Dickinson, Janis IBN-9507365 Abstract Options in a variable social system Western bluebirds, in most cases, are monogamous, pair for life, and the male and female share equally in feeding offspring. However, several observations suggest that breeding opportunities are limited for males. Some males don't breed, but instead help feed nestlings at their parents' nests. Others fill vacancies at nests of widowed females and care for young that were presumably sired by the female's former mate; the presumed benefit of this apparent altruism is the opportunity to breed with the female the next time around. Superimposed on this variation in the reproductive options of males, breeding males vary in the extent to which they fertilize eggs of their social mates; DNA fingerprinting has revealed that over one-third of nests have at least one offspring that is not sired by the caregiving male. Dr. Dickinson will use single-locus fingerprinting techniques and field experiments to discover the processes underlying extrapair fertilization and to measure accurately the fitness consequences for breeders, helpers, and adoptive males. Through large-scale genotyping of the population using mini- and micro-satellite DNA fingerprinting techniques, she will characterize males successful in fertilization. Understanding the unusual array of alternative reproductive behaviors in this species will provide substantial insights into the evolution of monogamy, biparental care, and cooperative breeding. Dr. Dickinson will train three undergraduate or recently graduated biology majors in field ornithology. In the past, a high proportion of trainees have gone on to other jobs in field biology or, in most cases, graduate programs in animal behavior or ornithology. The results of these basic studies are likely to yield significant information concerning the population and conservation biology of avian species.
