Paweł Czechowski
Ornis Polonica 2010, 51: 171–181
https://doi.org/10.12657/ornis.2010.3.0
Abstract: Most data (about 50%) came from south-western Poland. The majority of nests were built inside outbuildings (81.1%). Other were placed on building entrances (5.3%) and facades (1.7%), and under bridges (2.2%). Most nests were located at supporting beams (33.2%) and on walls (22.8%). They were frequently supported by various objects, e.g. lamps, electricity cables, small boards. The nests were built at the mean height of 2.6 m (SD=0.9; range 1.2–15 m). Two peaks of laying were distinguished: in late May (first brood) and early July (second broods). Mean laying dates advanced throughout the study period. Clutch size ranged 1–8 (mean 4.6 eggs, median 5 eggs) and decreased over breeding season. Breeding success was 85.3%. Nests containing eggs failed more often than nests with the young. Most common reasons for nesting failures were: nest desertion (23.6%), disappearance of eggs or nestlings (21.8%), nest destruction (17.3%), and death of nestlings (20.9%). Unhatched eggs were main reason responsible for partial nest losses.
