Kivonat:

opulation dynamics were studied in an urban Blackbird population in 5 breeding seasons between 1986 and 1992. From nest clusters - which seemed to represent the consecutive breeding attempts of a pair - the number of breeding pairs could be estimated as 72, 81, 72, 74 and 73 in the 5 breeding seasons. Similarly to the breeding population, yearly averages of breeding parameters - clutch size, hatching-, fledging- and breeding success - were also quite stable, consequently their density-dependence could not be detected. The stability of the urban breeding populations - which seem to be saturated - is maintained by the territorial behaviour, while in woodland populations the limited number of suitable nest sites and/or the lower winter survival may lead to the much lower breeding densities.