Reproductive success of a long-lived seabird: Influences of behavioral coordination, basal metabolism, and investigator disturbance

The production of offspring is a fundamental objective in life, yet the factors affecting reproductive performance in long-lived birds are not fully understood. For example, long-term pairs and high quality individuals typically are superior breeders, but the bases of these relationships have not been identified. My dissertation uses a long-lived seabird (Leach's storm-petrel Oceanodroma leucorhoa) to explore how pair bond duration, individual quality, and life history affect avian reproductive performance.; First, I examine whether familiarity between long-term mates allows them to coordinate breeding activities, thereby enhancing reproductive success. I show that partners that coordinated their incubation shifts hatched their eggs earlier in the season than uncoordinated pairs, but that coordination was not influenced by pair bond duration. These results do not support the mate familiarity hypothesis. Instead, behavioral coordination (and therefore reproductive success) probably is influenced by the quality of the individual partners.; Next, I explore the proximate basis for variation in individual quality by testing whether basal metabolic rate (BMR) is related to reproductive performance. Males with low BMRs hatched their eggs earlier and their chicks had faster wing growth rates compared to males with high BMRs; BMR was consistent within males between years. Female BMR was not related to reproductive performance, nor was it consistent between years. These results suggest that BMR influences individual quality in males, and emphasize that different inherent attributes may underlie individual quality in each sex.; Lastly, I examine the effect of investigator disturbance during incubation on reproduction. I show that both weekly and daily disturbance reduced pairs' hatching success by ≥50%, and that most failures occurred because parents deserted their eggs. These results are consistent with life history theory—in long-lived species, parents should invest less when breeding conditions are unfavorable in order to increase the probability of survival to future breeding opportunities. Investigator disturbance also reduced nest-site fidelity, and thus may have had long-term negative effects on reproduction as well.; Together, these studies expand our understanding of factors influencing reproductive performance in long-lived birds, and provide insight into potential conservation strategies based on unique aspects of the behavioral ecology of long-lived species.