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Site description (2007 baseline):

Niuafo’ou IBA comprises the whole island of Niuafo’ou which until recently supported the only extant population of the Tongan megapode Megapodius pritchardii. The island is an active volcano and the megapodes lay their eggs in soil heated by volcanic ducts. An island-endemic form of the Polynesian Starling Aplonis tabuensis nesiotes occurs on the island, along with two other range restricted species, the Crimson-crowned Fruit-dove Ptilinopus porphyraceus and the Blue-crowned Lorikeet Vini australis.

Seventeen bird species have been recorded breeding on Niuafo’ou (Goth & Vogel 2001; Rinke 1986,1991). Niuafo'ou is best known for the Tongan megapode Megapodius pritchardii, the only surviving megapode east of Vanuatu. Megapodes were probably common throughout Fiji, Tonga and Samoa but were one of the first species to succumb to the arrival of the first people. The Tongan megapode is thus of considerable national and international significance. Megapodes have the unique behaviour of laying their eggs in unconsolidated soils or organic debris, allowing external heat sources to provide for incubation without any parental care. On Niuafo'ou the Tongan megapode seek out well established `breeding grounds' where the soil is heated by volcanic ducts. Sixteen of these sites are known but those outside the crater are no longer used because of continued removal of the eggs by the islanders. Other unknown and inaccessible sites may also occur. The current population of the Tongan megapode on Niuafo’ou is estimated to be 188-235 pairs Goth & Vogel 1995), but it is a shy and rarely seen species (Rinke 1991). There is only one native passerine on Niuafo’ou, an endemic form of the Polynesian starling Aplonis tabuensis nesiotes. This and the Blue-crowned Lory Vini australis are two central Polynesian restricted range species which occur on the island, the former is abundant and the latter common . Two feral species introduced to Fiji have also arrived naturally or been boat-assisted to Niuafo'ou, the red-vented bulbul Pycnonotus cafer and the jungle mynah Acridotheres fuscus. Two seabirds, tropical shearwater Puffinus bailloni (previously Audubon’s shearwater P.lherminieri) and the white-tailed tropic bird Phaethon lepturus breed on Niuafo'ou, whereas the wedge-tailed shearwater P. pacificus is collected in large numbers on the island, but there is no evidence of breeding (Goth & Vogel 1995).

Non-bird biodiversity: Niuafo’ou’s biodiversity has not been well studied. There is no plant list for the island but there are no known endemic species (Whistler pers.comm. Oct.1994). Within Tonga, Niuafo'ou is well known for the fine Ta'ovala weaved from the inner bark of the Fanakio tree, Sterculia fanahio which is widely regarded to occur only on Niuafo'ou. This is true in respect of Tonga, but it is also found in Samoa, Rotuma and Niue. It is widespread on the island and will remain so as long as fruiting trees survive and the Pacific pigeon Ducula pacifica survives in numbers to distribute its seeds. Seven skinks and two geckos have been recorded on Niuafo'ou . None of these are island or Tongan endemic species but two of them Emoia nigra and E.adspersa are not found south of the Niuas (Prescott & Folaumoetu’I 2004).

Niuafo'ou is the Kingdom of Tonga's most remote island and at 640 km north of Tongatapu it is closer to Fiji and Samoa. The 8-km-wide circular island forms the summit of a largely submerged basaltic shield volcano. The island encloses a 5-km-wide caldera that is mostly filled by a lake whose bottom extends to below sea level. The inner walls of the caldera drop sharply to the caldera lake, Vai Lahi, which contains several small islands and pyroclastic cones on its north east shore. Niuafo'ou is an active volcano and there have been 11 eruptions since 1814, the last major eruption being in 1946 after which the inhabitants were evacuated to 'Eua. Some of the former residents returned in 1958 and today the population has risen to approximately 800 living in about 140 households in eight villages. Much of Niuafo'ou is barren lava flow. Approximately one third of the land area has potential for agriculture, and two soil types are currently recognised, a clay with good agricultural potential which covers slightly more than half of the arable land and a sandy loam, with lesser potential, which covers the remainder. Most of the accessible arable areas have or are planted on an extensive basis to yams, cassava, taro, bananas, plantains and vegetables. The only commercial crop that has been planted is copra. Undisturbed dense, humid broad-leaved forest is only found on the inner walls of the crater lake and its islands, while the island's outer slopes comprise a mosaic of regenerating forest, agricultural gardens and lava flows of varying antiquity. The majority of agricultural areas are on the north and eastern slopes, while the southern and western slopes are relatively barren.

It is probable that all nesting sites on Niuafo'ou are known to villagers and are harvested, and at least 50% of all eggs laid are collected or destroyed (Goth & Vogel 1995). Adults are also hunted on a small scale, and adults and chicks are predated by feral cats and dogs, while pigs may compete for food. Fonualei is uninhabited so the threats of hunting and human disturbance are less immediate for the population there, however, Founalei is small and an active volcano, a major eruption could see the demise of the entire population.

A well illustrated, bilingual interpretive booklet on the Tongan megapode has been published (Rinke et al. 1993). The Tongan megapode is protected by law - Birds and Fish Preservation Act, but this is not enforced on Niuafo'ou. From 1991 to 1993 60 eggs were conveyed to the island of Late, and 35 eggs and chicks were transferred to Fonualei, both uninhabited islands and rarely visited by humans. Surveys of Late in 2003 and 2004 failed to find any Tongan megapode, but confirmed that the translocation to Fonualei had been successful (Watling 2003,2004). It was planned for these translocation initiatives to extended to Tofua, however currently there are no research or conservation projects in place or planned.

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Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Niuafo'ou (Tonga). Downloaded from https://datazone.birdlife.org/site/factsheet/niuafoou-iba-tonga on 23/12/2024.