Rock Islands

Year of compilation: 2008

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.

Pressure/threats to key biodiversity
This IBA includes the oldest conservation area in Palau, the Ngerukuid Islands, which was established by national legislation in 1956. The Rock Islands is arguably the most effectively managed protected area in Palau. An overwhelming majority of visitors to Palau visit these islands and surrounding reefs and the state government enjoys substantial economic benefit from protecting and managing this valuable resource. The number of visitors to the Rock Islands is steadily increasing and this trend is expected to continue. The main threats to the biodiversity of the Rock Islands and the surrounding waters are the potential impacts of the rising number of visitors and the presence and introduction of invasive species, including rodents, cats and macaques. In 2007, the fee to visit the Rock Islands was increased, however, whether this fee increase will affect the visitor numbers is yet to be determined.

Recommended citation
BirdLife International (2023) Important Bird Areas factsheet: Rock Islands. Downloaded from on 06/02/2023.