Population demography, resource use, and movement in cooperatively breeding Micronesian kingfishers

Island systems and species are susceptible to extinction because of their small population size and an ecological naivete from an evolutionary past lacking strong competition and predation. For example, only one-fifth of the world's bird species occur on islands, yet more than 90% of the avian extinctions witnessed during historic times were island forms. Introduced predators and competitor species are among the major conservation issues facing insular systems. On the island of Guam, brown tree snakes (Boiga irregularis ) are responsible for the local extinction of twelve native forest birds. The endangered Guam Micronesian Kingfisher (Todiramphus cinnamominus cinnamominus) is one of the species affected by the introduced snake, as the bird remains only in captive breeding institutions on the U.S. mainland. In addition to Guam, the islands of Pohnpei and Palau host endemic subspecies of Micronesian Kingfisher (T. c. reichenbachii and T. c. pelewensis respectively) that are similarly threatened with extinction.;Previous investigations into the behavioral ecology of the Pohnpei subspecies of Micronesian Kingfisher yielded observations of cooperative social behaviors. Over the past three decades, much research has focused on cooperatively breeding species, which are commonly characterized by non-breeding individuals that delay dispersal and assist others with reproduction. Research addressing cooperative breeding suggests that the behavior is a complex response to interacting factors including life history characteristics, demography, resources, movement, and behavior.;The dearth of information available about critically endangered Micronesian Kingfishers, combined with their potential to provide new insights into cooperative social behaviors, inspired the research presented in this dissertation. The aims were two-fold; results were intended to bolster our understanding of cooperative social behaviors while simultaneously providing vital information to conservation practitioners. Methodology for determining the sex of study individuals is presented in chapter two, which facilitated investigations that followed.;Chapter three addressed the interaction between kingfishers and resources at both the landscape and home range scale. Higher population densities are associated with lowland mangrove, marsh forested habitats, and open vegetation types at the landscape scale. (Abstract shortened by UMI.).