Zosterops tenuirostris


Taxonomy [top]

Kingdom Phylum Class Order Family

Scientific Name: Zosterops tenuirostris
Species Authority: Gould, 1837
Common Name(s):
English Slender-billed White-eye

Assessment Information [top]

Red List Category & Criteria: Near Threatened ver 3.1
Year Published: 2013
Date Assessed: 2013-11-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S.
Contributor(s): Christian, M., Garnett, S., Holdaway, R. & Ward, R.
Facilitator/Compiler(s): Ekstrom, J., Garnett, S., McClellan, R., Symes, A. & Taylor, J.
This species is listed as Near Threatened because although it has a very small range and population on a single island (and has declined historically), its population is estimated to have been stable for several decades. It has not been significantly affected by introduced predators, including rats, and therefore there is not thought to be any plausible threat likely to lead to very rapid future declines. If such a plausible future threat were to be identified it would warrant classification as Vulnerable.

2012 Near Threatened

Geographic Range [top]

Range Description: Zosterops tenuirostris is found on Norfolk Island (to Australia), where it is thought to number c.4,500 mature individuals, mostly restricted to the Norfolk Island National Park. It underwent declines since the 1960s, particularly outside the park, which continued in the period 1987-1997, however numbers since appear to have stabilised.

Norfolk Island
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: A survey in 2010 estimated a population of c.4,000 birds in the National Park on the basis of 74 records in point counts at a density of c.900/km2; the total population has therefore been estimated at 4,500 mature individuals (Garnett et al. 2011).
Population Trend: Stable

Habitat and Ecology [top]

Habitat and Ecology: It lives in rainforest and tall secondary growth. It uses its long, down-curved bill to probe fissures in bark for insects, although it also takes fruit, including those of exotic species. It is also observed feeding on nectar from flowers of the endemic Pittosporum bracteolatum (M. Christian in litt. 2007). It forages in parties and appears to have a different ecological niche to that of the self-introduced Silvereye Z. lateralis.

Systems: Terrestrial

Threats [top]

Major Threat(s): The species has gradually disappeared from all parts of the island that have been extensively cleared for timber, cultivation, pasture and continued development (M. Christian in litt. 2007). This species is also presently threatened by the replacement of cleared native forest with invasive weeds (M. Christian in litt. 2007). Its decline was probably exacerbated by the arrival of black rat Rattus rattus. Cats are opportunistic predators of adult birds (R. Ward in litt. 2007).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
The Norfolk Island National Park was declared in 1986, encompassing most of the main remaining stands of native trees on the island. Rat baiting and cat trapping is carried out within its boundaries. In 2006, it was noted that control measures for rats were budget-constrained and limited in their effectiveness (S. Garnett in litt. 2006). Responsible cat ownership is being encouraged, through sponsorship of a cat neutering clinic. The Norfolk Island Region Threatened Species Recovery Plan (Director of National Parks 2010) recommends a set of recovery measures required to reduce or remove threats to native species on the island. Rabbits have been removed from Phillip Island.

Conservation Actions Proposed
Monitor trends in the population through analysis of birdwatchers' records. Consider introducing the species to Phillip Island. Install a predator-proof fence around the national park, Hundred Acre Reserve and other important areas of habitat, and remove introduced predators from within these areas (M. Christian in litt. 2007). Eliminate mammalian predators from the entire island, or at least significant sections, and prevent reintroduction (Director of National Parks 2010). Carry out research into the impacts of introduced predators (M. Christian in litt. 2007).

Citation: BirdLife International 2013. Zosterops tenuirostris. The IUCN Red List of Threatened Species. Version 2015.2. <>. Downloaded on 01 September 2015.
Disclaimer: To make use of this information, please check the <Terms of Use>.
Feedback: If you see any errors or have any questions or suggestions on what is shown on this page, please provide us with feedback so that we can correct or extend the information provided