BEHAVIORAL ASPECTS OF THE BREEDING BIOLOGY OF THE BLUE JAY CYANOCITTA CRISTATA (NEW YORK)

This project was designed to examine the behavioral aspects of the breeding biology of the Blue Jay, Cyanocitta cristata, especially as they relate to mating strategies and parental care patterns. The objectives were to (1) descriptively analyze the breeding behavior of the Blue Jay and (2) determine the nature and extent of sexual differences in parental activities during the breeding season.;The behavior of 33 pairs of Blue Jays, inhabiting a deciduous woodlands area in New York State, was observed for three breeding seasons and two winters. Data were collected on behavioral features of the breeding biology by observing individuals, interactions between mated pairs and interactions between parents and young.;The findings of this study show the Blue Jay to be a continuously monogamous species with a clear division of labor between the sexes. The overall patterns reveal the female to be the primary builder of the nest, the primary incubator, and the primary brooder of the young. The male is responsible for providing almost all the food for both the female and the young. Only the role of predator-protector shows clear shifts between the sexes over the breeding season. Altricial young continue to be fed, primarily by the male, for six - eight weeks post-fledging. Mated pairs tend to winter together, renesting the following spring. Mate changes occur only in the absence of a pair member.;Within each sex the distribution of chores changes significantly over the breeding season. Males increase their participation in behaviors associated with nest protection. Females, more active than males in all categories of behavior early in the season, shift their attentions to behaviors associated with nest care.;Male behavior rates show considerable yearly variation, with little, if any, associated patterns. Female behavior rates are more consistent from year to year. The division of labor is one which suggests that, in the long run, males maximize their fitness by adjusting their behavior to the demands of the female and the nest; females adjust their behavior to environmental factors.