Document ID: chunk:federal_register_of_legislation:F2025L00287:reg:3:p147
Version: federal_register_of_legislation:F2025L00287
Segment Type: reg
Provision Reference: reg 3 (pt 147/276)
Character Range: 567520–570483

shown in Map 21.

Ecology
Breeding season is late September to March. The species can breed in the first year of life and produce two eggs per season. On average each pair produces one fledgling per year (Major 1989). Nests placed near the top of the subcanopy or in upright fork or horizontal branch of tree.
Feeds on invertebrates, mainly insects, foraging on the ground in deep litter where a dense understorey has an open ground layer (Robinson 1988) or using low horizontal branches from which to pounce on prey.
Map 21 Distribution of Petroica multicolor
The shaded area indicates the approximate current range of the Norfolk Island robin (Director of National Parks 2010, NIRC 2020.

Habitat
Mainly inhabits the cooler and damper native rainforest with lower densities in habitats dominated by Norfolk Island palm (Rhopalostylis baueri), African olive (Olea europaea cuspidata) or eucalypt plantations (Robinson 1988, 1997; Major 1989). The species generally prefers areas such as gullies with a deep moist litter layer, dense shrub layer 1–10 m tall to provide shelter and nests, and an open shaded layer near ground level to provide visibility for foraging (Robinson 1988, 1997).

Threats
The primary threat to survival of the population is predation from black rats. In a study in which nests were observed with remote cameras, rats preyed on 75% of nests and reduced nest success to 17%. In unbaited areas, rodent density was twice as high (8.1/ha cf 4.2/ha) and robin nest survival approximately 20 times lower (1.6% cf. 36.4%) than in baited areas (Dawlings and Clarke unpublished reported in Nance et al. 2021b). Population viability modelling suggests decline to extinction within six years in the absence of rat baiting (based on observed nest survival rates in unbaited areas; Nance et al. 2021b). Predation by cats and Argentine ants are also a threat. The invasive red guava (Psidium cattleyanum) is likely to increase rat populations by providing unlimited food supply for rats 3–4 months of the year (Nance et al. 2021b). A possible trend towards drier conditions in a changing climate (Bureau of Meteorology 2019) could affect the forest habitat of the Norfolk Island robin and the abundance of invertebrates they rely on for food (Nance et al. 2021b)

Impact on other species
None known.

Risk assessment
The risk assessment is shown in Table 53.
Table 53 Risk assessment for Petroica multicolor
Risk                                                                                    Likelihood of exposure    Consequence  Threat rating
1. Loss and fragmentation of native vegetation through past land clearing               Almost certain (91–100%)  Major        Extreme
2. Loss and fragmentation of native vegetation through current or future land clearing  Unlikely (11–25%)         Moderate     Low
3. Degradation of native vegetation through past grazing or loss of nutrients           Almost certain (91–100%)  Negligible   Negligible