This study examines differing patterns of population colonization and extinction exhibited by the threatened black rail and the non-threatened Virginia rail inhabiting the same set of wetlands. These two cryptic marsh birds have similar natural histories, but may differ greatly in their ability to fly to new sites based on relationships derived from presence-absence surveys. This study will answer two main questions: Do the patterns of colonization implied from presence-absence data correspond to dispersal behavior? Are the correlates of population turnover the same when the proportion of sites occupied remains constant as when occupancy is increasing or declining? By surveying numerous small wetlands in the Sierra Foothills of California, this research will: compare dispersal distances estimated from turnover to direct measures from telemetry and genetic structure; track colonization of patches after recent extinction events caused by West Nile virus; determine the origin of colonists using genetic and isotope measures to untangle the contributions of short- and long-distance dispersal; and monitor for reoccurrence of West Nile virus by testing blood of all captured rails.
A broader impact resulting from this research will be the development of techniques for working with landowners to support conservation of rare species on their land. Private land supports a disproportionate percentage of endangered species and controversies concerning the protection of species under the Endangered Species Act occur. Few field studies are conducted on private property. This study provides a unique opportunity to explore ways of working with private landowners, and for educational outreach through a variety of approaches. The project will integrate research and education by training graduate and undergraduate students, and by offering local landowners, Audubon volunteers, high school students and teachers the chance to experience research in the field with researchers. Results from this project will advance Black Rail conservation by producing important data on dispersal ability and connectivity among regional populations, and informing management of wetlands created specifically for black rails in one of the most rapidly growing regions of California.
