Sex-Role Partitioning and Parental Care by the Rook Corvus frugilegus

Abstract

Social behavior of the rook, C. frugilegus, was studied in a rookery near Trondheim, central Norway and related to parental investment. The female expends relatively little energy in reproduction. Because she is dependent on her mate for food during most of the breeding season she may suffer by mating with a qualitatively poor male. The rate at which the male feeds the female during the incubation period may affect the ability of the female to invest in her brood during its later stages, and thus the brood survival. Guarding the nest and the nestlings also represents an important part of the parental care by the female. The reproductive costs of the male are more closely comparable with his energy expenditure in contrast to the female, because he invests a large part of his energy expenditure in the young.