Hypotaenidia sylvestris 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Gruiformes Rallidae

Scientific Name: Hypotaenidia sylvestris
Species Authority: (Sclater, 1869)
Common Name(s):
English Lord Howe Woodhen, Lord Howe Island Woodhen, Lord Howe Rail, Lord Howe Wood Rail
Spanish Rascón de Isla Lord Howe
Gallirallus sylvestris (Sclater, 1869)
Tricholimnas sylvestris Collar and Andrew (1988)
Taxonomic Source(s): del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Lynx Edicions BirdLife International.
Taxonomic Notes: Gallirallus conditicius (Sibley and Monroe 1990, 1993), known only from the type reputedly collected in the Apiang Group of the Gilbert Islands, Kiribati, in 1861, is not recognised as a separate species but is treated as a synonym of H. sylvestris (Greenway 1952, Olson 1992).

Hypotaenidia sylvestris (del Hoyo and Collar 2014) was previously placed in the genus Gallirallus.

Identification information: 34-42 cm (male), 32-37 cm (female). Large, olive-brown, flightless rail with bright chestnut wings. Olive-brown body, duller on underside. Indistinct, paler supercilium. Bright chestnut wings with narrow, dark brown bars on primaries and primary coverts. Long, decurved, pink bill, more brown towards tip. Red iris. Light pink-brown legs. Juvenile similar, but iris initially dark. Similar spp. Confusion unlikely. Buff-banded Rail G. philippensis is smaller, has bold black-and-white barring on underside, buff breast-band and clear white supercilium. Voice Loud, piercing, repeated whistle, often as duet. Hints Confiding. Spreads wings to sunbathe.

Assessment Information [top]

Red List Category & Criteria: Endangered D ver 3.1
Year Published: 2013
Date Assessed: 2013-11-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S.
Contributor(s): Carlile, N.
Facilitator/Compiler(s): Garnett, S., McClellan, R., Pilgrim, J., Stattersfield, A., Taylor, J., Allinson, T & Symes, A.
This species is listed as Endangered as it has an extremely small population which is restricted to a tiny area of available habitat on one island. Conservation efforts have resulted in the stabilisation of numbers.

Previously published Red List assessments:
2012 Endangered (EN)
2008 Endangered (EN)
2006 Endangered (EN)
2004 Endangered (EN)
2000 Endangered (EN)
1996 Endangered (EN)
1994 Endangered (EN)
1988 Threatened (T)

Geographic Range [top]

Range Description: Hypotaenidia sylvestris is endemic to Lord Howe Island (Australia). In 1788, it was found from sea-level to the tops of the two mountains on the island, but from the mid-19th century, it became restricted to the summits. In the 1970s the population comprised fewer than 10 breeding pairs (Brook et al. 1997). In the 1980s, following the eradication of introduced pigs Sus domesticus, birds were reintroduced to lowland sites, including isolated, steep, coastal palm forest at Little Slope, and lowland palm forests around the settlement. The highest densities are now surrounding the settlement and on Mt Gower, which support over half of the population. The population has reached the island’s carrying capacity (estimated at c.220 individuals [Brook et al. 1997]) and was estimated to be stable at around 220–230 birds and 71–74 breeding pairs (NSW National Parks and Wildlife Service 2002).

Countries occurrence:
Estimated area of occupancy (AOO) - km2: 2
Continuing decline in area of occupancy (AOO): Unknown
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) - km2: 2
Continuing decline in extent of occurrence (EOO): Unknown
Extreme fluctuations in extent of occurrence (EOO): No
Number of Locations: 1
Continuing decline in number of locations: Unknown
Extreme fluctuations in the number of locations: No
Upper elevation limit (metres): 800
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The population has recovered to the island's carrying capacity (estimated at c.220 individuals [Brook et al. 1997]) and was estimated to be stable at around 220–230 birds and 71–74 breeding pairs (NSW National Parks and Wildlife Service 2002).

Trend Justification:  The total population has stabilised at c.130 mature birds (Garnett and Crowley 2000).
Current Population Trend: Stable
Additional data:
Number of mature individuals: 140 Continuing decline of mature individuals: Unknown
Extreme fluctuations: No Population severely fragmented: No
No. of subpopulations: 1 Continuing decline in subpopulations: Unknown
Extreme fluctuations in subpopulations: No All individuals in one subpopulation: Yes
No. of individuals in largest subpopulation: 100

Habitat and Ecology [top]

Habitat and Ecology: Gallirallus sylvestris is sedentary, flightless and confined to closed forest. At high altitudes, it occurs in gnarled, mossy forest which covers, and is unique to, the mountain summits. It is largely found in megaphyllous, broad sclerophyll forest at lower altitudes, particularly kentia palm Howea forsterana growing on igneous soils. It is rarely found in the rainforest subformation that covers most of the island. It nests on the ground under thick vegetation or in petrel burrows, and forages among the litter on the forest floor, taking worms, molluscs, invertebrates and occasionally petrel nestlings.

Systems: Terrestrial
Continuing decline in area, extent and/or quality of habitat: Unknown
Generation Length (years): 3.4
Movement patterns: Not a Migrant

Threats [top]

Major Threat(s): The species was eliminated from the lowlands by predation by feral pigs, cats, people and their dogs, as well as disturbance by pigs and goats. These threats were largely eliminated in the 1980s, although uncontrolled pet dogs can still be an occasional problem. The only remaining significant threat is the introduced Masked Owl Tyto novaehollandiae which is thought to be responsible for a major decline in the Little Slope population in 1989. Further introductions of exotic predators or the introduction of chronic disease could have serious consequences (Taylor and van Perlo 1998). Buff-banded Rails Hypotaenidia philippensis have re-colonised the island and may conflict with Woodhens, especially during the breeding season (Garnett et al. 2011). Woodhens are likely to be in danger of accidental poisoning during the planned eradication of black rats, which is why it is planned to take as many as possible into captivity while the baits are toxic (Lord Howe Island Board 2009). Natural catastrophes are an additional threat. Population Viability Analysis using VORTEX suggests that the species remains highly susceptible to changes in survival or fecundity (Brook et al. 1997).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
CITES Appendix I. The species is successfully bred in captivity. Predation and disturbance by dogs is minimised by community support for conservation efforts. Goats and pigs have been eradicated.

Conservation Actions Proposed
Monitor trends in the population. Control T. novaehollandiae. Develop captive breeding programmes and establish a remote population to minimise the risk of extinction (Taylor and van Perlo 1998). Implement measures to prevent further introductions of exotic predators to Lord Howe Island.

Citation: BirdLife International. 2013. Hypotaenidia sylvestris. The IUCN Red List of Threatened Species 2013: e.T22692395A47998449. . Downloaded on 30 November 2015.
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