[Characteristics of the distribution of birds infected with hemosporidians (Sporozoa, Haemosporidia) during the fall migration in flight waves].

Chaffinches, infected with hemoproteids (Haemoproteidae) and leucocytozoids (Leucocytozoidae), are uniformly distributed in the ranges of each nonequivalent from the point of view of bioenergetics migratory wave. Extensiveness of infection of birds with leucocytozoids in autumn increases reliably at the time of late migratory waves as compared to early ones. The last flight wave, which is observed in the Kurskaya Kosa in the second half of October, consists, in general, of chaffinches which have already gone through the leucocytozoonosis. Concentration of infected birds at the end of the species migration flow can be regarded as a peculiar parasitic filter delaying the birds, which have been seriously ill, from flying away to wintering places at the most favourable periods. The thesis on different influence of hemosporidians on energetic balance of birds during spring and autumn migrations is substantiated. Hypothesis has been advanced on the causal relationship between high bird mortality during spring migration and the most high extensiveness and intensity of their infection with hemosporidians.