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Location Northern Mariana Islands (to USA), Tinian Island
Central coordinates 145o 38.00' East  15o 0.00' North
IBA criteria A1, A2
Area 9,888 ha
Altitude 0 - 178m
Year of IBA assessment 2007

Site description The proposed Tinian Island IBA encompasses the majority of the island, excluding a small settlement in the southern part of the island and including a large military leasehold area in the north. Part of the military leasehold area is designated a National Historical Site. The military leasehold areas are used for training exercises, but are uninhabited. The proposed IBA includes the Hagoi Marsh and Marpo Swamp areas, which are important as water sources and as animal habitat.

Key Biodiversity Engbring et al. (1986) reported that the Tinian Monarch, endemic only to Tinian, was present in every surveyed habitat in Tinian. The USFWS (2005) also found that the Tinian Monarch inhabited a variety of forest habitats, including native, secondary, and introduced vegetation. Engbring et al. (1986) also found that other native birds were distributed throughout the island. Engbring et al. (1986) found that the northern part of Tinian, the location of Hagoi marsh, held the largest population of monarchs and was important for wetland birds, including the US federally listed and protected Mariana Common Moorhen. Tanaka and Haig (2004) found that Mariana Common Moorhens appear to use Tinian’s Lake Hagoi, particularly during the dry season. Wiles et al. (1985) and O’Daniel and Krueger (1999) found the Micronesian Megapode on Tinian. O’Daniel and Krueger (1999) reported sightings of the Megapode were made at Maga, Upper Mt. Lasu, and Bateha, all sites with native limestone forest. These sites are located on the center escarpment of the island. Native forest is also found on the eastern part of the island in Unai Dankulo (NPS, 2001). Reichel (1991) reported over 270 pairs of breeding seabirds on Tinian, including 150 pairs of White Terns.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Micronesian Scrubfowl Megapodius laperouse resident  present  A1, A2  Endangered 
Mariana Fruit-dove Ptilinopus roseicapilla resident  1982  2,500-9,999 individuals  unknown  A1, A2  Endangered 
White-throated Ground-dove Alopecoenas xanthonurus resident  1982  250-999 individuals  unknown  A1, A2  Near Threatened 
Micronesian Myzomela Myzomela rubratra resident  1982  2,500-9,999 individuals  unknown  A2  Least Concern 
Rufous Fantail Rhipidura rufifrons resident  1982  20,000-49,999 individuals  unknown  A2  Least Concern 
Tinian Monarch Monarcha takatsukasae resident  1982  20,000-49,999 individuals  unknown  A1, A2  Vulnerable 
Bridled White-eye Zosterops conspicillatus resident  1982  100,000-499,999 individuals  unknown  A1, A2  Endangered 
Micronesian Starling Aplonis opaca resident  1982  10,000-19,999 individuals  unknown  A2  Least Concern 

IBA Monitoring

2007 high not assessed not assessed

Invasive & other problematic species, genes & diseases invasive non-native/alien species/diseases - named species happening now majority/most of area/population (50-90%) slow but significant deterioration high

Protection status There are no formal protective mechanisms, although the military must ensure the integrity of the National Historical Site and natural features of the area. There are some local, small conservation areas on Tinian, such as the Airport Mitigation Site, a small conservation area in the southwest corner of the island established for Tinian Monarchs, and a small mitigation area in the central part of the island (A. Marshall, pers. comm.).

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Tinian Island. Downloaded from on 25/10/2016

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