The Rakiura Tïtï Restoration Project: Mitigation of the Command oil spill injury by eradication of rats from Sooty Shearwater breeding colonies in New Zealand

• Project Description
• Justification

• Objectives
• Study area
• Updates
• March 2005 - Trip to Titi Islands
• March 2006 - Blessing of the project
• July 2006 - Bait deployment
• Learn more about shearwaters
• contact
• Funding & Collaborators

Justification

Elimination of rat predation of eggs and chicks on Taukihepa, Pukeweka, Rerewhakaupoko and Mokonui islands is the most reliable and rapid method of replacing about 15,000 tïtï estimated to be lost because of the Command oil spill. Rat eradication was proposed for mid 2004 and occurred in July 2006 (see update). Computer simulations emphasize uncertainty in outcomes, but most likely scenarios predict complete recovery of the oil spill injury within a year after rat eradication. However simulations using extremely pessimistic assumptions predict that complete recovery may take four decades. Long-term benefits to tïtï and several other species and conservation of ecosystem processes will result.

Up to 15,000 adult Sooty Shearwaters may have been killed by the Command Oil spill in September 1998 during migration off the central California coast. The shearwaters (‘Tïtï’) are a treasured species of Mäori (New Zealand’s indigenous people) and a keystone species on over 40 Nature Reserves in New Zealand. The ‘kaitiaki’ (environmental guardians) of the tïtï request funding to repair the oil spill injury by eradicating rats from tïtï breeding colonies.

Sooty Shearwater (photo: Josh Adams)

Objectives

The four main objectives of the Rakiura Tïtï Restoration Project are to:

(i) eradicate the non-native introduced rats,

(ii) establish quarantine to prevent reintroduction of rats,

(iii) monitor and predict restoration success, and

(iv) create educational outreach to inform the people of New Zealand and California about the project.

Intensive study of the rate of loss of tïtï eggs and chicks to introduced rats, and comparisons of productivity before and after rat eradication, will allow computer simulation of rate of recovery of the Command oil spill injury post-eradication. Longer-term monitoring of tïtï abundance at fixed study plots 8 and 9 years after eradication will then check model predictions and allow more definitive prediction of ongoing restoration outcomes.

A large number of Rakiura Mäori visit the islands each year and they transport considerable quantities of food and gear from a variety of departure points. A concerted campaign to improve quarantine precautions will be instigated by this project. Rakiura Mäori scientists and managers will be employed to visit birders and urge care, to prepare posters and place poison bait stations at landing island sites. A video documentary about the restoration project will be used to heighten community awareness and quarantine efforts. The television documentary will be supplemented by CD-ROMS, interactive web-sites and a complete school educational package to educate Americans and New Zealanders about the project and need for environmental stewardship.

All methods for eradication, managing risks and monitoring outcomes have been proven and refined. Experienced and expert teams will secure funders investment in the restoration effort and make the operation safe. Recovery of the injury to tïtï is most likely to be rapid. Multiple long-term benefits to four island ecosystems and several non-target endemic species are certain additional outcomes.

International and Cross-cultural Collaboration

The Rakiura Tïtï Restoration Project promulgates a model for international and cross-cultural collaboration to mitigate the effects of a significant oil spill. Education effort will bring lasting benefits for conservation. The Rakiura Titi Restoration Project will build confidence that enlightened research, management and litigation can combine to restore environmental injury resulting from this negligence.

Sooty Shearwater breeding habitat (Photo: Melanie Massaro)

This photo shows the understory of a typical Tïtï breeding habitat (‘manu’). Thick well-developed peaty soil is pitted with breeding burrows under a tangled 3 – 7 m forest canopy. Tïtï lay an egg within burrows that can be up to 5 m long. Tïtï abundance, breeding success and productivity is determined by counting entrance holes and determining burrow occupancy using an infrared lit ‘burrowscope’ inserted down the burrows in search of eggs, chicks and breeding adults.

Map of Tïtï Islands - click on map to enlarge

Taukihepa (“Big South Cape”) is the largest (929 ha) of all the Tïtï Islands and the main target for restoration through rat eradication. It is fringed by steep cliffs and so in many places is accessible only by helicopter. This is ancestral land of scores of whänau (birding families) that continue their culture and livelihoods by a customary 6-10 week ‘heke hao kai tïtï’ (harvesting expedition). This customary practice and cultural identity is threatened by global pollution and catastrophes like the Command oil spill.

In the mid 1960s a rat plague on the islands saw the rapid extinction of several native bird species, the greater short-tailed bat and large insects. This wide-scale destruction was a very rude awakening for New Zealand - no one had suspected the enormous havoc introduced predators could wreak upon our ecosystems until that catastrope-Dr. Henrik Moller

(Photo: Darren Scott)

Updates

A visit to the Tïtï Islands, March 2005

Taukihepa Island, looking toward the South end of Rakiura (photo: H. Nevins)

Tïtï Islands are one of the world’s treasures of endemic flora and fauna. Because the birds provide a rich nutrient supply, to the islands, the resulting vegetation is stunning. The islands edges are fringed with a canopy of silvery green-gray Teteaweka (Olearia oporina), tree daisies under which the tïtï nest. On the larger islands, such as Taukihepa larger canopy trees such as Rata (Metrosideros umbellata) occur along the semi-protected hillsides, and provide a shaded understory comprised of a diverse assemblage of ferns, hebe, punui, and climbing vines of supplejack (Ripogonum scandens). However, on islands were ship rats (Ratttus rattus) or Kiore (R. exultans) are present, there is noticeable damage to the native plants. As a result, on islands with rats the understory vegetation is less diverse than on rat-free islands.

Kakariki (photo: Jamie Newman)

This gorgeous kakariki or Red-fronted Parakeet (Cynanoramphus novaezelandiae), currently occurs in lower abundance than prior to the 1964 rat irruption on Taukihepa (Big South Cape Island). Kakariki are cavity-nesting species and thus vulnerable to disturbance from rats, also competition for food must be important in limiting the abundance of this species on rat-infested islands. Thus the tïtï restoration project should benefit these birds.

Tieke or South Island Saddleback (photo: Jamie Newman)

The truly inspiring part of this conservation project is the potential for reestablishing the Tieke (Philesturnus carunculatus) on Taukihepa Island once rats are removed. Taukihepa Island was once the last strong hold for this species, which was only found here before the rat irruption and certain eminent extinction of this species was circumvented by conservationists who removed 36 individuals from Taukihepa and place them on nearby Kaimohu and Big Islands. Since 1986, Saddlebacks from this immigrant population have been translocated to several predator-free islands throughout the known historic range, including Breaksea and Ulva Islands.

Learn more about Tieke

Blessing of the project, March 2006

On March 20, A small gathering of birders, researchers, eradication specialists, and others involved in the project gathered together for a ceremony to bless the project at the high vantage point of Taukihepa where the surrounding islands could be addressed.

Maria sings a blessing song at the ceremony for the project
(photo: Hannah Nevins)

Large insects such as Weta and beetles were more abundant on Tïtï Islands. Once ship rats invaded Taukihepa, a large flightless weevil (Hadramphus stilbocarpuae) became locally extinct. Rodents depredate invertebrates and are especially devasting to flightless forms. Rat-free islands offer valueable refuges for these species.


Stag beetle (Geodorcus spp.) observed on rat-free Pohowaitai Island (photo: H. Nevins)

Bait Deployment! - July 2006

A specialized helo operator deploys bait over Taukihepa (photo: Pete McClelland)

On July 18, the Department of Conservation, working alongside local muttonbirders, successfully spread more than 7 tonnes of bait over the four rat-infested islands off the south-western corner of Stewart Island.

This bait drop was the first of two designed to eradicate all rats from Taukihepa (Big South Cape Island), Pukeweka, Rerewhakaupoko (Solomon) and nearby Mokonui (Big Moggy) islands to allow for the recovery of a range of endangered species and the restoration of the islands’ unique ecosystem (See press release).

Robert Coote, a birder and member of Ka Mate Nga Kiore says that all parties involved in the project have put in long hours of voluntary work to reverse a major past environmental catastrope.

It's not over yet however as we have just as great a challenge ahead gearing up to establish the quarantine procedure that will ensure the rats will never come back.
- Mr. Coote

Keep the Titi Islands pest-free!
Quaratine methods include taking extra care when you are:

• packing at home
• travelling by boat
• using helocopters
• unpacking at the islands
• travelling between islands

It is important for everyone to be vigilant - Inspect gear before departure to make sure no "stowaways" are on board. Store gear with bait stations. Unpack gear inside a closed room so that if one is there, it can be killed before escaping. Finally, notify a member of the island committee immediately when a rodent is detected on island.

Learn More...

Collaborators follow birds from California to New Zealand - Link to view maps

Learn more about the "Endless Summer" birds

Ocean Stewardship – Educational Materials

Interactive mapping by partner Signals of Spring

Papers

Moller, H.; Nevins, H. M,; Adams, J. 2003. The Rakiura Titi Restoration Project: Mitigation of the Command oil spill injury by eradication of rats from Sooty Shearwater breeding colonies in New Zealand. 78 pp. Unpublished Report for Rakiura Titi Islands Administering Body, January 2003

Funding & Collaborators

• Command Oil Spill Trustee Council
  Link to press releases:

• Ka Mate nga Kiore, Incorporated Society, Te Anau, NZ

• Rakiura Tïtï Islands Administering Body, NZ

• Southcoast Productions, Invercargill, NZ

• Kia Mau Te Tïtï Mo Ake Tönu Atu (“Keep the Tïtï Forever”) research team

• Dr. Henrik Moller, Zoology Department, University of Otago, New Zealand

• New Zealand Department of Conservation - Te Papa Atawhai
  
  Link to recent press releases about Titi Islands:
  
  Snipe take a step closer to mainland New Zealand, 18 April 2005
  
  Mutton birders report snipe breeding well on titi island, 11 June 2006
  
  First bait drop for four rat infested Muttonbird Islands, 18 July 2006

  
  

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  U.S. Contact