Data Zone
Justification of Red List category
This species was endemic to Norfolk Island, Australia, however it rapidly declined primarily due to predation by black rats. Four records during an island-wide survey in 1979 were the last multi-observer records, with poorly documented reports suggesting the species possibly persisted until the first decade of the 21st century. Following methods developed in a series of papers published in 2017 (Akcakaya et al. 2017, Keith et al. 2017, Thompson et al. 2017), the probability that the species is extinct based on records and surveys is 0.99, and the probability it is extinct based on threats is 0.98. Accordingly, it is classified as Extinct.
Population justification
While common and widespread in 1908 (Hull 1910) and 1926 (Mees 1969), it was very scarce in 1962, with a population estimated at <50 birds, and only two birds were seen in 1968 (Mees 1969). Four records during an island-wide survey in 1979 were the last multi-observer records (Schodde et al. 1983). Formal searches in the 1980s and in 2009 (Dutson 2013) failed to find the species, but poorly documented reports (detailed in Dutson 2013) suggested persistence. There have been no records since 2009 and from 2017 to 2019 postgraduate students spending three months a year working in prime white-eye habitat on the island and have seen none (R. Clarke unpublished, in Clarke et al. 2021). Intensive nest searches over three breeding seasons in 2018–2020 during peak breeding months and an island-wide point-count survey between October and November 2019 also failed to detect the species (Nance et al. 2023a).
Following methods developed in a series of papers published in 2017 (Akcakaya et al. 2017, Keith et al. 2017, Thompson et al. 2017), the probability that this species is extinct based on records and surveys is 0.99, and the probability it is extinct based on threats is 0.98 (Clarke et al. 2021). It is accordingly considered Extinct.
Trend justification
This species is considered extinct. Four records during an island-wide survey in 1979 were the last multi-observer records (Schodde et al. 1983), with poorly documented reports suggesting the species possibly persisted until the first decade of the 21st century (Clarke et al. 2021).
Zosterops albogularis was endemic to Norfolk Island (to Australia). By the 1970s it had become confined to weed-free indigenous forest in and around the Norfolk Island National Park.
While the most recent records were all in rainforest and only a few in weedy forest (Higgins et al. 2006), they were historically recorded nesting in orchards (Hull 1910) and red guava Pisidium cattleianum trees and feeding on fruits of olives Olea europaea (Mees 1969) and insects (Christian 2005).
Threats for this species have operated at an acuity and spatial scale that have driven it extinct. Following methods developed in a series of papers published in 2017 (Akcakaya et al. 2017, Keith et al. 2017, Thompson et al. 2017), the probability it is extant based on threats is 0.02 (Clarke et al. 2021). The principal threat was predation by black rats Rattus rattus which are thought to have been introduced in the mid-1940s (Robinson 1988). Most other Zosterops species persist alongside rats, including two other species on Norfolk Island, but rats appear to have exterminated the Robust White-eye Z. strenuus within ten years of colonising Lord Howe Island (Hindwood 1940, Sharland 1929). The effects of predation have been exacerbated by the clearance of much native forest and invasion of the remainder by exotic weeds. Although being baited on the ground in the National Park since the early 1990s, rats have remained common in trees and shrubs and their arboreal behaviour renders such control programs less effective (Nance et al. 2023b). Loss of good habitat to agriculture, predation by cats Felis catus and competition from the self-introduced Silvereye Zosterops lateralis, first recorded on the island in 1904, may have contributed to the white-eye’s decline but are unlikely to be primary causes (Clarke et al. 2021).
13-14 cm. Medium-sized, warbler-like bird. Sexes similar. Bright green head, olive-green back, clear white underparts and white eye-ring. Similar spp. Distinguished from other White-eyes Zosterops spp. by large size and white underparts.
Text account compilers
Vine, J.
Contributors
Dutson, G., Garnett, S. & Clarke, R.
Recommended citation
BirdLife International (2024) Species factsheet: White-chested White-eye Zosterops albogularis. Downloaded from
https://datazone.birdlife.org/species/factsheet/white-chested-white-eye-zosterops-albogularis on 22/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 22/11/2024.