Guest Editorial: What’s the Plan for Rakitū?

JOHN OGDEN

It seems to be the lot of the conservationist to go on and on repeating the same thing, backing it up with more and more evidence, and not being listened to. But it is particularly galling when the party not listening is also one you have supported with voluntary work for decades.

This is exactly the case with the issue of weka on Rakitū Island. The island is so well situated on the seabird super highway linking marine food resources and the remaining breeding colonies along the north-eastern coast of Aotearoa, that its restoration as a seabird ecosystem was a no-brainer. This, I was told, by Department of Conservation (DoC) staff, was the rationale for the rat eradication. Great, the GBI Environmental Trust knew the extensive published evidence – eradicating rats would allow re-colonisation by groundnesting seabirds.

The Trust has championed Rakitū for years, through Environmental News, letters to Ministers of Conservation and senior DoC staff, and attending innumerable meetings with DoC, iwi, and local board representatives. Trustees have been advocates for, and staunch supporters of, DoC. Support for the eradication of rats on Rakitū was maintained in the face of opposition and vilification by some members of the community.

North Island weka (Gallirallus australis greyi) is one of five distinct ‘subspecies’ recognised by the Weka Recovery Group (WRG) within DoC. Weka was regarded as one species (Gallirallus australis) until genetic profiling showed that some morphologically different populations were also genetically distinct. The population of this subspecies has declined and is subject to wide numerical fluctuations. The reasons for this are not known, but in the 1950s it was considered prudent to establish some island populations as an insurance against mainland extinction. In 1951, 15 weka were transferred from the Gisborne area to Rakitū. Since then – even in the presence of abundant rats – they have increased exponentially. At the time of the drop, there were an estimated 450 weka on Rakitū (although no actual count of weka appears to have been made). The WRG required that about 50 were to be removed, and subsequently returned. More than 50 weka were ‘easily captured’.

Removal was because it was thought that weka would be killed by eating rat bait, hence destroying the population of an endangered bird. The return was justified because no alternative location could be found for them, and Rakitū was considered by the WRG to be the best island on which to maintain a weka population.

The relative merits of weka versus seabirds, if discussed, must have been weighted by the convictions of the WRG. They were fully aware that the reason for the eradication campaign (as widely understood by the public) was restoration of Rakitū to a seabird nesting island, and that this result would not be achieved in the presence of weka. So, weka were returned to Rakitū, despite abundant literature, internal advice and external opinion, showing that they would prevent re-colonisation by seabirds.

Numerous accounts are available that document the impact of weka predation on seabirds. Fifty or even 450 weka may have relatively little effect on a colony of thousands of breeding birds. But that same number would have a devastating effect on a small colony (tens of birds) trying to re-establish on Rakitū after rat removal.

A ‘compromise’ suggestion of ‘fencing off’ bits of Rakitū to keep the weka from the seabirds is more appropriate for a zoo than for a wildlife island, and will again make DoC the laughingstock of Great Barrier. On the rugged coastal environment of Rakitū, fencing would probably be ineffective even in the short-term, visually unacceptable, and expensive,. Most importantly, it points to an unclear vision for island restoration.

With weka present, at best, some of the bigger species like grey-faced petrels may establish on cliff sites (which they do not prefer because burrows are hard to dig into rock!). Smaller species, such as storm petrels, prions, diving petrels, Cook’s petrel, fluttering and little sheawaters (all of which use the north-eastern super highway and nesting on nearby islands) do not stand a chance of returning to Rakitū in the face of predation by a population of several hundred breeding weka.

Part of the problem may be that many people, even within DoC, do not know what a ‘seabird island’ is like . Without firsthand knowledge it must be hard to have the vision. The nocturnal noise and bustle of thousands of ground nesting seabirds is an amazing experience, and speaks of an earlier Aotearoa.

Also, most people do not know how huge and diverse our former seabird populations were. There are more native seabirds than terrestrial species. Before human colonisation they were nesting everywhere on the mainland coast, even well up into the mountains – millions of birds digging in the soil, bringing huge amounts of phosphates and nitrates to land from the marine zone.

So far as I know, DoC has not published any rationale for the rat eradication. Despite verbal discussion locally, and three clear requests to the Minister of Conservation (2017, 2018, 2020), now, seven years since the eradication plan was funded, and three years since it commenced, there is still no management plan for Rakitū. There is still no published vision for a seabird island with iwi co-management and community involvement. Why?

Perhaps because the WRG are aware that leaving weka on Rakitū is a contentious issue on which they are likely to be in the minority; it is better not to have a plan. The strategy appears to be to keep public input to a minimum and run the island as a weka farm. If this is not the case – why has no management plan been published after so many years?

John Ogden is a former trustee of the Aotea Great Barrier Environmental Trust and is currently the Trust’s science advisor.