Working hard to preserve seabirds

A Kiwi at Cape Sanctuary. Photo / Paul Taylor

Paradise Saved
Dave Butler, Tony Lindsay and Janet Hunt
Random House, $55

A Kiwi at Cape Sanctuary. Photo / Paul Taylor

Hawke's Bay is fortunate to have a wildlife sanctuary right on its doorstep.

Cape Sanctuary at Cape Kidnappers is a thriving seabird sanctuary thanks to the care and attention of land-owners Andy and Liz Lowe, who own Ocean Beach Wilderness.

Paradise Saved is the remarkable story of New Zealand's wildlife sanctuaries and how they are stemming the tide of extinction.

Beautifully presented, the book tells of the incredible work of both scientists and volunteers to stop the decline of bird species.

If the human history of New Zealand entails a story of the retreat of seabirds from mainland nesting places to remoter offshore islands, then our gannet colonies are a delightful exception.

One of our greatest remaining colonies thrives at Cape Kidnappers in Hawke's Bay, where many visitors have enjoyed getting up close to these huge noisy birds - and their smell! However, today the cape is the site of an exciting new initiative that, among its initial achievements, is bringing back some of those other seabirds.

The vision for Cape Sanctuary came from land-owners Andy and Liz Lowe, who own Ocean Beach Wilderness. This vision now encompasses the Lowes' property along with areas of Cape Kidnappers Station, which is owned by Julian Robertson, and Haupouri Station, which is owned by the Hansen family.

An area of some 2200 hectares, stretching across the three properties, is now protected in a privately funded initiative supported by DoC and local iwi, and embraced by the wider community.

Technical advice is provided by one of New Zealand's leading ecologists and kiwi recovery experts, Dr John McLennan (see page 302), and Tamsin Ward-Smith manages the sanctuary with three other staff.

Rather like at Tawharanui and Shakespeare, the aim at Cape Sanctuary was to restore threatened ecosystems and species across a landscape with multiple uses, in this case farming, forestry and tourism. It was always recognised that the system would be 'leaky', with some pests able to get around the ends of the 9.5km, pest-proof fence at the points where there can be a 30-metre gap to the sea at low tide. The main road into the site was defended by only a cattle grid until 2013 when an automatic pest-proof gate was installed.

The pragmatic solution applied at the cape has involved several approaches: The peninsula-wide fence is a key element, dramatically reducing re-invasion; specific pests are also controlled to very low numbers in specific habitats; and a small 2ha, pest-proof fenced cell has been built to be kept pestfree, much like the enclosures at Sanctuary Mountain, though in the cape's coastal setting the re-introduction targets are burrow-nesting seabirds, reptiles and invertebrates.

The main fence was completed in 2007, and a comprehensive and ongoing pest-control programme begun inside it, using traps, poisons and shooting. The results mirror projects elsewhere. Possums are readily maintained at almost zero density - only two have been killed in the past six years - from a very low initial level due to the past work of Hawke's Bay Regional Council. The combination of best-practice trapping (more than 1400 traps) and secondary poisoning from baits set out for rodents (in 2200 bait stations) keeps stoats and ferrets at very low numbers. Rats, managed in key forest areas by poisoned baits and trapping, are about three-quarters of the number they are outside the sanctuary and declining further year by year. Mice have also been reduced at such sites.

However, the diverse landscape, with its large areas of grassland, led to one pest becoming a particular problem: the rabbit. Reductions in the populations of their predators actually led to rabbits reaching higher numbers inside the sanctuary than outside it. In 2013, the regional council, with co-funding from the land-owners, carried out an aerial poisoning programme that included much of the sanctuary, dropping carrot baits laced with either 1080 or pindone. Kill rates exceeded an amazing 99 per cent and by the end of 2014 it is hoped rabbits will be at low levels throughout the sanctuary.

That leaves feral cats as the most numerous carnivore in the sanctuary - 964 were trapped or shot between 2008 and 2013 - and the team are confident they will soon have these under control too. The fence may prove a key weapon - in reverse! - with cats climbing out to hunt the rabbits which are now in much higher numbers on the other side.

• As the fence went up and the pests were coming under control, a re-introduction programme began. It started in 2007 with the more widespread species: tomtits (still found in the site in small numbers), robins and whiteheads. If these did well, then that would be an indication that the pest control was sufficient and rarer species lost from the Hawke's Bay could be considered for reintroduction.

By 2013, 44 transferred robins had become more than 70 pairs, 26 tomtits had boosted their tiny population to more than 200 pairs, and 53 whiteheads numbered more than a hundred. In 2008, rifleman were added - only the second translocation of this species - and they have established a small core population in one area of eight to 12 pairs. This is clearly a great start.

Then came a debate about introducing two threatened species: the brown teal and the North Island brown kiwi. Was the site, with its dry summer conditions, relatively small areas of forest, and ongoing predator presence, too much of a risk? Rewind 10 years to the early days of DoC and approval would have been unlikely - at that time, DoC was tightening up the whole system of species translocation on the mainland, after years of ad hoc initiatives, many of which had failed. But by 2008, attitudes had changed as a result of almost a decade of successful releases across a wide range of species. There was now some appetite for trying a transfer even if success was uncertain, as a great deal could be learned from the process.

The sanctuary sees the arrivals of brown teal and North Island brown kiwi in 2008 as defining moments. Today, there are 150-200 teal, representing a significant 10 per cent increase in the global population, and more than 60 kiwi, a strong vindication of the original decisions - and much has indeed been learnt. The first kiwi were introduced as adults, or as juveniles of a weight (more than 800 grams) at which they were considered to be able to fend off stoats (see Chapter 8, page 301). Once monitoring showed the younger kiwi did just as well, the next step was to release small chicks a few weeks of age at the point at which they become independent. They, too, did well, which allowed Cape Sanctuary to then turn 'provider' as a kiwi creche or nursery, rearing chicks for other sites until they were large enough to be returned.

The owners' vision is to return to the sanctuary the full diversity of the region's past wildlife. Red-crowned parakeets, takahe and North Island saddlebacks have arrived in the past two years to add to the land birds present.

Coastal birds are mounting a comeback on their own. The rare New Zealand dotterel has moved into the sanctuary, and its breeding success there has significantly increased the regional population. Blue penguins, red-billed gulls and white-fronted terns are also now starting to thrive in the presence of fewer predators.

An active seabird re-introduction programme is also under way, making use of the fenced enclosure. It has been a massive undertaking, replicating the techniques described for Mana Island (see page 66). For five seasons, up to 76 grey-faced petrel chicks were introduced to artificial burrows and fed until they fledged, with about 90 per cent flying away. It's about seven years before this species returns as an adult to breed, so it's too early to judge success.

Similarly, almost 300 Cook's petrel chicks have been reared over four seasons, with almost all of them fledging - the first ones should return any time now. Finally, initial efforts with common diving petrels struck problems and a further attempt will be made in 2014.

In 2012 the seabird enclosure received Cape Sanctuary's most significant introductions to date: 60 tuatara 'gifted' from Ngati Koata to Ngati Mihiroa and passed to the sanctuary to look after. All that is needed now to create one of New Zealand's most special ecosystems is for the seabirds to return to nest. The seabirds' droppings, or guano, create a rich soil, which supports a particular flora and many invertebrates and lizards, which in turn are food for tuatara.

Cape Sanctuary illustrates what is possible when significant private resources are combined with strong science and support from the local community while the public cannot generally visit to see the wildlife unless they are volunteers or part of an organised group, they are reaping considerable benefits in other ways. Some of our rarer birds are now less threatened by extinction, and kiwi populations around the region are benefiting from a steady supply of recruits. Most significant may be the learning to come, as Cape Sanctuary tackles the ongoing challenges of keeping pests in low enough numbers to maintain the exciting gains achieved to date. New approaches are likely to be developed that will be applicable to many of the other sanctuaries in this book.

• To volunteer: For more information or to become involved as a volunteer, please contact the Cape Sanctuary manager. Email: capekidnappers@xtra.co.nz. Web: www.capesanctuary.co.nz.