The ‘Ata IBA comprises the whole of the 2.3 sq.km. volcanic island of ‘Ata, the southernmost island of the Tongan archipelago. The island is mostly forested and is currently uninhabited and very rarely visited by people. ’Ata has some of the largest seabird colonies in Tonga especially wedge-tailed shearwaters, masked, red-footed and brown booby, and black and brown boobies. Together these are believed to number over 50,000 birds.
‘Ata is renowned for its seabird colonies but these remain very poorly documented. Apart from the collectors of the Whitney South Sea Expedition who visited the island 13-14 July 1925, only Rinke (1991) has published ornithological observations. The apparent loss of the Pacific harrier and the exotic European starling between the visits of the WSSE and Dieter Rinke’s visit is of great interest. The island indubitably supports over 10,000 pairs of seabirds (A4iii), probably comprising 15 species. Whilst the breeding populations of the three species of booby and the two species of noddy both fulfill IBA criteria (A4ii). In addition, the Polynesian starling is a ‘central polynesian’ restricted range species (A2).
Non-bird biodiversity: Rinke (1991) records the abundance of Ficus spp.in the forest on the plateau, as well as the presence of Inocarpus edulis and coconuts and pawpaw. Other species noted include Wedelia biflora thickets, Pisonia grandis, Hibiscus tiliaceus and Casuarina equisetifolia. He confirmed the presence of the Polynesian rat Rattus exulans and three skinks. Emoia cyanura, E.pheonura and Cryptoblepharus eximius.
Pressure/threats to key biodiversity
The remotest of Tonga’s islands and rarely if ever visited by people. Habitat destruction, poaching for food and feathers, and introduced species are the principal threats to remaining Tongan biodiversity (WWF 2001). Introduced pigs, rats and cats can have catastrophic impacts on breeding seabirds and passerines. There are no national parks in Tonga and Rinke (1986) has suggested that the greatest potential for conservation lies in the protection of uninhabited, forested, and predator-free islands such as ‘Ata, Tofua and Late that are stocked with threatened flora and fauna from inhabited islands. Paleoecology studies suggest many of the target species once occurred on these refuge islands and this approach may offer the best chance for conservation of many threatened species.
Conservation responses/actions for key biodiversity
There are no research or conservation projects on ‘Ata at the present time (Prescott &
Habitat and land use
Site description The ‘Ata IBA comprises the whole of the island of ‘Ata, a volcanic island that rises to 355 m. The island is very isolated being over 140 km SSW of Tongatapu. Rinke (1991) visited the island (5-9 April 1990) and provides the following description. The island is comprised of a ‘plateau’ bordered by two mountains in the west and two lower peaks in the east, almost completely surrounded by steep cliffs between 60-100 m high but there is a single landing place on a short sand beach on the NW coast. The plateau is heavily forested but vegetation on the cliffs is sparse. The island is uninhabited and is very rarely visited by people today, however, it was once inhabited but the population was removed to live in ‘Eua in the 1860s. Evidence of their former presence is found in lingering populations of fruit trees and crops.
BirdLife International (2020) Important Bird Areas factsheet: 'Ata Island. Downloaded from
http://www.birdlife.org on 02/04/2020.