The Lord Howe woodhen (''Hypotaenidia sylvestris'') also known as the Lord Howe Island woodhen or Lord Howe (Island) rail, is a flightless

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

of the rail family, (Rallidae). It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found els ...

Lord Howe Island Lord Howe Island (; formerly Lord Howe's Island) is an irregularly crescent-shaped volcanic remnant in the Tasman Sea between Australia and New Zealand, part of the Australian state of New South Wales. It lies directly east of mainland ...

off the Australian coast. It is currently classified as

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...

by the IUCN.

Description

The Lord Howe woodhen is a small olive brown bird, with a short tail and a downcurved bill. Wings are chestnut with darker bars. The eyes have a red iris.

Ecology

The species lives in sub-tropical forests, feeding on

earthworm An earthworm is a terrestrial invertebrate that belongs to the phylum Annelida. They exhibit a tube-within-a-tube body plan; they are externally segmented with corresponding internal segmentation; and they usually have setae on all segments. ...

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean gro ...

s, fruit, and occasionally taking the eggs of

shearwater Shearwaters are medium-sized long-winged seabirds in the petrel family Procellariidae. They have a global marine distribution, but are most common in temperate and cold waters, and are pelagic outside the breeding season. Description These t ...

s and petrels. Woodhens mate for life and are usually encountered in pairs. They are territorial and will appear from the forest's understory to investigate the source of any unusual noise. A mated pair will defend an area of approximately three

hectare The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100- metre sides (1 hm2), or 10,000 m2, and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. An acre is ...

s, with offspring being expelled from this area once grown. The population of birds is thus restricted by the amount of available territory.

Decline and recovery

When explorers first discovered Lord Howe Island in 1788, they identified 15 bird species including the then common woodhen. Being flightless, curious, and having never been hunted, they became a readily available source of food for visiting sailors and the island's early human population. Since its discovery and the arrival of settlers on the island in 1834, nine of these 15 species became extinct. The woodhen declined in numbers until the late 1970s, when surveys showed that the population had dropped to less than 30 birds, confined to the difficult to access summit regions of the island's two mountains, Mount Gower and Mount Lidgbird. The woodhen was at the very brink of extinction in 1980, with just 15 individuals found. A comprehensive study was carried out to determine the cause of the decline, which was eventually attributed to the introduction of feral pigs. The elimination of the pigs and other disruptive animals (goats), plus a programme of ex-situ conservation (captive breeding) which commenced in May 1980 (the first egg was laid in June 1980), allowed the Lord Howe woodhen to recover its numbers. The captive breeding program was funded with $150,000 from the Foundation for National Parks & Wildlife, which was spent to construct the compound and to employ scientists involved in this project. In 2007–2008 there were about 250 birds on the island, which may be the optimal population size for this area. The population of adult birds in 2016 was 232. Following a successful rodent eradication on Lord Howe Island from 2019-2021, the woodhen population has increased significantly. A woodhen survey in 2021 found 598 birds, and in a further survey in March 2022 there were thought to be at least 779. The analysis of the threats to the Lord Howe woodhen, and the implemented solution, is considered a model for

conservation biology Conservation biology is the study of the conservation of nature and of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction and the erosion of biotic interactions. It is an ...

. A number of possible causes of the decline were identified on the island, from introduced

rat Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include ''Neotoma'' ( pack rats), ''Bandicota'' (bandicoot ...

s to Tasmanian masked owls. However, only the elimination of the pigs would have saved the species from

extinction Extinction is the termination of a kind of organism or of a group of kinds ( taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed ...

, and identifying the cause and solution in a timely manner was crucial to the success of the programme. Following success with the woodhen, there have been recovery efforts for other endemic species on Lord Howe Island, including the Lord Howe flax snail (''Placostylus bivaricosus'') and the Lord Howe currawong (''Strepera graculina crissalis'').

Gilbert rail

A rail, known only from a single specimen in the form of an alcohol-preserved skin at Harvard, was originally believed to have been collected on one of the

Gilbert Islands The Gilbert Islands ( gil, Tungaru;Reilly Ridgell. ''Pacific Nations and Territories: The Islands of Micronesia, Melanesia, and Polynesia.'' 3rd. Ed. Honolulu: Bess Press, 1995. p. 95. formerly Kingsmill or King's-Mill IslandsVery often, this n ...

and named as the Gilbert rail, ''Gallirallus conditicius'' (Peters & Griscom, 1928). However, the island attributed to this

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...

is low, rocky and sandy, and has no habitat suitable for a rail. It now appears that a curatorial error led to the specimen being labeled to the wrong collection, and the specimen is actually an immature female Lord Howe woodhen. It differs from that species only in a paler crown, throat and underparts, and browner head, but long immersion in alcohol could have changed the colour. The island to which the specimen was originally attributed is 4,500 km from Lord Howe Island, and it appears improbable that two flightless rails could evolve separately with no morphological differences.

References

External links

Image of an egg of a Lord Howe woodhen
(

Australian Museum The Australian Museum is a heritage-listed museum at 1 William Street, Sydney central business district, New South Wales, Australia. It is the oldest museum in Australia,Design 5, 2016, p.1 and the fifth oldest natural history museum in th ...

website) {{Taxonbar, from=Q687294 Hypotaenidia Birds of Lord Howe Island Endangered fauna of Australia Birds described in 1869 Flightless birds Taxa named by Philip Sclater