Behavioral mechanisms preventing filial ovicide in house wrens

Abstract

Because unmated house wrens (Troglodytes aedon) regularly destroy clutches of conspecifics, we examined mechanisms that prevent breeding individuals from destroying eggs in their own nests. Results of our experimental field study indicate that the egg-destroying behavior of males is partially suppressed after mating and that the suppression may prevent filial ovicide in some individuals. At least 35% of males continue to destroy conspecific eggs during the incubation period of their mates. Because filial ovicide by males is prevented independently of female presence at the nest, we conclude, after eliminating alternative hypotheses, that filial ovicide by males is prevented through their recognition of nest locations. Egg-destroying behavior of females is also suppressed during the incubation. The suppression is stronger than in males because fewer females than males destroy foreign eggs over a comparable time period. Females respond to experimentally changed nest location and nest structure, but not egg coloration. We conclude that filial ovicide by females is prevented through the suppression of their eggdestroying behavior and through their recognition of nest location and structure.