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Seasonal movement, home range, and abundance of the Mariana Common Moorhen (Gallinula chloropus guami) on Guam and the northern Mariana IslandsTakano, Leilani L. 18 March 2003 (has links)
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
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Muscle function during swimming and running in aquatic, semi-acquatic and cursorial birds a dissertation /Carr, Jennifer A. January 1900 (has links)
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.
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Ecological Study of the Common Moorhen (Gallinula chloropus)Chen, Chung-ying 21 July 2005 (has links)
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.
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