Cyclical phenomena in the dynamics of the population of feathered predators in agricultural landscape in the Perm region

It has been carried out the regressional analysis of the density of feathered predators populations and factors which likely can define fluctuations of their numbers (trophic and meteorological) m order to explain the cause of the cyclicity. On the one hand the density of feathered predators is caused by fluctuations of the victims directly or indirectly because of meteorological indices. On the other hand, there is a connection between the indices of the dynamics of feathered predators and the factors affecting them, but similar cycles are aksent.