EN
Kagu Rhynochetos jubatus



Justification

Justification of Red List Category
This species has a very small population that is composed of small subpopulations and is inferred to be declining due to predation by dogs. It is suspected that it may be undergoing a rapid population reduction as a result of frequent predation events by dogs. For these reasons, it is classified as Endangered. However, population data are lacking. If better population data indicate that the overall population size is not undergoing a decline, the species may be downlisted to a lower category of threat in the future.

Population justification
Kagu has a skewed sex ratio, with 42% hatchlings being female (Theuerkauf et al. 2018). Additionally, only about half of all individuals are considered to be mature (J. Theuerkauf in litt. 2018). The proportion of mature individuals is therefore estimated to be 42% (50% multiplied by 84%). 

In Parc des Grandes Fougères, the population was estimated at over 1000 individuals in 2016, based on seven families followed by radiotracking, before the population underwent a reduction when two dogs killed half of all radio-tagged individuals over two months in 2017, resulting in over 75% of Kagu families in the park being destroyed (J. Theuerkauf in litt. 2016, 2018). The population in Parc des Grandes Fougères is therefore suspected to number 250-1,000 individuals.In Parc Provincial Rivière Bleue, 500 individuals were estimated in 2007, with an observed population reduction rate of c.20% every 4 years between 2002 and 2012 (J. Theuerkauf in litt. 2018). The population in Parc Provincial Rivière Bleue is suspected to number 256-500 individuals.

Surveys outside the aforementioned parks have estimated a population size of 491 mature individuals in 1991-1992, and 357 individuals in 2003-2006, but these figures may have been underestimates (Hunt 1996, Y. Létocart and C. Lambert in litt. 1999, J.-M. Mériot in litt. 2007). The population size on the remainder of the island is suspected to fall in the range 95-500 individuals. The total population size is therefore estimated at 601-2,000 individuals (rounded here to 600-2,000 individuals) and 252-840 mature individuals, here placed in the band 250 - 999 mature individuals.

Trend justification
The subpopulation in Parc des Grandes Fougères was estimated at over 1,000 individuals in 2016, but 75% of Kagu families in the park were destroyed when two dogs killed half of all radio-tagged individuals over two months in 2017 (J. Theuerkauf in litt. 2016, 2018). In Parc Provincial Rivière Bleue, the population was estimated at 500 birds in 2007, with an observed reduction of c.20% every 4 years between 2002 and 2012 as a result of predation by dogs (J. Theuerkauf in litt. 2018). Trends outside Parc des Grandes Fougère and Parc Provincial Rivière Bleue are not known, but it is suspected that predation by dogs may also be affecting population numbers elsewhere (J. Theuerkauf in litt. 2018). The species is therefore inferred to be undergoing a continuing decline in mature individuals. It is not known whether the overall population size has undergone a reduction over the past three generation, or whether it has undergone short-term declines followed by recoveries. Taking a precautionary approach, the overall rate of decline is placed in the band 50-79% across three generations and this rate of decline is projected to continue into the future.

Distribution and population

Rhynochetos jubatus is endemic to New Caledonia (to France), with subpopulations occurring in Parc des Grandes Fougère and Parc Provincial Rivière Bleue; a small number of individuals occur elsewhere on the island (Hunt 1996, Ekstrom et al. 2000, 2002). The largest recorded subpopulation is in Parc des Grandes Fougères, where surveys have shown an increasing population size, estimated at over 1000 individuals in 2016 (J. Theuerkauf in litt. 2016). However, in 2017, two dogs killed half of all radio-tagged individuals over two months, resulting in over 75% of Kagu families in the park being destroyed (J. Theuerkauf in litt. 2018). In Parc Provincial Rivière Bleue, the population was estimated at 500 birds in 2007, with fluctuating numbers, but a stable trend over the long term (J. Theuerkauf in litt. 2016). However, surveys between 2002 and 2012 observed a population reduction at a rate equivalent to 20% every four years as a result of predation by dogs (J. Theuerkauf in litt2018). Elsewhere, a survey of calling birds in 1991-1992 recorded 491 adults, 82% in Province Sud, and another survey conducted in 2003-2006 recorded 357 birds, but these figures may have been underestimates (Hunt 1996, Y. Létocart and C. Lambert in litt. 1999, J.-M. Mériot in litt. 2007). Field surveys by Chartendrault and Barré (2005, 2006) confirmed that kagus were still found in most of the areas previously surveyed by Hunt in 1992 (Hunt 1996, R. Gula and J. Theuerkauf in litt. 2012). Trends outside Parc des Grandes Fougère and Parc Provincial Rivière Bleue are not known, but it is suspected that predation by dogs may also be causing declines elsewhere (J. Theuerkauf in litt. 2018).

Ecology

The species inhabits a variety of forest-types, usually in humid forest with open understory, at mid-altitudes but ranges from sea-level to 1,400 m and also occupies drier forests at low altitude in the centre of the island (Boulouparis-La Foa area, from 100 m in the upper Ouenghi river) (Chartendrault and Barré 2005, 2006) and sometimes utilises closed-canopy scrub during the wet season (Hunt 1996, Létocart and Salas 1997). It feeds on earthworms, insects, snails and lizards (Létocart 1991). It has a cooperative, polyandrous breeding system; breeding clans consist of related males and unrelated females, with offspring remaining in the clan for up to ten years (Theuerkauf et al. 2009, 2018). It has a sex ratio bias of 42% (+/-12%) female hatchlings and 37% (+/-13%) female breeding individuals (Theuerkauf et al. 2018). Territories of neighbouring families can overlap, sometimes quite substantially (R. Gula in litt. 2016). Birds survive over 30 years in captivity (Y. Létocart and C. Lambert in litt. 1999), and at least 22 years in the wild (results from several radiotracked Kagus in the wild [R. Gula and J. Theuerkauf in litt. 2012]). The species breeds year-round, with eggs laid in every month except January and February (Barré et al. 2013). A recent study showed that Kagus are able to withstand much higher heavy metal concentrations than other birds worldwide (Theuerkauf et al. 2015).

Threats

The primary threat to the species is predation by stray hunting dogs. Dogs killed 17 out of 21 birds with radio-transmitters at Pic Ningua in 1993 (Hunt et al. 1996). In Parc des Grandes Fougères, two dogs killed half of radio-tagged individuals over two months in 2017, resulting in over 75% of Kagu families in the park being destroyed (J. Theuerkauf in litt. 2018). Such predation events appear to be regular (J. Theuerkauf in litt. 2018). In Parc Provincial Rivière Bleue, predation by dogs resulted in an observed population reduction rate of c.20% every 4 years between 2002 and 2012 (J. Theuerkauf in litt. 2018). One of these 20% reductions was caused by only one dog within six weeks (J. Theuerkauf in litt. 2018). Dogs have not established wild populations in New Caledonia, so predation by dogs occurs only near to human settlements (Rouys and Theuerkauf 2003). Predation by rats is a possible threat, although a long term study at Parc Provincial de la Rivière Bleue observed no incidents of predation by rats (Gula et al. 2010). Feral pigs occasionally take eggs (two out of 40 eggs and unlikely to be a significant threat [J. Theuerkauf in litt. 2007, S. Rouys in litt. 2008]) and forest floor rootings may make foraging for worms less easy (Hunt 1997, Létocart and Salas 1997, DDRP 1998, Y. Létocart in litt. 1999, Ekstrom et al. 2000). Introduced Rusa Deer Rusa timorensis are damaging forests in the Boulouparis - La Foa - Canala triangle, an important area for the species outside Rivière Bleue, and so may pose a threat to the species, although their impact on the species is unknown (Chartendrault and Barré 2005, 2006). Forest is being slowly eroded by mining and fires (Y. Létocart and C. Lambert in litt. 1999, Ekstrom et al. 2000, J. Ekstrom in litt. 2003), and logging aids access for hunters and dogs (Y. Létocart in litt. 1999, Ekstrom et al. 2000). However, an analysis of remotely-sensed data on forest loss found that the area of forest within the species's mapped range remained approximately stable between 2000 and 2012 (Tracewski et al. 2016). Disease in the Rivière Bleue may be a severe threat in the future (Chartendrault and Barré 2005, 2006)At least 15% of the individuals surveyed at Rivière Bleue during the 2006 breeding season died, perhaps due to disease (J. Theuerkauf in litt. 2007).

Conservation actions

Conservation Actions Underway

CITES Appendix I. A Kagu Species Action Plan (PASC) which spans the period 2009-2020 was compiled in 2008 (SCO 2008). It occurs in Parc des Grandes Fougère and Parc Provincial Rivière Bleue. A population is protected in Reserve Speciale de Faune et de Flore de la Nodela, but without wardening or dog control (Ekstrom et al. 2000). Dogs are controlled in Rivière Bleue (Létocart 1991, Hunt et al. 1996). Legislation and education aims to reduce capture by hunting dogs, but incidental killings are difficult to control (Hunt et al. 1996). Birds have been successfully bred in captivity since 1978, and reintroduced to protected areas (Bregulla 1987). The population in Parc des Grandes Fougères has been monitored since 2011 (J. Theuerkauf in litt. 2016). A pilot study on the behaviour of wandering dog tribes was initiated in 2013 in Massif des Lèvres (L'Oiseau 2014).

Conservation Actions Proposed

Monitor the population size, trends and distribution. Survey poorly-known forest areas. Assess the genetic status of the population. Evaluate fragmentation and gene flow between subpopulations with molecular methods (Stoeckle et al. 2012). Investigate dispersal between isolated populations. Determine effects of rat predation at different sites, particularly in the north. Ascertain effects of deer. Investigate possibilities of deer population control in some important areas. Control dogs and cats in key forest sites. Conserve and manage key sites including Parc des Grandes Fougère and Parc Provincial Rivière Bleue. Maintain and restore connections between sites where the species occurs (SCO 2008). Increase public awareness programmes regarding Kagu conservation and responsible dog ownership. Consider reintroducing the species at Panié mountain (SCO 2008).

Identification

55cm. Ghostly-grey bird, belonging to a monospecific family. Flightless. Uniform plumage contrasts with orange-red bill and legs. Long shaggy crest erected in display. Spread wings expose prominent black-and-white barring. Similar spp. Unmistakable; heron species are rarely found in forest and none has uniform grey plumage or red bare parts. Voice Loud barking at dawn and various quiet hissing and rattling calls. Hints Usually seen stationary or walking slowly in shaded forest. Locally common in Rivière Bleue: permits and advice can be obtained at the entrance gate.

Acknowledgements

Text account compilers
Wheatley, H., Stattersfield, A., Westrip, J., Dutson, G., Ekstrom, J., Derhé, M., Benstead, P., Mahood, S.

Contributors
Chartendrault, V., Ekstrom, J., Gula, R., Lambert, C., Létocart, Y., Mériot, J.-M., Rouys, S. & Theuerkauf, J.


Recommended citation
BirdLife International (2020) Species factsheet: Rhynochetos jubatus. Downloaded from http://www.birdlife.org on 18/01/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 18/01/2020.