Friday, July 02, 2004
Distribution and Abundance of the Mariana Common Moorhen
The Mariana subspecies of the common moorhen (Gallinula chloropus guami) is one of the last remaining wetland-dependent birds endemic in the Mariana Islands (located approximately 1,500 km east of the Philippine Islands) and is listed as endangered by the U.S. Fish and Wildlife Service. Mariana Common Moorhens are year-round breeders and are non-migratory residents of the Mariana archipelago, using freshwater wetland areas on Saipan, Tinian, Rota, and Guam (the only islands containing wetlands capable of supporting moorhens in the Mariana archipelago). Although historically Mariana Common Moorhens were considered numerous and widely distributed across taro patches, rice paddies and fresh and brackish wetland, significant wetland loss has occurred in the Marianas and today the population of the Mariana common moorhen is estimated to be less than 400 birds. In a recent study, Oregon State University graduate student Leilani Takano worked with USGS scientist Susan Haig to survey the islands at various temporal and spatial scales to determine a current population size. Island-wide surveys were conducted on Guam and the Commonwealth of the Northern Mariana Islands from May through September 2001. The counts estimate that the total adult moorhen population is 287, with 154, 41, 2, and 90 adult moorhens on Saipan, Tiknian, Rota, and Guam, respectively. They also examined seasonal distribution of wetland use by moorhens during dry and wet phases of the annual cycle. The authors suggest that monitoring of moorhens, management of invasive vegetation, and control of predators and ungulates on wetlands are all critical for recovery of this small population.
Takano, L.L., Haig, S.M., 2004, Distribution and abundance of the Mariana Common Moorhen: Waterbirds, v. 27, no. 2, p. 245-250. [Abs] [FullText] Copyrighted material courtesy of The Waterbird Society Catalog No: 1259
Contact:
Susan
Haig,
FRESC,
541-750-7482,
susan_haig@usgs.gov
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