Ornithol Sci 18: 169 – 175 (2019)

REVIEW ARTICLE Preventing the of the ( sylvestris) through predator eradication and population augmentation

Dean PORTELLI1 and Nicholas CARLILE2,#

1 Department of Environment and Natural Resources, P.O. Box 1120, Alice Springs, NT, 0871 Australia 2 Office of Environment and Heritage, P.O. Box 1967, Hurstville, NSW, 2220 Australia

ORNITHOLOGICAL Abstract The Lord Howe Woodhen (Hypotaenidia sylvestris) is endemic to off the mid-east coast of Australia and came perilously close to extinc- SCIENCE tion as a result of hunting pressure and introduced predators. A recovery program was © The Ornithological Society implemented in the 1970s to reverse the decline of the species through eradicating of Japan 2019 introduced predators (, cats and goats) and augmenting the population through an in situ captive-breeding program. In 1980, three wild breeding pairs were taken into captivity from Mount Gower. Over the four years of the captive-breeding program, 76 chicks were produced from the original founders and their progeny and an additional four chicks were artificially reared from eggs collected from a wild pair. Almost all woodhens were liberated across four release sites, but only 13% of released were resighted and numbers increased at only one of these sites and then declined. A captive-bred female that was released into the lowlands paired with a wild male (which had been temporarily held in captivity) and bred prolifically, leading to rapid population growth in the lowlands. The subpopulation on Mount Gower increased fivefold in the decade following the captive-breeding program, despite the removal of the three breeding pairs (which were released elsewhere) and receiving no aug- mentation from the captive-breeding program. The woodhen population continues to expand and it is likely the eradication of invasive rodents from Lord Howe Island during 2019 will facilitate further population growth.

Key words Rallidae, , , recovery program

LORD HOWE ISLAND main island and its surrounding islets support 239 species of indigenous plants, with 113 endemic spe- Lord Howe Island is a crescent-shaped volcanic cies (DEC 2006). Endemism is similarly high among remnant located in subtropical waters 580 km off the the 1,608 invertebrate species identified from the mid-east coast of Australia. It has extensive shallow island group (Cassis et al. 2003). The island group’s coral reefs enclosed in a lagoon on the western side, native mammalian fauna comprises one extant and and is surrounded by several offshore islets, includ- one extinct microbat species (Duncan et al. 1999). ing Balls Pyramid (551 m) situated 23 km to the Like many islands worldwide, Lord Howe Island has south. Lord Howe Island is 11 km long, covers 1,455 experienced numerous since people ha and comprises two eroded volcanic peaks reaching first visited the island: three endemic species and 875 m (Mount Gower) and 771 m (Mount Lidgbird) five endemic subspecies have become extinct (Hutton in the south; a series of flats and lower hills in the 1991). Eighteen resident terrestrial bird species and middle (the lowlands); and a range of hills rising 14 migratory seabirds currently breed within the to 209 m in the north, which are the remains of a island group (Hutton 1991). This includes the Lord caldera shield (McDougall et al. 1981; Fig. 1.). The Howe Woodhen (Hypotaenidia sylvestris; hereafter woodhen), which is an endemic species that came perilously close to extinction and is currently clas- (Received 25 May 2017; Accepted 10 April 2019) # Corresponding author, E-mail: Nicholas.Carlile@environment. sified as Endangered by the IUCN (Birdlife Interna- nsw.gov.au tional 2016).

169 D. PORTELLI and N. CARLILE

(see Olson 1973), but later revisions to the of the Rallidae confirmed the woodhen belonged to the widespread genus Gallirallus (Kirchman 2012, García-R et al. 2016). The taxonomy of Gallirallus was revised by del Hoyo and Collar (2014), who placed the woodhen in a new genus, Hypotaenidia, along with nine other species. The male woodhen can be readily distinguished from the female by its larger size and more upright stance (Miller & Mullette 1985). They are monogamous and territo- rial, breed mostly during late spring to early summer, lay clutches of 1–4 eggs, and are capable of rearing more than one brood per year (Miller & Kingston 1980, Miller & Mullette 1985).

POPULATION DECLINE AND ITS CAUSES From the discovery of the island in 1788 until it was first settled in the early 1830s, the woodhen was reportedly abundant (Table 1) and readily har- vested in large numbers by passing sailors (Miller & Kingston 1980; Frith 2013). Although historical accounts of the size of the woodhen population are anecdotal, it had declined substantially by the mid- 19th century, and as early as the 1880s its extinction was considered imminent (Miller & Kingston 1980; Frith 2013). Collectors failed to obtain woodhen Fig. 1. Distribution of Lord Howe Woodhen. Shaded areas specimens in 1853 despite an extensive stay on the indicate where woodhens were recorded during annual sur- island (MacDonald in Hindwood 1940). Moreover, veys between 2008 and 2015 (Lord Howe Island Board scientists and an eminent ornithologist struggled, or unpublished). Black circles indicate localities where woodhen failed, to locate the species in the late 1880s and occur outside the area surveyed each year. Stars indicate the early 1900s (Frith 2013). By 1936, the species was approximate location of the four main release sites (white confined largely to the rugged upper slopes and pla- stars) and the site where a captive-bred female was released teaus of the two southern mountains (Hindwood and paired with a wild male (black star). Contour intervals are 1940). From 1971, surveys estimated the surviv- spaced 20 metres apart. The lowlands are located either side of the airstrip. ing population of woodhen on Mount Gower num- bered 22 individuals, including only eight breeding pairs (Disney 1972; Fullagar & Disney 1975), with DISCOVERY AND DESCRIPTION OF THE a further 3–5 pairs estimated from the summit of LORD HOWE WOODHEN Mount Lidgbird (Fullagar & Disney 1975). By the late 1970s, only ten pairs were found on the summit The woodhen is a medium-sized (mean adult body and slopes of Mount Gower, two birds (both male) mass: 536 g male, 456 g female), dull olive brown, on Mount Lidgbird and a single bird in the lowlands flightless rail, with a long recurved bill, short tail, (Miller & Mullette 1985). The dire state of the popu- and chestnut flight feathers that are finely barred lation was well-established, but the efforts required black (Marchant & Higgins 1993). The first men- to reverse the decline were unclear due to unknown tion of the species was in 1788 (Miller & Kingston risks and costs (Recher & Clarke 1974). 1980), but it wasn’t formerly described until 1869 The dramatic decline of the woodhen was attrib- when Sclater named it Ocydromus sylvestris (Sclater uted to several factors; however, the relative impor- 1869). The woodhen was traditionally placed in the tance of each in driving the species towards extinc- genus Tricholimnas with the New Caledonian Rail tion is unclear. Anthropogenic impacts began with

170 Preventing the extinction of the Lord Howe Woodhen

Table 1. Chronology of events for the Lord Howe Woodhen 1788 to 2018.

Date and event Impact on woodhens and population status 1788 humans first visit Lord Howe Island Harvested for food. Woodhen common across island Early to mid-1800s feral and goat populations estab- Presumed predation by pigs. Habitat degraded by pigs and goats lished 1830s to 1850s human settlement and arrival of domestic Harvested for food. Predation by dogs and cats within settled dogs and cats areas. Woodhen remain common outside of settlement 1918 black colonise island from beached trading ship Impact of rats unclear 1936 visit to island by ornithologist Woodhens restricted to southern mountains Early 1970s first woodhen surveys 11–13 woodhen pairs remaining 1976 eradication of feral cats commenced 1979 eradication of pigs commenced Late 1970s woodhen resurveyed 10 woodhen pairs remaining 1980 woodhen captive-breeding program commenced Three woodhen pairs removed from Mount Gower to captive- breeding centre Early 1982 woodhen pair commence breeding at Salmon Woodhens increase in number and spread from Salmon Beach Beach into adjoining settlement 1982 cat eradication ceased, and ownership regulated Feral cat population eradicated and importation and breeding of domestic cats banned 1984 woodhen captive-breeding program ceased 81 woodhens released over 4 seasons across the lowlands and mountain slopes (no woodhens released on mountains) 1985 pig eradication program ceased Pig population effectively eradicated (one boar remaining) 1985 annual woodhen surveys commenced 11 woodhens counted on Mount Gower plateau 1988 woodhen survey 92 woodhens counted in settlement 1995 woodhen survey 55 woodhens counted on Mount Gower plateau 1999 eradication of goats commenced Goat population effectively eradicated (only three females present by 2012) 2002 woodhen survey 127 woodhens counted across accessible areas 2018 woodhen survey 221 woodhens counted across accessible areas hunting of woodhens for food by sailors and early indicates they were not the sole cause of the decline. settlers (Miller & Kingston 1980; Frith 2013). The Cats (Felis catus) were first brought onto the island introduction of several mammals to the island exacer- in the early to mid-1800s and subsequently estab- bated the decline. Pigs (Sus scrofa) were released on lished a feral population (Miller & Mullette 1985). the main island in ~1800 to provide a source of meat The impact of cat predation is poorly documented, for passing sailors and became widespread over the but it was probably partly responsible for the wood- southern half of the island (Miller & Mullette 1985). hen decline in the northern half of the island (NSW Pigs disturbed the forest floor where woodhens for- NPWS 2002). Predation by domestic dogs (Canis age, probably competed with woodhens for food, and lupus familiaris) may have also reduced woodhen were presumed to prey on woodhens and/or their numbers in the lowlands (Miller & Kingston 1980; eggs (Miller & Kingston 1980; Miller & Mullette Frith 2013). Habitat degradation by feral goats 1985). The most compelling evidence for the role (Capra aegagrus hircus) (Pickard 1976) apparently pigs played in contributing to the decline of wood- eliminated the woodhen from one pocket of forest hens was their respective distributions: by the late where it was protected from pigs and cats (Miller & 1970s, woodhens were confined to areas where pigs Mullette 1985). Despite early concerns (McCulloch were absent (Miller & Mullette 1985). However, the 1921), there is no evidence the introduction of black absence of pigs from the lowlands and northern hills rats (Rattus rattus) to the island in 1918 contributed

171 D. PORTELLI and N. CARLILE to the woodhen’s decline (Miller & Mullette 1985). cess and was subsequently released at Salmon Beach (Frith 2013). Over the four seasons of the breeding program THREAT ABATEMENT AND CAPTIVE (1980–84), six woodhen pairs produced 76 surviv- BREEDING ing chicks (1–30 per pair) from 68 clutches (Lourie- A recovery program was implemented in the 1970s Fraser 1985 in Frith 2013). Most chicks were artifi- with two elements: the eradication of predatory mam- cially reared from eggs, which increased the number mals, and population augmentation through captive of clutches laid per year by the captive breeding pairs breeding and release of woodhen back into the wild. (Lourie-Fraser 1983, Miller & Mullette 1985). Four The eradication of feral pigs commenced in April additional chicks were reared in artificial incubators 1979 and at least 200 pigs were killed over the next from eggs collected from deserted clutches of a wild six years (Miller & Mullette 1985; Fullagar 1985); pair that formed when a captive bred female paired a single adult male remained but is now presumed with a wild male (see below; Miller & Mullette dead (NSW NPWS 2002). A shooting and trapping 1985). Two additional captive woodhen pairs laid 17 program began in 1976 to eradicate feral cats, with clutches, but all eggs were infertile (Lourie-Fraser over 80 individuals killed in the first two years and 1985 in Frith 2013). a further four by 1980 (Miller & Mullette1985). By 1982 the feral cat population was extinct, the impor- WILD RELEASES AND POPULATION tation of cats was banned, and all domestic cats kept GROWTH in island households were required to be desexed (DEC NSW 2006). The last domestic cat died in 2009 All woodhen successfully reared in captivity were (Nicholas Carlile unpublished). In 1999, the eradica- released over the four years of the program (1980– tion of feral goats commenced to conserve the native 1984) along with the surviving wild-caught birds vegetation communities on the island (Parkes et al. (Miller & Mullette 1985). Most releases (81 individ- 2011). In that year, 295 goats were shot from either uals) occurred across four main release sites within a helicopter or on the ground. One additional and near the southern mountains, with 7–36 birds was shot in 2001 (Parkes et al. 2011), and by 2002 released at each site (Miller & Mullette 1985). A only a few non-reproductive individuals remained soft-release strategy was initially employed, whereby (NSW NPWS 2002). woodhen were kept in 100 m2 roofed pens at the As the population of woodhens had become per- release site for two weeks before release (Miller & ilously low by the late 1970s, a captive breeding Mullette 1985). Once a population was established program was established to increase the wild popula- at the first release site (Little Slope), woodhen were tion through releasing captive-bred birds. An in situ released directly into the wild (Miller & Mullette breeding program was chosen to minimise transport 1985). Systematic surveys commenced in 1985 to times to and from the wild, changes in environmental monitor the woodhen population through counting conditions experienced by captive birds, and the risk birds along permanently marked transects and in resi- of disease (Miller & Mullette 1985). A facility was dential properties (Harden 1986). All woodhens were established within the island’s lowlands in 1980, and captured and banded with an individually unique initially comprised three breeding aviaries and two combination of colour bands (Harden 1986). In the holding aviaries, with a further three breeding aviar- years following release, the number of woodhens ies added in 1981 (Lourie-Fraser 1983). In mid-1980, increased at only one of the main release sites (Little three territory-holding pairs from the Mount Gower Slope), reaching a peak of 40 individuals (from 22 plateau, which were the only healthy pairs remain- released), but it rapidly declined to 8–10 birds by ing there, were captured and transported by helicop- 1990 (Bob Harden et al. unpublished). Only a few ter to the lowlands where they were released into isolated pairs became established at the other three the aviaries (Miller & Mullette 1985). Two young, sites (Bob Harden et al. unpublished) where the habi- unpaired males were captured in the second year to tat was possibly suboptimal (Bob Harden personal replace a male that was killed by a Masked Owl (Tyto communication). Overall, only 13% of the woodhens novaehollandiae) in the first season, but one was later released were subsequently resighted (Bob Harden et released (Lourie-Fraser 1983). One of the original al. unpublished). The greatest growth in the popula- breeding pairs experienced poor reproductive suc- tion occurred in the lowlands of the island, where

172 Preventing the extinction of the Lord Howe Woodhen the number of woodhens rapidly rose to 92 by 1988, the recovery of the population, particularly the spread evidently because of prolific breeding by a single of woodhens across the island. pair of birds and their progeny (Miller & Mullette The knowledge and husbandry techniques devel- 1985; Harden 2002). This pair was formed when a oped during the captive breeding program are now captive-bred female was released in the territory of a being used to further the ecological restoration of lone wild male at Salmon Beach in November 1981 Lord Howe Island. A program to eradicate introduced (Miller & Mullette 1985; Frith 2013). Despite the black rats and house mice (Mus musculus) from the removal of nine birds from the Mount Gower plateau island group (Wilkinson & Priddel 2011) will be to establish the captive population, the number of implemented in the austral winter of 2019 (Walsh et woodhens on the plateau increased fivefold within a al. 2019). Following protocols established for other decade from 11 individuals in 1985 (Harden 2002; no successful island rodent eradications (Cromarty et al. woodhens were released on the plateau). Population 2002), cereal baits laced with brodifacoum will be monitoring has continued to the present; although distributed across the island by hand and helicopter the methodology was changed in 1990 from transect (Lord Howe Island Board 2009). Such baiting poses counts to a direct census of woodhens occupying a serious risk to the woodhen as they readily con- accessible parts of the island (Harden 1999). In April sume cereal baits (Wilkinson & Priddel 2007) and are 2002, 127 individuals were counted from accessible susceptible to brodifacoum-induced toxicosis (Lord areas, excluding Little Slope (NSW NPWS 2002). Howe Island Board unpublished). Accordingly, the In November 2018, a similar survey recorded 212 capture and temporary confinement in captivity of individuals (Lord Howe Island Board unpublished). a substantial proportion of the woodhen population Woodhen are currently found primarily in gnarled is a condition of the eradication plan (Lord Howe mossy forest, megaphyllous broad sclerophyll for- Island Board 2009). To determine whether woodhen est–primarily the Kentia Palm (Howea forsteriana) could be housed in groups for extended periods (up association growing within or downslope of soils to 100 days while the bait is accessible), a trial was derived from igneous geology–and residential gar- completed in July–September 2013 (Taronga Zoo dens (Harden & Robertshaw 1989; NSW NPWS 2014). This involved housing twenty adult woodhens 2002). Approximately 75% of the island is still cov- for three months in a single, purpose-built 15 m by ered in native vegetation and is now protected within 15 m enclosure within an enclosed outdoor green- a Permanent Park Preserve (NSW NPWS 1986). In house. All woodhens maintained their body condi- 1982, Lord Howe Island was inscribed on the World tion on a mixed diet of natural and artificial foods Heritage List (UNESCO 1982), thereby affording and close monitoring confirmed they tolerated liv- further protection to woodhen habitat. ing in a group; all were returned in good health to their original territories (Taronga Zoo 2014). It is anticipated the removal of rodents will result in an CONCLUDING REMARKS AND FUTURE increase in invertebrate biomass (see Sinclair et al. MANAGEMENT 2005), which will be bolstered by the reintroduction The conservation of the woodhen is one of the most of select invertebrate species (Priddel et al. 2003; successful projects undertaken to reverse the decline Carlile et al. 2018). This expected increase in prey of a threatened Australian vertebrate (Caughley & availability for woodhens will likely increase the car- Gunn 1996). Indeed the rapidity with which the pop- rying capacity of the island, leading to further popu- ulation recovered was remarkable. The strong capac- lation growth and add another chapter to this highly ity of the woodhen population to recover, provided successful conservation program. threats have been abated, was demonstrated by the rapid growth of the subpopulation on the plateau ACKNOWLEDGMENTS of Mount Gower. Records of colour-banded birds indicate that this subpopulation was not augmented Much of this review has relied on previously by captive-bred birds or their progeny (Bob Harden published papers and unpublished reports from the et al. unpublished). Therefore, whether the captive recovery period, but it also draws from the unpub- breeding program was necessary to achieve popula- lished work of Bob Harden, John Robertshaw, David tion recovery is questionable. Nonetheless, popula- McFarland and Justin Billing. The collection of con- tion augmentation using captive-bred birds hastened temporary data (since 2000) draws primarily on the

173 D. PORTELLI and N. CARLILE efforts of Christo Haselden and staff of the Lord Fullagar PJ (1985) The Lord Howe Island Woodhen Howe Island Board and we are grateful to them for Project. Aviculture Magazine 91:15–30. providing access to those data. Fullagar PJ & Disney HJ de S (1975) The Birds of Lord Howe Island: A report on the rare and . Bulletin of the International Council for Bird REFERENCES Preservation 12: 187–202. BirdLife International (2016) Hypotaenidia syl- García-R JC, Elliott G, Walker K, Castro I & Trewick vestris. The IUCN Red List of Threatened Spe- SA (2016) Trans-equatorial range of a land bird lin- cies 2016: e.T22692395A93352096. Available at eage (Aves: Rallidae) from tropical forests to subant- http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS. arctic grasslands. J Avian Biol 47: 219–226. T22692395A93352096.en (accessed on 1 July 2016). Harden R (1986) Lord Howe Island Woodhen census Carlile N, Priddel D & O’Dwyer T (2018) Abundance, 1985. Unpubl. Report. Scientific Services Section, distribution and ecology of the endangered Lord NSW National Parks and Wildlife Service, Hurstville, Howe Island wood-feeding cockroach Panesthia New South Wales. lata (BLATTODEA: BLABERIDAE) on two islands Harden R (1999) Methods used in the census of the within the Lord Howe Group. Austral Entomol 57: Lord Howe Island Woodhen population from 1985 207–213. to 1998. Unpubl. Report. Biodiversity Survey and Cassis G, Meades L, Reid C, Harris R, Carter G & research Division, National Parks and Wildlife Ser- Jeffreys E (2003) Lord Howe Island: Terrestrial vice, Hurstville, New South Wales. Invertebrates Biodiversity and Conservation. A report Harden R (2002) Recent trends in the number of wood- prepared by the Australian Museum Centre for Biodi- hen recorded during surveys. Unpubl. Report. Bio- versity and Conservation Research for NSW National diversity Research and Management Division, NSW Parks and Wildlife Service. Australian Museum, National Parks and Wildlife Service, Hurstville, New Sydney. South Wales. Caughley G & Gunn A (1996) Harden R & Robertshaw J (1989) Lord Howe Island in Theory and Practice. Blackwell Science, Oxford. Woodhen census 1988. Unpubl. Report. Environmen- Cromarty PL, Broome KG, Cox A, Empson RA, tal Survey and Research Branch, NSW National Parks Hutchinson WM & McFadden I (2002) Eradication and Wildlife Service, Hurstville, New South Wales. planning for invasive alien animal species on islands- Hindwood KA (1940) The birds of Lord Howe Island. the approach developed by the New Zealand Depart- Emu 40: 1–86. ment of Conservation. In: Veitch CR & Clout MN Hutton I (1991) Birds of Lord Howe Island: Past and (eds) The eradication of invasive species. pp 85–91. present. The Author, Coffs Harbour, New South Wales. IUCN, Gland, Switzerland. Kirchman JJ (2012) Speciation of flightless rails on del Hoyo J & Collar NJ (2014) HBW and BirdLife islands: A DNA-based phylogeny of the typical rails International Illustrated Checklist of the Birds of of the Pacific. Auk 129: 56–69. the World Volume 1: Non-passerines. Lynx Edicions, Lord Howe Island Board (2009) Draft Lord Howe Barcelona. Island Rodent Eradication Plan. Lord Howe Island Department of Environment and Conservation (NSW) Board, Lord Howe Island. (2006) Biodiversity Management Plan for Lord Howe Lourie-Fraser G (1983) Captive breeding of the Lord Island. Department of Environment and Conservation Howe Island woodhen: an endangered rail. The Am (NSW), Sydney. Fed Avicul Watch 10: 30–44. Disney HJ de S (1972) Lord Howe Island Woodhen Marchant S & Higgins PJ (1993) Handbook of survey. In: Recher HF (ed) A report to the Lord Howe Australian, New Zealand and Antarctic birds. Volume Island Board on an environmental survey of Lord 2: Raptors to lapwings. Oxford University Press, Howe Island. Unpublished report of the Australian Melbourne. Museum, Sydney. McCulloch AR (1921) Lord Howe Island- A naturalist’s Duncan A, Baker GB & Montgomery N (1999) The paradise. Australian Museum Magazine 1(2): 31–47. Action Plan for Australian Bats. Environment Australia, McDougall I, Embleton BJJ & Stone DB (1981) Ori- Canberra, Australia. gin and evolution of Lord Howe Island, Southwest Frith CB (2013) The Woodhen: A flightless island Pacific Ocean. J Geol Soc Aust 28: 155–176. bird defying extinction. CSIRO Publishing, Victoria Miller B & Kingston T (1980) Lord Howe Island Wood- Australia. hen. Parks and Wildlife August 1980:17–26. Miller B & Mullette KJ (1985) Rehabilitation of an

174 Preventing the extinction of the Lord Howe Woodhen

endangered Australian bird: Lord Howe Woodhen Zool Soc Lond 472–473. Tricholimnas sylvestris. Biol Conserv 34: 55–95. Sinclair L, McCartney J, Godfrey J, Pledger S, Wakelin NSW NPWS (1986) Permanent Park Preserve Plan M & Sherley G (2005) How did invertebrates of Management. NSW National Parks and Wildlife respond to eradication of rats from Kapiti Island, Service, Hurstville. New Zealand? New Zeal J Zool. 32: 293–315. NSW National Parks and Wildlife Service (2002) Taronga Zoo (2014) Captive management for Woodhen Approved Recovery Plan for the Lord Howe Wood- and LHI Currawong associated with the Lord Howe hen. NSW National Parks and Wildlife Service, Island Rodent Eradication project. Unpublished Hurstville, NSW. report to the Lord Howe Island Board, 2014. Olson SL (1973) A classification of the Rallidae. Wilson UNESCO (1982) Nominations to the World Heritage Bull 85: 381–416. List (inscribed sites). Available at http://whc.unesco. Parkes JP, McDonald N & Leaman G (2011) An attempt org/en/decisions/5276 (accessed on 30 June 2016). to eradicate feral goats from Lord Howe Island. In: Walsh A, Wilson A, Bower H, McClelland P & Pearson Veitch CR, Clout MN & Towns DR (eds) Island J (2019) Winning the hearts and minds – proceeding Invasives: Eradication and Management. pp 233– to implementation of the Lord Howe Island rodent 239. IUCN, Gland, Switzerland. eradication project: a case study. In: Veitch CR, Clout Pickard J (1976) The effect of feral goats, Capra hircus MN, Martin AR, Russell JC & West CJ (eds) Island L., on the vegetation of Lord Howe Island. Aust J invasives: scaling up to meet the challenge. pp 522– Ecol 1: 103–13. 530. IUCN, Gland, Switzerland. Priddel D, Carlile N, Humphrey M, Fellenberg S & Wilkinson IS & Priddel D (2007) Report on non-toxic Hiscox D (2003) Rediscovery of the ‘extinct’ Lord bait trials Lord Howe Island – August 2007. Unpub- Howe Island stick-insect (Dryococelus australis lished report to the Lord Howe Island Board, Lord (Montrouzier)) (Phasmatodea) and recommendations Howe Island, New South Wales. for its conservation. Biodivers Conserv 12: 1391– Wilkinson IS & Priddel D (2011) Rodent eradication 1403. on Lord Howe Island: challenges posed by people, Recher HF & Clarke SS (1974) A biological survey livestock, and threatened endemics. In: Veitch CR, of Lord Howe Island with recommendations for the Clout MN & Towns DR (eds) Island invasives: eradi- conservation of the island’s wildlife. Biol Conserv 6: cation and management. pp 508–514. IUCN, Gland, 263–273. Switzerland. Sclater PJ (1869) Ocydromus sylvestris, sp. nov. Proc

175