Ornis Hungarica. vol.8 Suppl. 1.. (1998) p.187-198.
Survival of Blackbird (Turdus merula) populations in relation to its migaratory status
In order to describe survival patterns of Blackbird (Turdus merula) populations living under different environmental conditions, data of the Hungarian Ringing Data Bank and data collectedatthe6csaBirdRingingStation(47°19'N, 19°15'E)were examined. Inthenational data, different subgroups were created, the frequency of ages between capture and recapture was calculated and compared according to: (1) male vs. female, (2) urban vs. -non-urban populations, (3) migrants vs. -residents, (4) data from different decades.. Similarly, in the case of the birds ringed at Ã“csa, life-tables were computed for all birds, and also separately for immatures and adults. The survival of birds ringed during 1974-82 was significnatly lower than those ringed between 1983-92. This difference was also found in the wild-resident population as well. The survival of urban and migrant populations was approximately the same. Survival of the wild-resident population in the first period was lower than that of the urban and migrant populations, but was approximately the same in the second period It seems that urbanisation is an advantageous strategy and makes overwintering possible in Hungary. On the other hand, for non-urbanised birds, migration offered a better chance for survival. This, - probably due to climatic and other environmental changes - seems to have changed in the last decade.