Birds of the valleys of the Tom River tributaries (Tomsk oblast)

Our study site is situated in the southern part of Tomsk oblast, in the sub-taiga zone, between the Kuznetsk forest-steppe, mountain forests of the Kuznetsk Alatau spurs and the southern taiga of West Siberia. The sub-taiga zone is a point of interest of zoo-geographers as it is a transitional area from the taiga animal population to the forest-steppe one. The aim of our research was to reveal the modern species composition and the quantity (abundance, number) of birds in the valleys of the Tom River tributaries, as well as the dynamics of these parameters during the last 40 years. We have studied avifauna and bird populations of the valleys of the Tom River tributaries since 1958. We examined seven rivers with the mouth not farther than 35 km from Tomsk. For four river valleys, we studied summer population of birds during the periods from 20 May to 25 July of 2008 and 2010. Our transects covered 6 types of habitats: dark coniferous forests, pine forests, mixed forests, small-leaved forests, meadows with bushes and settlements. Totally, 106 transects with the general length of 800 km were recorded. In other valleys of the Tom River tributaries, we analyzed bird species composition and their presence. 272 bird species were revealed in the region under investigation, 80% of them nest there and the rest use the territory for migrations and wintering. The highest population density is in settlements. Complexes of small-leaved forests and meadows with bushes prevail in this ecosystem among natural habitats. Species diversity is higher in dark-coniferous forests. In settlement landscape, the major species diversity is noticed at the periphery of the city. Minimal density of bird populations and species diversity are typical of pine forests. On the study site, our investigation revealed the stay of 31 out of 41 bird species listed in the Red Book of Tomsk oblast. 22 species of them are nesting, 8 are migrating or occasionally flying across and one is wintering. Since the publication of the last ornithofaunistic report (1978), 13 new bird species have been found in the region under investigation: circaetus ferax, Phalaropus fulicarius, Merops apiaster, Riparia diluta, Parus caeruleus, Turdus obscurus, Trudus merula, Anthus rubescens, Anthus spinoletta, Acrocephalus palustris, Locustella fluviatilis, Acanthis hornemanni and corvus dauuricus. Sturnus vulgaris, Emberiza aureola, Motacilla flava, Anthus richardi, Cannabina cannabina. Milvus migrans, Acrocephalus dumetorum, chloris chloris and Fringilla coelebs show a decrease in populations. The quantity of corvus cornix in Tomsk in winter season significantly increased compared to the end of the XX century, meanwhile we saw a definitely decreasing winter abundance of corvus corone.

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