Home > Islets > Oahu > Popoia ISLETS: OAHU > POPOIA Popoia (also known as Flat Island)   Popoia (also known as Flat Island) & Mokolua - Photo: F & K Starr Popoia (also known as Flat Island) - Photo: F & K Starr   Popoia (also known as Flat Island) - Photo: F & K Starr Popoia (also known as Flat Island) - Photo: C Swenson   Popoia (also known as Flat Island) - Photo: F & K Starr Physical Features Popoia, also known as Flat Island, is 4 acres in size and reaches a maximum elevation of 10 feet. True to its common name, the limestone islet is like a tabletop, although the surface is pitted with sink holes often used by nesting seabirds. It lies about 350 yards offshore from Kailua Beach Park in Kailua Bay on the windward coast of Oahu. The north, west, and south sides of Popoia are surrounded by a jagged reef. Visitors frequently land at the sandy cove on the southwest side. Regulations The islet is a State Seabird Sanctuary managed by the Hawaii DOFAW. Regulations in Hawaii Administrative Rules, Title 13 Chapter 125, protect wildlife and plants and restrict human activities in seabird sanctuaries. Federal law also protects seabirds, shorebirds, and threatened or endangered species. Visitors must obey all posted signs and stay away from the interior of the island, where dense concentrations of seabird burrows occur. Birds Wedge-tailed shearwaters and small numbers of Bulwer’s Petrel (Bulweria bulwerii) nest in burrows on over 70% of Popoia. A 2000 survey estimated over 3,000 breeding shearwaters on the islet. Due to the lack of deep soil and the porous nature of limestone, Popoia’s seabirds nest in small sink holes and crevices in the limestone. Polynesian rats, present on Popoia until at least 1941, were documented to prey on Bulwer’s petrels in the 1930s and 1940s. Because of it accessibility, many seabird researchers have visited Popoia since the first recorded survey in 1915, making it one the best surveyed colonies on Hawaii’s offshore islets. Plants Most of the plant cover on Popoia is composed of low-growing native species. Akulikuli (Sesuvium portulacastrum), a salt-tolerant succulent, is the dominant native species and covers much of the island with a luxuriant mat. The rare endemic, Capparis sandwichania (Maiapilo) is common on Popoia. A 2005 survey recorded 29 plant species, 15 of them native. However, the weeds are localized in a few patches on the southwest side and could be removed or controlled with consistent effort. It is no coincidence that the weeds are concentrated near the sandy cove where visitors usually arrive. People frequently and unknowingly carry weed seeds on their clothes, shoes, and gear, which then become established on offshore islets. Insects Recent insect collecting on Popoia has shown that most insects on the islet are alien, although the rare, Native yellow-faced bee is still present. Several species of ants, including big headed ants, are common. Marine Organisms Tide pools and rocky intertidal areas are common. Native shrimp are sometimes found in brackish pools. Human Uses A fishing shrine was once located on Popoia but was washed away by the 1946 tsunami. The translation of the islet’s name, ‘fish rot,’ likely refers to the offerings left at the shrine. Today, many people kayak or boat across to Popoia from Kailua Beach Park. Threats Burrowing seabirds are especially vulnerable to attack by dogs illegally brought on the islet and to trampling by visitors. Although currently localized, invasive weeds threaten the islet ecosystem by displacing native vegetation and eliminating seabird nesting habitat. Pickleweed (Batis maritimus) is a concern. Big-headed ants also threaten native insects. Polynesian rats were collected on Popoia in 1915 and were reported to be eating Bulwer’s Petrel (Bulweria bulwerii) as late as 1941. Although the 1946 tsunami may have extirpated them, the short distance to shore and frequent boat traffic make their eventual re-introduction likely. > Back to top of page Home  Islets  Species  Projects  Outreach  Links  About Us