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Norfolk Island Gerygone Gerygone modesta

Justification
This species is classified as Near Threatened because although it has a very small range and population on a single island, its population is estimated to be stable or increasing and 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, and any evidence of declines would likely lead to its reclassification in a higher threat category.

Taxonomic source(s)
Christidis, L.; Boles, W. E. 2008. Systematics and taxonomy of Australian birds. CSIRO Publishing, Collingwood, Australia.

Identification
9-10 cm. Small, dull-coloured warbler. Dull grey-brown above and whitish below, greyer on face and flanks. Sexes similar. Slender, longish, black bill. White line from base of bill, above dark lores, over eyes. Broken white orbital ring. Tail has indistinct darker subterminal band with white spots except on central feathers. Juvenile more yellow, especially on throat. Similar spp. White-eyes Zosterops spp. are larger with prominent white eye-ring, more yellow or green overall and with differing voice. Voice Warble, rising and falling in pitch.

Distribution and population
Gerygone modesta is endemic to Norfolk Island (to Australia). It is widespread and abundant on the island, and is thought to number c.10,000 individuals (Garnett et al. 2011). The population is probably stable (R. Ward, M. Christian and R. Holdaway in litt. 2007, Garnett et al. 2011).

Population justification
The population within Norfolk Island National Park is estimated at at least 3,800 pairs (G. Dutson pers. obs.), with many more hundreds outside the park. The total population is therefore estimated at c.10,000 mature individuals (Garnett et al. 2011).

Trend justification
The population is suspected to be stable or slightly increasing (Garnett and Crowley 2000; R. Ward, M. Christian and R. Holdaway in litt. 2007, Garnett et al. 2011), and there are no immediate serious threats to the species.

Ecology
It is found only in remnant areas of tree or shrub growth on the island, such as rainforest, thicket, gardens and white oak pasture, and is common in weedy forest dominated by the exotic red guava Psidium cattleianum and African olive Olea africana but at a density about half that in native forest (G. Dutson pers. obs.). It is scattered and much less common in patchy forest and scrub away from the National Park (G. Dutson pers. obs.).


Threats
Although clearing for timber, cultivation, pasture and ongoing development (R. Ward, M. Christian and R. Holdaway in litt. 2007) has removed some habitat, there are no apparent serious threats that are likely to affect the viability of the population in the foreseeable future, but its restriction to such a small area could make it susceptible to catastrophe such as newly-introduced predators or disease. The population may be affected by the clearing of hedges and vacant land for the development of domestic and commercial buildings (R. Ward, M. Christian and R. Holdaway in litt. 2007). It coexists with the introduced black rat Rattus rattus and cats, and its behaviour and the positioning of its domed nests reduces the probability of predation (Garnett and Crowley 2000).


Conservation Actions Underway
Norfolk Island National Park was declared in 1986, and encompasses the main remaining stands of native forest on the island. Although the control of mammalian predators takes place within the Norfolk Island National Park, in 2006, it was noted that the control of rats was budget-constrained and limited in its effectiveness (S. Garnett in litt. 2006). There is an ongoing programme to control exotic shrubs within native forest in the National Park (Garnett et al. 2011). 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.Conservation Actions Proposed
Monitor the population through the analysis of birdwatchers' records. Install predator-proof fencing around the national park and other important habitat and remove introduced predators from within these areas (R. Ward, M. Christian and R. Holdaway in litt. 2007). The elimination of mammalian predators from the island or at least significant sections of it, with measures to prevent their reintroduction (Director of National Parks 2010), may benefit the species, despite them not being a serious threat.

References
Director of National Parks. 2010. Norfolk Island Region Threatened Species Recovery Plan. Department of the Environment, Water, Heritage and the Arts, Canberra.

Garnett, S. T.; Crowley, G. M. 2000. The action plan for Australian birds 2000. Environment Australia, Canberra.

Garnett, S.T., Szabo, J.K. and Dutson, G. 2011. The Action Plan for Australian Birds 2010. CSIRO Publishing, Collingwood.

Further web sources of information
Australian Govt - Action Plan for Australian Birds 2000 - Recovery Outline

Explore HBW Alive for further information on this species

View photos and videos and hear sounds of this species from the Internet Bird Collection

Text account compilers
Benstead, P., Garnett, S., McClellan, R., Symes, A. & Taylor, J.

Contributors
Christian, M., Holdaway, R. & Ward, R.

Recommended citation
BirdLife International (2014) Species factsheet: Gerygone modesta. Downloaded from http://www.birdlife.org on 27/08/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 27/08/2014.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Key facts
Current IUCN Red List category Near Threatened
Family Acanthizidae (Thornbills and gerygones)
Species name author Pelzeln, 1860
Population size 10000 mature individuals
Population trend Stable
Distribution size (breeding/resident) 36 km2
Country endemic? Yes
Links to further information
- Additional Information on this species