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Crow Honeyeater Gymnomyza aubryana
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Justification
This species is listed as Critically Endangered because it is believed to have an extremely small population mainly confined to the south of New Caledonia, and is probably undergoing a very rapid population reduction owing to predation by introduced mammals. It is undoubtedly highly threatened and in need of urgent conservation action to investigate and halt this decline.

Taxonomic source(s)
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.

Identification
41cm. Very large, crow-like honeyeater with orange facial wattles. Plumage all glossy black, bill grey above and yellow below, legs yellow and facial skin varies from yellow to red. Long rounded wings and fairly long neck and tail. Similar spp. New Caledonian Crow Corvus moneduloides and Melanesian Cuckoo-shrike Coracina caledonica have short dark bills and no bare facial skin - crow has short tail and cuckoo-shrike has long pointed wings. Voice Loud, repeated series of slightly varied phrases, typically a loud nasal note e.g. chong, followed by a descending series, e.g. tchku-tchku-... Harsh scolding tcharr or wa-wa similar to parrot or crow. Hints Listen at dawn.

Distribution and population
Gymnomyza aubryana is endemic to New Caledonia (to France) where it is now mainly restricted to small populations scattered throughout the south of the island. Extensive surveys in 2003-2006 only found it in the Parc de la Rivière Bleue area, the slopes of the Kouakoué (J Theuerkauf in litt. 2007), Pourina and Ouiné valleys, Rivière Blanche and Mont Pouédihi slopes. The total area where the bird has been recorded now covers less than 400 km2 (Létocart 2006). The only relatively recent records from the north are from Mt Panié (Ekstrom et al. 2000, 2002), with one individual seen during a survey in 2011 (R. Stirnemann in litt. 2012) and Pouembout (N. Barré in litt. 2003). It appears to be localised and uncommon even in favoured areas, although c.18 pairs known in the study area of Rivière Bleue, each occupying c.1 km2 of forest, is extrapolated to 160 pairs across this protected area (Y. Létocart in litt. 1999). This estimate has been considered over-optimistic (N. Barré in litt. 1999), particularly if pairs require c.1 km2, and may not be representative of the density elsewhere (Chartendrault and Barré 2005, 2006). The total population was estimated at 1,000-3,000 birds in 2000, based on territorial areas of c.0.25 km2 and a patchy distribution across c.1,200 km2 of suitable forest (Ekstrom et al. 2000), however in 2007 it was thought to have dropped to a few hundred (Chartendrault and Barré 2005, 2006). Even allowing for an overestimate in 2000, the species is thought to have undergone a serious decline in recent years. It was last seen at the often-visited Mt Koghis in 1974, and it appears to have declined in Rivière Bleue since 1980 (Vuilleumier and Gochfeld 1976, Y. Létocart in litt. 1999, Ekstrom et al. 2000). While precautionarily a revised population estimate in the low hundreds is now adopted, the species's real population size and trends remain somewhat unclear. There remain large areas of potentially suitable habitat that have not been searched, it occurs outside the forest matrix and reasons behind apparent population declines are not well understood.

Population justification
The population is estimated to number 50-249 mature individuals based on an assessment of known records, descriptions of abundance and range size. This is consistent with the fact that only a proportion of the estimated Extent of Occurrence is likely to be occupied, and may even be an overestimate given that densities are lower outside the Rivière Bleue valley (the species's stronghold) where the local population was estimated at 18 pairs by Létocart (pers. comm. 2000) in 1998. The estimate equates to 75-374 individuals in total, rounded here to 70-400 individuals.

Trend justification
There has been insufficient baseline monitoring of this species's population to empirically assess population trends. However, it was estimated to be comparatively common as recently as 2000 when the population was estimated at 1,000-3,000 individuals (Ekstrom et al. 2002). It seems likely that declines began prior to that period and may have increased since then; the most plausible threat being predation. For this reason a very rapid decline is suspected to be ongoing.

Ecology
It inhabits a humid forest/ maquis matrix, including small isolated forest patches, usually on ultrabasic soils, 100-850 m, historically in the hills to 1,000 m (Ekstrom et al. 2000), and has also been recorded in dry forests at Pouembout (S. Sirgouant verbally 1998, N. Barré in litt. 2003). It can be found up to 2 km from forest in the maquis scrub (Dutson 2011). It is an unobtrusive species seen singly or in pairs in the canopy or midstorey, feeding on invertebrates and nectar (Warner 1947, Ekstrom et al. 2000). Nests are built in open forests and are very poorly camouflaged, leaving them open to predation (Létocart 2006). Radio telemetry revealed that a pair (n-1) occupies a territory of 100 ha (Létocart 2006). Birds appear to maintain the same territory and from year to year nests appear to be situated close together in the core of the territory. Each simply constructed nest contains only a single egg or chick. No pair has been recorded producing more than one chick in a breeding season (R. Stirnemann in litt. 2012).


Threats
Forest loss and degradation caused by logging, nickel mining and fires is likely to be a threat (Ekstrom et al. 2000, Ekstrom et al. 2002), potentially having had a considerable impact in the côté oubliée from where the species now appears to be absent (V. Chartenrauldt in litt. 2009). The apparent decline at Rivière Bleue must be caused by other factors; with the species apparently subjected to severe predation pressure by introduced rats Rattus spp.(Ekstrom et al. 2002, N. Barré in litt. 2003, Létocart 2006) and possibly cats Felis catus (R. Stirnemann in litt. 2012). No successful nests or juvenile birds were seen until 2004 at Rivière Bleue, suggesting that the limiting factor affects its breeding success (Y. Létocart in litt. 1999). However, in 2004 and 2005, 2 chicks fledged successfully and were tracked visually for a few days. Nesting areas were heavily poisoned for rat population control which may explain the nesting success but another nest, found in 2005, and also in an area where rats were controlled failed with the chick disappearing during the first week (Létocart 2006). Other possible nest predators include native endemic predators such as New Caledonian Crow Corvus moneduloides and White-bellied Goshawk Accipiter haplochrous; nests are poorly camouflaged and presumably easy to locate (Létocart 2006). One of the 2 chicks visually monitored after fledging was usually moving between trees on the forest floor, this could mean that the species is also vulnerable to cats, dogs and pigs (Létocart 2006).


Conservation Actions Underway
Hunting and capture is prohibited. A breeding monitoring project conducted basic ecological research in the protected Parc Provincial Rivière Bleue from 2001 to 2005, including the radio-tracking of adults and video monitoring of nests (Y. Létocart in litt. 1999, Létocart 2006). Surveys were conducted in 2003-2006 by the Institut Agronomique néo-Calédonien (IAC) to establish the status of forest birds across New Caledonia (Chartendrault and Barré 2005, 2006). In 2010, the Société Calédonienne d'Ornithologie (SCO) conducted surveys in the Massif du Sud IBA in 17 areas identified as priority areas to survey for the species. A detailed assessment of the results is planned for 2011 to calculate density estimates for the area. Another project, undertaken at Mt Paine in the north of New Caledonia, resulted in the locating of the species in a site where it has not been documented for some years (M. O'Brien in litt. 2011, R. Stirnemann in litt. 2012)
Conservation Actions Proposed
Survey other localities within its extent of occurrence and keep searching for the species outside its known extent of occurrence. Urgently research basic habitat requirements, breeding ecology and success at Rivière Bleue. Investigate the presence of the species on Mont Panié Panié and Parc des Grandes Fougères. Further investigate the possibility of rat predation on nests. Research dispersal and subpopulation structure. Monitor numbers annually in two study sites in Rivière Bleue (Y. Létocart in litt. 1999, Ekstrom et al. 2000). Control rats close to nest sites and protect nesting trees from rats (in Rivière Bleue park at least). Increase the area of suitable habitat that has protected status. Develop a country-wide recovery plan for the species, including the establishment of captive breeding populations. Under take local conservation education programs.

References
Chartendrault, V.; Barré, N. 2006. Etude du statut et de la distribution des oiseaux des forêts humides de la province Sud de Nouvelle-Calédonie. Institut agronomique néo-calédonien, Port Laguerre, Nouvelle-Calédonie.

Collar, N. J.; Butchart, S. H. M. 2013. Conservation breeding and avian diversity: chances and challenges. International Zoo Yearbook.

Dutson, G. 2011. Birds of Melanesia: Bismarcks, Solomons, Vanuatu and New Caledonia. Christopher Helm, London.

Ekstrom, J. M. M.; Jones, J. P. G.; Willis, J.; Isherwood, I. 2000. The humid forests of New Caledonia: biological research and conservation recommendations for the vertebrate fauna of Grande Terre. CSB Conservation Publications, Cambridge, U.K.

Ekstrom, J. M. M.; Jones, J. P. G.; Willis, J.; Tobias, J.; Dutson, G.; Barre, N. 2002. New information on the distribution, status and conservation of terrestrial bird species in Grande Terre, New Caledonia. Emu 102: 197-207.

Létocart, Y. 2006. Synthèse des observations sur la nidification du Méliphage noir (Gymnomyza aubryana) dans le Parc Provincial de la Rivière Bleue (De 1980 à 2005).

Vuilleumier, F.; Gochfeld, M. 1976. Notes sur l'avifauna de Nouvelle-Calédonie. Alauda 44: 237-273.

Warner, D. W. 1947. The ornithology of New Caledonia and the Loyalty Islands. Thesis. Ph.D., Cornell University.

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
Benstead, P., Bird, J., Derhé, M., Dutson, G., Ekstrom, J., Harding, M., Mahood, S., Stattersfield, A.

Contributors
Barré, N., Chartendrault, V., Dutson, G., Ekstrom, J., Létocart, Y., Meresse, C., Meriot, J., O'Brien, M., Sirgouant, S., Spaggiari, J., Theuerkauf, J., Stirnemann, R.

Recommended citation
BirdLife International (2014) Species factsheet: Gymnomyza aubryana. Downloaded from http://www.birdlife.org on 22/12/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 22/12/2014.

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 Critically Endangered
Family Meliphagidae (Honeyeaters)
Species name author (Verreaux & Des Murs, 1860)
Population size 50-249 mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 1,100 km2
Country endemic? Yes
Links to further information
- Additional Information on this species