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Location Guam (to USA)
Central coordinates 144o 45.00' East  13o 15.00' North
IBA criteria A1, A2
Area 4,477 ha
Altitude 0 - 200m
Year of IBA assessment 2007





Site description The Guam National Wildlife Refuge IBA contains several portions of the larger Guam National Wildlife Refuge, including the USFWS-owned Ritidian Point and much of the US Air Force Overlay Refuge. The IBA includes known populations of the Mariana Crow and a snake-free enclosure with Guam Rails.

Key Biodiversity The IBA includes known populations of the Mariana Crow and a snake-free enclosure with Guam Rails. Micronesian Starlings were also observed in the IBA in 2005 (GDAWR, 2005). Additionally, the refuge is known to hold important habitat for the Guam subspecies of the Micronesian Kingfisher. Recovery plans for the kingfisher include reintroduction of the bird from captive breeding programs (USFWS, 2004b).

Non-bird biodiversity: Additional species known to occur in the proposed IBA include (Wesley, 2007): • Mariana Fruit Bat • Moth Skink • Green Sea Turtles • Serianthes nelsonii • Native tree snails • Coconut crabs • Land crabs • Native skinks, geckos • Native insects

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Guam Rail Hypotaenidia owstoni A1, A2  Extinct in the Wild 
Mariana Swiftlet Aerodramus bartschi unknown  unknown  A1, A2  Endangered 
Mariana Crow Corvus kubaryi resident  2005  10 individuals  good  A1, A2  Critically Endangered 
Micronesian Starling Aplonis opaca unknown  present  A2  Least Concern 

IBA Monitoring

2014 very high very unfavourable medium
Population
Good - based on reliable and complete / representative data

Human intrusions and disturbance war, civil unrest and military exercises likely in short term (within 4 years) some of area/population (10-49%) slow but significant deterioration medium
Invasive and other problematic species and genes invasive non-native/alien species/diseases - named species happening now whole area/population (>90%) moderate to rapid deterioration very high

Hypotaenidia owstoni Guam Rail 5 0 individuals 0 very unfavourable
Corvus kubaryi Mariana Crow 10 0 individuals 0 very unfavourable

Some of site covered (10-49%)  A comprehensive and appropriate management plan exists that aims to maintain or improve the populations of qualifying bird species  Substantive conservation measures are being implemented but these are not comprehensive and are limited by resources and capacity  medium 

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Guam National Wildlife Refuge Other 0 protected area contains site 4,477  

Land ownership The IBA is on land owned by the US Government, including the US Fish and Wildlife Service and the US Military.

Protection status The IBA contains several portions of the larger Guam National Wildlife Refuge, including the USFWS-owned Ritidian Point and much of the US Air Force Overlay Refuge.

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Recommended citation  BirdLife International (2014) Important Bird Areas factsheet: Guam National Wildlife Refuge. Downloaded from http://www.birdlife.org on 21/12/2014

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