Justification
This species has a large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (extent of occurrence <20,000 km
2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population size may be moderately small, but with more than 1,000 individuals in the largest subpopulation it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). The population is suspected to be declining, but the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). For these reasons the species is evaluated as Least Concern.
Geographic Range Information
Megapodius layardi is endemic to
Vanuatu, being recorded from most islands north from Efate (Bregulla 1992). The species appears to be extinct on Tanna (Dutson 2011).
Population Information
The species is usually uncommon and localised but may be abundant close to communal nesting grounds (Dutson 2011). In 1995, it was surveyed on north-west Ambrym where 148 burrows (including 84 active or probably active burrows) were counted in three breeding grounds (Bowen 1996). In total, there are suspected to be more than 1,000 burrows on Ambrym (M. O'Brien in litt. 2021). Surveys in the Loru Protected Area on Espiritu Santo in 1995 recorded an average population density of 12 calling individuals per km2 (Bowen 1997), but birds appeared less common in other forests on the island (G. Dutson pers. obs. 1998). Surveys on Ambrym and Espiritu Santo in 2001 found the species to be widespread, but only locally common at few sites (Bowen 1997, O'Brien et al. 2003). On Tongoa, there is a colony of c. 300 burrows (M. O'Brien in litt. 2021).
The density and occurrence of the species on other islands in Vanuatu is less well known. While large colonies exist on Ambrym and Tongoa, the species appears to be more thinly spread elsewhere (M. O'Brien in litt. 2021). Surveys on Efate, Malakula, Gaua, and Vanua Lava in 2014 recorded the species only on Malakula (Andersen et al. 2017). Although there are no data from which to estimate a global population size, the population size could plausibly fall within the range 5,000-20,000 mature individuals (M. O'Brien in litt. 2021). With a minimum of 1,000 burrows suspected on Ambrym (M. O'Brien in litt. 2021), the largest subpopulation is thought to exceed 1,000 mature individuals.
Habitat and Ecology Information
It inhabits lowland hill forest, rarely logged forest, and has been recorded up to c. 800 m on Ambrym (O'Brien
et al. 2003, Dutson 2011). It is absent from other habitats except coastal vegetation adjacent to coastal nesting grounds (Dutson 2011). Singles, pairs and small groups forage on forest floor, sometimes alongside Red Junglefowl
Gallus gallus (Dutson 2011). It nests in volcanically heated areas, on beaches and in decomposing vegetation such as around rotting trees (Dekker
et al. 2000). As with other congeners, it is thought to be a dispersive species, flying to nesting and roosting sites, and not at risk from population fragmentation (Dekker
et al. 2000). It forages by scratching in the leaf-litter on the forest floor (Bregulla 1992, Bowen 1996).
Threats Information
Significant threats to the species include habitat loss and egg harvesting (Dutson 2011). Lowland forest across its range is subject to logging, local subsistence farming, slash-and-burn agriculture and cattle grazing (Dekker et al. 2000, S. Totterman in litt. 2007, Anderson et al. 2017), and remote sensing data indicate that forest loss is slow but ongoing (Global Forest Watch 2023, using data from Hansen et al. [2013] and methods disclosed therein). Coastal forests, where some communal nesting grounds are located, are particularly threatened (Dekker et al. 2000). The proportion of the total population that is harvested is unknown, but egg-collection is likely concentrated at the two biggest colonies on Ambrym and Tongoa (M. O'Brien in litt. 2021). During surveys on Malakula in 2014, researchers were shown two harvested eggs, so at least a small amount of egg collecting continues locally elsewhere (Andersen et al. 2017). While egg-collection has been restricted in some areas, bans are difficult to enforce and it is unknown whether populations are harvested sustainably (Foster 1999, R. Hills in litt. 2007, M. O'Brien in litt 2020). The species is also hunted by rural communities (Dekker et al. 2000).
The occurrence of non-native predators is a significant threat to the species, including cats Felis catus, dogs Canis familiaris and rats Rattus spp (Dekker et al. 2000, Anderson et al. 2017, M. O'Brien in litt. 2021). Cat predation has been recorded around the Ambrym colony and cats are likely to be significant predators of chicks (M. O'Brien in litt. 2021). In addition, feral pigs Sus scrofa cause degradation of understorey vegetation (Anderson et al. 2017).
Fires and cyclones degrade foraging and nesting grounds (Bregulla 1992, S. Maturin in litt. 1994, Bowen 1996, Foster 1999). The species is likely to be particularly sensitive to climate change, as a result of an increased frequency of cyclones, sea level rise, and increases in rainfall and temperature that could impact on breeding success (Radley et al. 2018).
Use and Trade Information
It is hunted by rural communities and egg-collecting is a significant threat (Dekker et al. 2000).
Conservation Actions Information
Conservation Actions UnderwayOn Santo the species breeds in the Big Bay and Loru protected areas and is legally protected from hunting between 1 July and 31 March (Dekker
et al. 2000). Egg-collection on Ambrym is restricted by a locally controlled system of taboos, which may have significantly reduced human disturbance (O'Brien
et al. 2003), although these bans are difficult to enforce and the proportion of the total population that is harvested sustainably is unknown overall (Foster 1999, R. Hills
in litt. 2007, M. O'Brien
in litt 2021)
. Wan Smol Bag Theatre and the Vanuatu Protected Areas Initiative have continued to raise awareness in support of taboos through community theatre, workshops and other initiatives.
Conservation Actions ProposedContinue to survey range islands to establish its distribution, status and threats. Assess the scale of egg-collection throughout the range. Monitor egg collection and investigate the effects of the existing taboo system on population numbers. Regularly review the effectiveness of existing conservation efforts on Ambrym. Study the impact of forest loss and degradation on the species' population density. Conduct ecological research focusing on productivity, dispersal and survival at nesting grounds. Monitor forest loss and degradation across the species' range. Encourage the adoption of sustainable harvesting regimes where appropriate. Enforce protected areas and taboos on egg collection. Continue education and awareness campaigns.