1 Taonga of an island nation: Saving New Zealand's birds May 2017 2 Acknowledgements The Parliamentary Commissioner for the Environment would like to express her gratitude to those who assisted with the research and preparation of this report, with special thanks to her staff who worked so tirelessly to bring it to completion. Photography Cover photo: © Rob Suisted / Nature's Pic Excluding photography, this document may be copied provided that the source is acknowledged. This report and other publications by the Parliamentary Commissioner for the Environment are available at: www.pce.parliament.nz Contents Contents 3 Overview / Tirohanga Whānui 5 1 Introduction 13 3 1.1 The purpose of this report 14 1.2 What comes next? 16 2 A brief history of New Zealand’s native birds 17 2.1 A land of distinctive birds 18 2.2 The arrival of humans 20 2.3 The growth of a conservation ethic 22 2.4 Recent developments 24 3 How safe are our birds? 27 3.1 Assigning threat rankings 28 3.2 Forest birds 30 3.3 Field, river, and coast birds 32 3.4 Sea birds 34 4 Not all species are alike 37 4.1 What is a species? 38 4.2 Which birds are most precious? 40 5 The big three predators 45 5.1 Possums, rats, and stoats 46 5.2 Dealing to the big three 48 5.3 Knocking down rat and stoat plagues during masts 50 5.4 Vital ongoing research 52 6 It’s not just possums, rats, and stoats 57 6.1 A range of predators 58 6.2 Mice, mustelids, and hedgehogs 59 6.3 Cats and dogs 60 6.4 Humans as ‘unintentional predators’ of seabirds 64 7 Breakthrough genetic science to deal with predators 67 7.1 Toxins that only kill particular predators 68 7.2 The Trojan female technique 69 7.3 Gene drive 70 4 8 Habitat – somewhere to live and thrive 71 8.1 Aspects of habitat that birds need 72 8.2 Animals that degrade bird habitat 74 8.3 Plants that invade bird habitat 76 8.4 Protecting and restoring habitat on private land 78 9 Bird genetics – resilience and restoration 85 9.1 The four forces of evolution 86 9.2 To mix or not to mix? 89 9.3 Inbreeding and genetic rescue 90 9.4 Moving birds to restore populations on the mainland 93 9.5 An urgent need for translocation policy based on clear principles 95 9.6 Being precautionary? Different attitudes to risk 96 10 Conclusions and recommendations 97 10.1 Predators – Starting a plan for Predator Free 2050 99 10.2 High priority research for predator control 101 10.3 Breakthrough methods for predator control using genetic science 103 10.4 Habitat – somewhere for birds to live and thrive 104 10.5 Bird genetics – inbreeding and restoration 106 10.6 Investing in our natural heritage 107 10.7 Supporting and coordinating community groups 109 Notes 111 References 122 Appendix 131 Overview This report begins with a vision – the restoration of abundant, resilient, and diverse birdlife on the New Zealand mainland. People who know me know that I am not generally given to visions. This one crept up on me during our investigation into 5 New Zealand’s native birds. Our birds are indeed a great treasure – they are a taonga of this island nation. The kiwi deserves its iconic status – it is one of the very few birds left in the world that is only a step away from the dinosaurs. But we also have parrots and penguins, gannets and gulls, shearwaters and shags, ducks and dotterels, and many others. There are 168 different species of native birds in New Zealand. Of these, 93 are especially precious because they are found in no other country. But they are far from safe. Only 20% – one in every five – is in good shape. And one in every three is not far off from following the moa and many others into extinction. The situation is desperate. Our native birds need three things – safety from predators, suitable habitat, and enough genetic diversity for long-term resilience. Undoubtedly, the first – safety from predators – is the most urgent. Possums, rats, stoats, and other introduced animals kill millions of birds every year. And it is not just birds – they also devour lizards and frogs and insects. Last year the Government announced the goal of making the country free of predators by 2050. While some might criticise this goal as unrealistic, it does something very important – it focuses our attention on the predators that are devastating our native fauna. In the future, breakthrough genetic technologies may make it possible to eradicate some predators altogether. But for the foreseeable future, the name of the game is predator suppression. Accordingly, I am greatly encouraged by the wave of innovation underway experimenting with new ways of luring, trapping, and poisoning predators. A range of creative ideas are on the table, and it is vital that this continues. It is also vital to recognise that aerial application of the toxin 1080 remains essential for the foreseeable future. An aerial 1080 drop will effectively (and cost-effectively) knock down populations of possums, rats, and stoats to low levels over large areas, even when these areas are rugged and difficult to access. It is also the only way we have of preventing the devastation of mast years, when rat and stoat numbers soar in response to an abundance of food. Possums, rats, and stoats are not the only predators. During this investigation, I have become increasingly concerned about the feral cats that now almost certainly number in the millions in the countryside and along forest margins. They are major killers of precious wading birds like the wrybill – the only bird in the world with a beak that curves to the side. Birds also need suitable habitat – somewhere to live. A population of birds might be safe from predators, but will not thrive without enough food and somewhere to nest. The honey-eaters – tūī and bellbirds – will not proliferate in a beech forest where wasps are eating all the honeydew. The habitat for New Zealand’s native birds is not just forest, and it is not all within national parks and other reserves. Restoring abundant, resilient and diverse 6 birdlife back on the mainland will involve bringing birds back to farmland, coasts, riverbeds, and cities. There is no shortage of interest. The QEII National Trust struggles to keep up with the demand for covenants that place permanent protection on areas of habitat on farmland. Similarly, Ngā Whenua Rāhui is engaged with placing kawenata on Māori land. And the number of eco-sanctuaries continues to grow, with many on private land. Finally, birds need a measure of genetic diversity. A great success of New Zealand conservation has been the eradication of predators on offshore islands, enabling them to be used as sanctuaries for birds. On the mainland also, some birds are effectively trapped in remnants of habitat. But small isolated bird populations can become inbred, and struggle to produce healthy chicks. On Tiritiri Matangi in the Hauraki Gulf, a kokako named Bandit is consorting with his grandmother. This may be a happy relationship, but it is unlikely to be a healthy one. We must guard against our birds drifting to the shallow end of the gene pool. In the last chapter of this report, I have made seven recommendations to Government Ministers. The first three recommendations are concerned with the most important and pressing thing birds need – safety from predators. The first recommendation is for the development of a plan for Predator Free 2050 – a living document that is revised and added to over time. All the disparate efforts currently underway will not just magically come together. There is a Far Side cartoon that captures this perfectly. It shows a group of cowboys and horses piled up in a heap outside the Sheriff’s office. The Sheriff is saying “And so you just threw everything together?... Mathews, a posse is something you have to organize”. The first element of such a plan needs to be the preparation of a portfolio of areas for sustained predator control. Like Taranaki Mounga, these areas need to be large, so they can support bigger populations of birds and reduce the risk of inbreeding, and slow the rate of predator reinvasion. The second recommendation highlights some areas of research that should be given a high priority. One of these is about optimising the effectiveness of 1080 drops. Another is about the urgent need to tackle the problem of feral cats effectively and humanely. In Australia, feral cats are widely recognised by the public as a great threat to their native species – we need the same cultural change to occur here. While the quest for scientific breakthroughs that could completely eradicate at least one predator is underway, we cannot afford to wait. We may eventually succeed in building a wonderful high tech hospital, but in the meantime the patient may die. We may succeed in developing a breakthrough genetic technique, but in the meantime, many of our bird species may disappear altogether. Recall that only 20% are in good shape. Doing better with current ways of controlling predators is critical. The third recommendation addresses the need for early engagement with the public over research into breakthrough genetic techniques. One of these techniques known as gene drive could potentially drive infertility through a population of 7 predators. Approaches like this that rely on genetic modification are likely to encounter strong opposition from some.