Reproductive Consequences of Autumnal Singing in Black Redstarts (Phoenicurus Ochruros)

Abstract

AbstractIn a migratory population of Black Redstarts (Phoenicurus ochruros) in central Europe, males were territorial and sang in autumn between the end of molt in early September and the abandonment of territories in October. Participants in autumn singing were adult males past their first potential breeding season; subadults rarely defended territories in autumn. Prior to the autumn singing period, unmated males and males after their first breeding season often dispersed to new locations within the study site. Pair associations with experienced female breeders still present on the breeding ground were preformed. Low winter mortality, site dominance, and fidelity to autumn territories allowed the reformation of 59% of autumnal pair bonds in the following spring. The mating pattern was assortative by age because the initiation of territory acquisition and pair formation was temporally segregated by more than six months between subadult and adult breeders. Males benefitted from mating with experienced females because they started breeding earlier and initiated more breeding attempts per season. Autumnal singing and territoriality, a phenomenon that has not attracted much attention, may play a key role in the understanding of age-related reproductive asymmetries in Black Redstarts. Age-related reproductive performance may be the underlying cause for the evolution of delayed plumage maturation in this species.