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LC
Chatham Gerygone Gerygone albofrontata

Justification
Although this species may have a small range, it is not believed to approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size has not been quantified, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

Taxonomic source(s)
Turbott, E. G. 1990. Checklist of the birds of New Zealand. Ornithological Society of New Zealand, Wellington.

Identification
12 cm. Small brown and white warbler. Olive brown head and upper parts, darker wings; adult male has white forehead and eyebrow stripe and underparts; female lacks white forehead, underparts are greyish white, and eyebrow, face and throat are yellowish; juvenile like female except upperparts olive grey, underparts yellower and eye brown instead of red. Similar species: None in range. Hints: . Voice: Short, loud song repeated often during breeding season.

Distribution and population
This species is confined to the forested parts of southern Chatham Island and five smaller offshore islands and islets in the Chatham Island group off the east coast of New Zealand. Subfossils indicate that the range once included several more islands in the group.

Population justification
The global population size has not been quantified, but the species is reported to be locally abundant (Heather and Robertson 1997).

Trend justification
Declines have been recorded on two islands, with a corresponding increase where introduced predators are controlled (del Hoyo et al. 2007), suggesting that this is a major threat. Overall, the species is suspected to be in decline.

Threats
Rats Rattus, feral cats and habitat reduction have caused a decline this century on Chatham Island (Heather and Robertson 1997).

References
del Hoyo, J.; Elliott, A.; Christie, D. 2007. Handbook of the Birds of the World, vol. 12: Picathartes to Tits and Chickadees. Lynx Edicions, Barcelona, Spain.

Heather, B. D.; Robertson, H. A. 1997. The field guide to the birds of New Zealand. Oxford University Press, Oxford, UK.

Further web sources of information
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
Ekstrom, J., Butchart, S., Harding, M., Fisher, S.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2014) Species factsheet: Gerygone albofrontata. Downloaded from http://www.birdlife.org on 18/12/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 18/12/2014.

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 Least Concern
Family Acanthizidae (Thornbills and gerygones)
Species name author Gray, 1844
Population size Unknown mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 790 km2
Country endemic? Yes
Links to further information
- Additional Information on this species