House (Passer domesticus) and Tree (P. montanus) Sparrows (Passeriformes, Passeridae) in the Lower Ob River Basin and Yamal Peninsula: Specific Features of the Distribution of Sparrows in Northwestern Siberia

Resumo

House and tree sparrows were common in cities and towns of the Lower Ob River basin down to the mouth in the 1970s–1980s. Currently, the house sparrow has spread in the localities of the middle and northern Yamal areas, whereas the tree sparrow has almost disappeared from the Lower Ob River basin. The house sparrow has moved to the Subarctic owing to the presence of localities with residential houses and warm shelters for vehicles and equipment, as well as houses near the oil and gas drill sites. This species reproduces during the same periods as in the temperate latitudes, annually brings two clutches, has an extended molting period, and migrates only in spring. The tree sparrow has similar ecological characteristics but prefers old wooden buildings. The southward shift of the distribution range of the tree sparrow is most likely associated with a decrease in the population.