The Relationship Between Individual Differences in Male Song Frequency and Parental Care in Blackcaps

Abstract

Abstract Song rates in male blackcaps were examined over the course of the breeding season and compared with various aspects of mating and later parental behavior in individual birds. Song rates decreased steadily over the breeding season although relative individual rates remained constant. Early territory holders sang more and mated faster than late-comers. Song frequency was positively related to alarm call frequency during nesting but negatively related to male incubation and offspring feeding rates. Surprisingly, under the conditions studied, higher song rates were indicative of higher nesting success. This demonstrates the potential role of song frequency in the advertisement of territorial quality. There may well be either environmentally dependent differences in parental care as adaptations to temperature, food or predation pressure or simply a trade-off for males between singing and parental care, where early arriving males derive greater fitness benefits from singing, while late arriving males benefit more from engaging in parental care.