The endemic avifauna of Guam and the Mariana Islands represent a unique assemblage of bird species found nowhere else in the world and thus, are of considerable biological and conservation importance. Unfortunately, most of these species are understudied and exist in precariously low populations. The endangered Mariana Common Moorhen (Gallinula chloropus guami), one of the last remaining native waterbirds, is a prime example of this since information is lacking for development of an effective recovery plan. Thus, this thesis attempts to provide much needed information regarding moorhen space use, seasonal movement, distribution, and abundance. In Chapter 2, the dynamic use of space and movement among moorhens within and across landscapes on multiple islands is explored throughout the annual cycle. Adult Mariana Common Moorhens were radio-marked on Guam (N=25) and Saipan (N=18) to determine home range and inter- and intra-seasonal movement patterns in 2000 and 2001. Birds were tracked throughout the dry and wet season. During the dry season, 48 and 11.1% of radio-marked adults on Guam and Saipan, respectively, dispersed from their capture site to another wetland site. During the wet season, 71.4 and 70% of radio-marked birds on Guam and Saipan, respectively, dispersed from their capture site to another wetland site. In 2001, Saipan moorhen surveys indicated juveniles dispersed during the onset of the rainy season. Thus, intra-island movement increased during the wet season. Similarly, inter-island movement occurred from Saipan to Tinian during the onset of the wet season. On Guam, moorhens were more likely to move greater average distances in the wet season than the dry season. Among Guam moorhens captured on Fena Reservoir (N=9), Guam and that dispersed during the 2000 wet season, 66.6% returned to Fena Reservoir during the 2001 dry season. During the wet season, the frequency of movement among sites was inversely proportional to the average distance between each site. Home-range estimates on Guam averaged 3.1 ha �� 4.8 SD and did not differ significantly between sexes or seasons. However, during the dry season, females exhibited significantly smaller mean core areas than males. To our knowledge, this is the first radio telemetry study that has taken a multi-island approach to understanding a mobile islands species throughout its annual cycle. In Chapter 3, population estimates for the Mariana Common Moorhen were determined on Guam, Saipan, Tinian, and Rota from island-wide surveys conducted from May through September 2001. We estimate the total adult moorhen population to be 287, including 90, 154, 41, and 2 adult moorhens on Guam, Saipan, Tinian, and Rota, respectively. Surveys also revealed changing moorhen distribution throughout the annual cycle and suggested inter-island movement from Saipan to Tinian occurred during the onset of the wet season. Surveys conducted on Fena Reservoir from March through August 2000 indicated adult moorhen numbers were significantly less than those from a similar survey in 1988. In addition, nest surveys of six territories revealed 58.8 % egg loss and 71.4% chick loss. Conservation efforts for this subspecies have mainly focused on protection of remaining wetlands. Efforts need to be expanded to include more active monitoring of populations, vegetation management, and predator control on wetlands throughout the Marianas and Guam. / Graduation date: 2003

Thesis (Ph. D.)--Northeastern University, 2008. / Title from title page (viewed Aug. 4, 2009) Graduate School of Arts and Sciences, Dept. of Biology. Includes bibliographical references.

The Common Moorhen (Gallinula chloropus) is a member of the rail family that usually inhabits slow moving or still bodies of water and can spread relatively rapidly and colonize a wide range of habitats. This species is a common resident bird, but a study of its basic ecology has not been published in Taiwan. The objective of this study was to examine the Common Moorhen¡¦s general breeding biology, as well as its diurnal activity patterns. I also made an attempt to describe its breeding behavior and time course. The possibility of morphometric characters difference between the male and female of the species was also examined. The study was conducted from December 2003 to May 2005 in Tainan county and Kaosiung Zhouzai wetland park. The majority of Common Moorhen breeding groups recorded during the study were monogamous. Both male and female birds share the tasks such as incubating the eggs, repairing nest and feeding chicks. The incubation period lasted about 21 days. Our study indicates that the clutch sizes of Common Moorhens ranged between 1 and 8 per female with two to five is typical. The primer P2 and P8 sexing method was successful in identifying the sexes of 52 Common Moorhen. The male was a little bigger than the female. There was significant difference in egg length, width and weight among individual females. Only a nest¡¦s inside diameter correlated to (linear regression) the number of eggs. I think that the number of Common Moorhen populations studied in this study can be quite high, which may be due to :(1) they seem to be breed all year long with good parental care and a successful breeding system (2) some individuals may have well concealed nesting areas, and (3) they have few predators in Taiwan, (4) high survival rate of chicks.