE LOWER OB RIVER BASIN AND YAMAL PENINSULA: SPECIFIC FEATURES OF DISTRIBUTION OF THE SPARROWS IN THE NORTH OF WESTERN SIBERIA

摘要

In 1970-1980, house sparrows and tree sparrows were common in cities and towns of the Lower Ob River basin up to the mouth of the river. Presently, house sparrows have penetrated to settlements of the middle and northern areas of Yamal, but tree sparrows from the settlements of the Lower Ob River basin have disappeared. House sparrow moves to the Subarctic due to the presence of settlements with warm hangars for techniques and separate wellsites with residential houses. The reproduction of these birds proceeds in the terms common with those in the temperate latitides. They retain the ability to have two clutches, molting seasons are extended, and only the spring migratory state is formed. Tree sparrow has ecological characteristics similar to those in house sparrow, but prefers old wooden buildings. A shift of the boundaries of tree sparrow's range to the south is suggested to be due to a reduction in the numbers of its population.