National Recovery Plan for the Norfolk Island Scarlet Robin (Petroica multicolor multicolor) and the Norfolk Island Golden Whistler (Pachycephala pectoralis xanthoprocta)
ObjectivesObjectives
Start here
Get a plain-English read of Objectives
Turn the raw legal text into a practical explanation grounded in National Recovery Plan for the Norfolk Island Scarlet Robin (Petroica multicolor multicolor) and the Norfolk Island Golden Whistler (Pachycephala pectoralis xanthoprocta).
The Norfolk Island Scarlet Robin Petroica multicolor multicolor (Robin) and Norfolk Island Golden Whistler Pachycephala pectoralis xanthoprocta (Whistler) are only found on Norfolk Island (29002’S, 167057’E). Although once found throughout the forests of Norfolk Island, and probably also on Phillip Island 6km to the south, each taxon is now restricted to a single population, in Norfolk Island National Park (465ha) and a few forest remnants mainly within 2km of the national park.
The total population sizes are currently estimated to be 440 breeding pairs of Robins and 535 breeding pairs of Whistlers. Total population sizes of both taxa are primarily limited by the small area of remaining suitable habitat, habitat fragmentation, habitat degradation and weed infestation, and introduced predators such as Feral Cats Felis catus and Black Rats Rattus rattus.
This Recovery Plan builds on earlier work to recover the Norfolk Island Green Parrot Cyanoramphus cookii and Norfolk Island Boobook Ninox novaeseelandiae undulata, and incorporates a multi-species approach wherever possible. It outlines actions which should change the conservation status of both the Robin and Whistler from 'Vulnerable' to 'Least Concern' within 20 years. This will be achieved by culling predators in forest remnants near Norfolk Island National Park (NINP), establishing and maintaining forested links to remnants, and if appropriate establishing second breeding populations on Phillip Island, which is free of mammalian predators. Population increases will also be achieved by extending the program to appropriate Public Reserves, providing habitat restoration incentives to private landholders, and involving the community in the recovery program.
Ultimately, the long-term goal should be to make Norfolk Island free of introduced mammalian predators (see Simberloff 2002). While this action is beyond the scope of this Recovery Plan, several studies cited in Veitch and Clout (2002) of Cat and Rat eradication from large islands, including those settled by humans, indicate that total eradication is a feasible target.
Biodiversity Benefits
The actions specified in this Recovery Plan will benefit a range of Norfolk Island threatened species. The existing control of Black Rats and Cats, which was initiated in 1992 mainly for Green Parrot conservation, greatly benefits other island fauna including Robins and Whistlers, a number of threatened plant species, the diverse land mollusk fauna and the two Vulnerable reptile species.
Habitat Critical to Survival
The most extensive area of native habitat remaining on Norfolk Island is within NINP, which encompasses 465 ha - 12% of the main island. Gilmour and Helman (1989) quantified the native vegetation assemblages of the Park at that time as 30% ‘native forest’ (palm, hardwood, and Norfolk Island Pine forest), 37% ‘weed-infested native forest’ and 33% ‘exotic forest’. Robins and Whistlers occur in all habitats within the national park and in some forested areas outside it (Robinson 1988, 1997, Major 1989, Bell 1990). The key elements of habitat critical for the survival of the Robin and Whistler are listed in Attachment 1 (habitat requirements), though the finer details of the Whistler's requirements are poorly known.
Habitat critical for the survival of both species includes all known sites for nesting, food resources, water, and shelter. This includes native and exotic forest and areas inside and outside NINP. Habitat with the potential to support Robins and Whistlers also fit the criteria of habitat critical for survival of the species, and the revegetated areas of Phillip Island may fall into this category, as well as potential habitat on Norfolk Island currently not used by Robins and Whistlers. Further work is needed to define these ‘potential’ areas and confirm their suitability. The known habitat critical for the survival of the Robin and Whistler is mapped in Figure 1 and is defined in this Recovery Plan as all potential Robin and Whistler habitat within their ‘current normal range’. This area is very similar to that determined for the Norfolk Island Green Parrot (Hill 2002). Most of the habitat of the Robin and Whistler is in national park, and public reserves, but some is on private land.
Image unavailable in extracted text
Threats
Predators
The Black Rat and Feral Cat continue to be the greatest threat to the island’s native vertebrate fauna (Commonwealth 2000). Baiting within the NINP has reduced numbers of the Black Rat (Innes 1995), and this, along with Cat control and the provision of more secure nest sites, has allowed Norfolk Island Green Parrot and Boobook numbers to increase (Olsen 1997, Hill 2002). Black Rats on Norfolk Island are probably the greatest potential risk to breeding seabirds, endemic reptiles, molluscs and any potential translocated birds, on Phillip Island (where there are currently not present).
While the Polynesian Rat Rattus exulans takes birds (McClelland 2002a, Pierce 2002), there has been a long period of co-existence, and it has been suggested that they are not a significant threat to landbirds (ANPWS 1984). Similarly, Norfolk Island Boobooks and Nankeen Kestrels Falco cenchroides may eat small numbers of Robins (Olsen 1997, Robinson 1997), and may take a few Whistlers, but their impact is likely to be small (Robinson 1997). Boobooks have co-existed with Norfolk Island landbirds for millennia, but Kestrels are recently self-introduced.
Habitat Loss, fragmentation and degradation
Native forest within NINP is protected under the EPBC Act, and a range of tree species are protected under Norfolk Island Government legislation. Weed-infestation and loss by natural attrition of mature habitat trees are degrading NINP and consequently, the habitat of Robins and Whistlers. On private land outside the national park, loss of native forest through clearing and by natural causes, and the subsequent expansion of dense weeds which crowd the understorey, is still a significant problem.
Robinson (1997) stated that the primary cause of declines in Robin and Whistler populations outside the NINP was probably past habitat loss and the subsequent fragmentation of the surviving populations into many small and isolated populations (Robinson 1988, Bennett 1990). Accordingly, if populations are to persist outside the park, the issues of habitat restoration and habitat isolation need to be addressed there. Some private landholders have already undertaken initiatives to maintain and extend native habitat for the threatened birds of Norfolk Island.
Vegetation management
Management actions may pose local threats to ground-foraging birds. For example, Robins avoid large bare areas recently cleared of weeds, and these areas may be reinvaded by densely growing weeds making them unsuitable for ground-feeding Robins in particular (Robinson 1997). Removal of grazing may also have a temporary detrimental effect, by reducing the openness of the understorey (Bell 1990). As noted by Mack and Lonsdale (2002), control or even eradication of a single invasive plant species may ultimately produce little benefit, if its demise only sparks the rise of another non-indigenous species.
Information gaps
The level of knowledge of the conservation requirements of the Robin (Robinson 1988, 1997, Major 1989) is sufficient to undertake management actions, such as habitat assessments for translocations, with confidence. On the other hand, there is a paucity of essential information on the Whistler (contra Garnett and Crowley 2000). This lack of detailed biological information will limit the reliability of proposed management actions.
New invasive species
The easiest, cheapest and often only the way to avoid significant impacts of invasives on an island ecosystem, is to prevent them getting to the island. To date, quarantine precautions have focused largely on rodents, but other organisms such as invertebrates, plants and even microorganisms can pose a greater, albeit less obvious, risk (McClelland 2002b).
Disease
Less immediate threats are the introduction of a new disease (Hay 1986), or one-off catastrophic events such as a cyclone (Robinson 1988). Island birds have often evolved in the absence of diseases common in continental bird faunas, and the introduction of such diseases can be disastrous. For example, psittacine circovirus disease was probably responsible for the deaths of many parrots on Norfolk Island in the mid-1970s (Hicks and Greenwood 1990). Similarly, the accidental introduction of avian malaria to Hawaii was probably the main cause of the extinction of several bird species (Hay 1986). Once established, a new disease may persist in feral populations of continental bird species which have resistance. For this reason, McNamara (1989) and Hill (2002) recommended that the eradication of introduced species from islands be given a high priority.
Competition
Competition with introduced birds (Common Blackbird Turdus merula and Song Thrush T. philomelos), and pesticides have been suggested as potential threats (Smithers and Disney 1969; Robinson 1988), although there is little evidence either factor had caused a decline in Robin populations or any other species of songbird (Robinson 1988).
Objectives
Overall Objective:
To shift the status of the Robin and Whistler from Vulnerable to Least Concern within 20 years.
Specific Objectives: to reduce the risk of extinction and improve conservation status of the taxa by:
Implementing threat abatement strategies;
Increasing the extent of occurrence of the taxa and their total population sizes;
Ensuring there is sufficient biological data to guide recovery program;
Increasing community involvement in and awareness of threatened landbirds;
Implementing the Recovery Plan through a Recovery Team.
Recovery Actions
Action 1. Predator control within NINP
Rat and cat control within NINP should incorporate the recommendations of Wilson (2002).
Action 2. Test effectiveness of and, if appropriate, expand predator control program outside NINP
Before conducting widespread control, the efficacy of this outside NINP must be demonstrated. Although isolated remnants of suitable habitat exist elsewhere, the birds have contracted mostly to the NINP in recent years. A trial of at least 10 remnants within 4km of NINP with and without pest control should be conducted, to determine control effectiveness. This will be combined with trail translocations, if necessary (see Action 6).
Action 3. Review quarantine protocols between Norfolk and Phillip Islands
Quarantine protocols between Norfolk and Phillip Islands require review, and updating if necessary. Phillip Island has the potential to be a major life-line for most threatened landbirds if it remains free of mammalian predators (Wilson 2002). Black Rats could be transported there by fishing boats and other craft. An island response plan for any new alien invasion has been suggested (Wilson 2002).
Action 4. Promote and support responsible Cat ownership
Continue sponsorship of cat de-sexing clinic. The Norfolk Island Government should be urged to enact legislation banning the import of reproductively-competent cats. An ultimate goal, beyond this Recovery Plan, should be to eliminate all reproductively-competent cats from Norfolk Island.
Action 5. Provide incentives and information for habitat restoration on private land
Investigate and promote incentives such as rate rebates for landholders who participate in habitat protection or predator control. Opportunities exist for the Natural Heritage Trust to protect remnant vegetation on private land. Management agreements between DEH and landholders, where DEH provides funding for fencing, have been put in place to protect and enhance native vegetation. These agreements are negotiated subject to availability of funds on a 3 yearly basis.
Action 6. Produce a translocation protocol and conduct local translocations if needed
If appropriate, translocation will be used to establish second breeding populations on Phillip Island. A translocation protocol (see Clarke and Clarke 1999, Clarke et al 2002) should be developed to cover all threatened NI birds. Although birds such as the Robin have recently declined outside NINP, the main island NINP territories are at carrying capacity (Robinson 1997), making this a potential donor site. In order to remove birds the Translocation Protocol may need to be included in the 'Research Strategy' or revised NINP Plan of Management (see Relationship to NINP Plan below). Following predator control trials (Action 2), trial translocations of birds to remnant sites may be needed if birds have not moved themselves following removal of predators. This will help determine whether isolation, predators, or a combination of factors are limiting bird distributions.
Action 7. Assess habitat suitability on Phillip Island and plan translocations
Currently about 95ha may be suitable and could support up to 60 pairs of Robins and 40 pairs of Whistlers. Forest suitable for Robins and Whistlers will displace current habitat suitable for some of the ground-nesting seabirds, though increased cover should not, for a considerable time at least, significantly limit seabird breeding habitat (Commonwealth 2000). If habitat surveys and local translocations prove positive translocations to Phillip Island can be planned and implemented. Implementing the translocations may be beyond the life of the current Recovery Plan.
Action 8. Collect habitat requirement and other biological data to guide recovery program
Habitat preference and other biological data on the Whistler and other insufficiently studied threatened species (e.g. Slender-billed White-eye), are needed to guide threat abatement, community awareness and translocations programs. These data can also be incorporated into existing forest restoration and management activities, and used to identify key areas for wildlife corridors and remnant protection (see Action 12). They will provide insights into adequacy of recruitment and replacement of rainforest and palm forest (key habitats) in NINP, and help guide forest restoration conducted by the Norfolk Island Parks and Forestry Service.
Action 9. Conduct multi-species monitoring of all threatened NI land bird species annually
Monitoring of all species annually (Robin, Whistler, Green Parrot, both White-eyes, and Boobook) will be more efficient and cost-effective then separate studies for each species. Monitoring protocols have been developed for Robins (Robinson 1997), Green Parrot (Hill 2002) and Boobook (Olsen 1997). Protocols for the Whistler and Slender-billed White-eye need refining.
Action 10. Promote public awareness and involvement
Public awareness activities should include a threatened bird brochure, and regular updates in the NI newspaper and other Norfolk Island media. The brochure should include all NI’s threatened birds, local names of birds, photos, decline maps, threat information, and how islanders can participate in recovery actions. A survey of community awareness and involvement would provide useful information for targeting future extension and management.
Action 11. Train and involve community in population monitoring and surveys
Public awareness (Action 10) will also encourage reporting of sightings, as this may be the only practical way to monitor some species outside NINP. Training in location and identification may be needed. In addition, a volunteer survey team should be formed to cover accessible habitat patches outside NINP, to provide data on patch sizes, habitat quality, and distances from source populations.
Action 12. Expand the Green Parrot Recovery Team to form a Norfolk Island threatened bird recovery team to manage recovery for all NI landbirds
Action 13. Commission an independent review of the recovery program after four years.
The NI Green Parrot Recovery Team should be expanded to include other external expertise and have its mandate extended to the conservation of all threatened NI birds. The team will endeavour to ensure funding for recovery actions, supervise the recovery program, meet publicity and reporting requirements, monitor performance of the plan, and commission an independent review.
Part Objectives - National Recovery Plan for the Norfolk Island Scarlet Robin (Petroica multicolor multicolor) and the Norfolk Island Golden Whistler (Pachycephala pectoralis xanthoprocta) - Objectives | Zoe