Nest biology of urban populations of cavity-nesting birds

Abstract

Nesting features of four species of cavity-nesting birds—common starling (Sturnus vulgaris L.), great tit (Parus major L.), common redstart (Phoenicurus phoenicurus L.), and pied flycatcher (Ficedula hypoleuca Pall.)—have been studied in city. Under urban conditions, number of eggs in a nest of a redstart is significantly larger, while for great tit and pied flycatcher it is significantly smaller; differences between the populations of starling are insignificant. Success of reproduction for the cavity-nesters is significantly higher in a city and exceeds the reference value for all the species by 10–20%. The number of chicks per a reproduction attempt is also higher in city for all the species. Starling population in city exceeds the reference population in the success of reproduction mainly due to a decrease in the percentage of abandoned eggs. The main reasons for an increase in the reproduction success of other species at the urbanized locality are weakened pressure of predators and a decrease in the percentage of abandoned broods.