Causes of Variation in the Frequency of Polygyny in the European Pied Flycatcher Ficedula hypoleuca Population of Karelia

Abstract

Annual variation in the frequency of polygyny in the European pied flycatcher population is determined by a set of factors, with the primary factor being the sex ratio at the onset of the breeding season. The remaining factors, including individual characteristics of male and environmental conditions during this period, played a significant but secondary role. Facultative polygyny should be viewed as a mechanism to support the highest possible breeding productivity of individuals and populations, in unstable environmental conditions. It prevents an occurrence of nonbreeding females ready for mating and provides them with an opportunity to participate in breeding at a optimal time.