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Location Palau, Koror
Central coordinates 134o 22.44' East  7o 15.60' North
IBA criteria A1, A2
Area 4,912 ha
Altitude 0 - 206m
Year of IBA assessment 2008

Palau Conservation Society

Site description The Rock Islands are a group of more than 500 high limestone islands scattered over a 621 km2 area of lagoon that stretches between Koror and Peleliu. The land area of the major islands in the group is approximately 35 km2. For the sole purpose of IBA delineation, the Rock Islands Complex includes the major island groupings of Ngeruktabel, Ulong, Mecherchar, Ngerukuid, and the larger islands around Nikko Bay — Ulebsechel, Ngermeuangel, and Ngeteklou. The IBA includes only terrestrial areas. The Rock Islands are Palau’s main tourism and recreation area and are managed by the Koror State Government (KSG 2005). Day to day operation of both the marine and terrestrial areas is managed by Koror State Conservation and Law Enforcement Division. The division employs 35 rangers and support staff who work around the clock.

Key Biodiversity The Rock Islands is one of only two IBAs where the Giant White-eye has been recorded. In the Rock Islands, the Giant White-eye was common only on the island of Ngeruktabel. The Palauan name Charmbedel ra Iouldaob suggests that the bird’s distribution may be limited in Palau - Iouldaob meaning the islands south of the main island of Babeldaob. Another occupant of the Rock Islands that does not trigger any IBA criteria is the Blue-faced Parrotfinch. This bird, rare in Palau, is found in the forests of the high limestone Rock Islands or often spotted in the Casuarina trees on sandy strands. The Blue-faced Parrotfinch is very rare on Babeldaob and is captured in only three out of the eight IBAs. Its small size and preference for the upper canopy makes it especially difficult to locate. Palau Ground-doves were seen at Ulong Island. Nicobar Pigeons were commonly seen at Ngerukuid Reserve. Micronesian Megapodes are present throughout the Rock Islands. Several seabirds, including the Audubon’s Shearwater, Bridled Tern, and Black-naped Tern are also present.

Non-bird biodiversity: Terrestrial habitats included in this IBA are exposed and protected strand vegetation, coastal scrub and limestone forests. These habitats support many of Palau’s endemic species of flora and fauna, including threatened species like the endemic rock island palm, and the Marianas fruit bat. The beaches on the islands provide Palau’s largest hawksbill turtle nesting sites and the surrounding waters are habitats for green sea turtles, dugongs, fish, invertebrates and coral reefs. The Rock Islands also includes the famous Jellyfish Lake, and many other marine lakes that support unique habitats and communities of organisms.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Micronesian Scrubfowl Megapodius laperouse resident  2005  present  A1, A2  Endangered 
Palau Ground-dove Alopecoenas canifrons resident  2005  present  A2  Near Threatened 
Palau Fruit-dove Ptilinopus pelewensis resident  2005  present  A2  Least Concern 
Micronesian Imperial-pigeon Ducula oceanica resident  2005  present  A2  Near Threatened 
Palau Swiftlet Aerodramus pelewensis resident  2005  present  A2  Least Concern 
Todiramphus cinnamominus resident  2005  present  A2  Not Recognised 
Micronesian Myzomela Myzomela rubratra resident  2005  present  A2  Least Concern 
Morningbird Pachycephala tenebrosa resident  2005  present  A2  Least Concern 
Palau Fantail Rhipidura lepida resident  2005  present  A2  Least Concern 
Mangrove Flycatcher Myiagra erythrops resident  2005  present  A2  Least Concern 
Palau Bush-warbler Cettia annae resident  2005  present  A2  Least Concern 
Caroline Islands White-eye Zosterops semperi resident  2005  present  A2  Least Concern 
Dusky White-eye Zosterops finschii resident  2005  present  A2  Least Concern 
Giant White-eye Megazosterops palauensis resident  2005  present  A2  Near Threatened 
Micronesian Starling Aplonis opaca resident  2005  present  A2  Least Concern 

IBA Monitoring

2008 medium not assessed low
Poor - based on little, or potentially unreliable/unrepresentative, data

Human intrusions and disturbance recreational activities happening now some of area/population (10-49%) no or imperceptible deterioration low
Invasive & other problematic species, genes & diseases invasive non-native/alien species/diseases - named species happening now some of area/population (10-49%) slow but significant deterioration medium

Some of site covered (10-49%)  No management plan exists but the management planning process has begun  Some limited conservation initiatives are in place  low 


IUCN habitat Habitat detail Extent (% of site)
Forest Beach and atoll forest; Lowland evergreen rain forest (tropical)  major

Land use

Land-use Extent (% of site)
nature conservation and research major
tourism/recreation major

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Rock Islands. Downloaded from on 28/10/2016

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