The Red-flanked Bluetail in Europe: range expansion and population trends

摘要

Data are presented to illustrate the population increase and expansion in the breeding range of the Red-flanked Bluetail in Finland during the past 40 years. The changing status of this species in the rest of Europe over the same time period is discussed also.In 1973, HM drew BB readers' attention to the westward expansion of the Red-flanked Bluetail Tarsiger cyanurus (Mikkola 1973a,b). At that time, the regular breeding range extended west from the taiga zone of Siberia and the northern parts of European Russia to a small area of northeast Finland. Now, a little over 40 years later, it is clear that the species' range has continued to expand in a westerly direction, but also that the overall upward trend, in both numbers and range, masks a good deal of fluctuation. Indeed, the Red-flanked Bluetail remains vulnerable as a breeding species in Finland - its population size is still rather small and it is restricted to undisturbed, mature forests - and it remains on Finland's Red List of threatened species.