ИСТИНА

Strange visitors to the pied flycatcher nest-boxes during period of rearing of nestlings are typical for this species, but the place of this phenomenon in the life of population is still obscure. Quantitative analysis of visitors composition and their relationships with host birds in Moscow region population was made on a base of data obtained during 15 breeding seasons. Visual observations at 268 pairs, 17 single females and 3 single males feeding nestlings were provided during 1050 hours. Total amount of visits of strange pied flycatchers to nest-boxes of these parents was equal to 760. Most visits were made by males (94%). Conspicuously coloured males visited strange nest-boxes relatively more often in comparison to dark ones. Females and young birds were rather rare visitors (5 and 1% respectively). The reaction of host birds, including single parents, on the presence of strangers more often was aggressive. Among marked visitors were registered both bachelor birds and paired males of various ages before and after hatching their own offsprings. Most adult birds and all young ones behaved themselves as “inspectors”, one male demonstrated sexual display at the presence of host female and another part of visitors were trying to feed nestlings. Among them only 9 males and one female were observed as “helpers”. The role of visitors in the population hardly ever could be regarded as important factor in rearing of conspecific youngs. At the same time, information obtaining by visitors during inspecting of strange nest-boxes could be useful for their future life.