New Zealand has sometimes been described as a ‘land without teeth’.
Our native wildlife evolved to live in a land with very few land mammals (only two species of bat), so they were wholly unprepared for the onslaught of furry, four legged creatures that landed on our shores.
Eighty million years of isolation, meant our native animals took an evolutionary path that is utterly distinct.
Birds like takahe and kakapo grew fat and lost the ability to fly. Reptiles like the tuatara learned to ‘freeze’ as a response to predators, since the only predators at the time were avian. And many of our birds (like kea, falcon, and braided river birds) nested on the ground.
The introduction of mammalian pests and predators since people arrived in New Zealand has been the single most devastating problem for our native wildlife.
Early Maori bought kiore (Polynesian rats) and kuri (dogs), and by the time Europeans arrived two hundred years ago, kiore had already rendered tuatara extinct on the mainland.
In the last 200 years, a swag of predators have wreaked havoc on our remaining native wildlife. Our ‘dawn chorus’ was described by naturalist Joseph Banks on Captain Cook’s voyage around New Zealand as ‘deafening’. Now it has been reduced to a mere whisper.
New Zealand employs a range of measures to combat the onslaught of pests including trapping, shooting, ground-laying of poisons and the aerial and ground-based use of the biodegradable toxin, 1080 (sodium monofluoroacetate).
Forest & Bird supports the continued use of 1080 in New Zealand’s forests
as it is currently the most effective tool for significantly reducing pest numbers and
allowing native forests and wildlife to thrive.
We believe that using an aerial pest control method that –
- Readily breaks down in the environment
- Is particularly effective against introduced mammals (90% effective on possums, 98% on rats)
- Can be used over large areas of inaccessible rugged back country
Is a small price to pay for ensuring the survival of some of our most threatened species such as our endangered mohua, kaka, North Island kokako and powelliphanta snail.
Rata and pohutakawa
Severe possum damage to the pohutukawa forests on Rangitoto Island led to a dramatic decline in honey production in the 1980s. In the 1990s possums and wallabies were eradicated using 1080. New shoots on the pohutukawa tree trunks began appearing within weeks of the drop. However honey production only bounced back 10 years later when the trees fully recovered.
Likewise rata and fuschia are flourishing on the Otira valley in Arthur’s pass after 50 years of 1080 drops. Ten kilometres down the road on the Arahura valley where there’s no pest control, rata skeletons are abundant, and the forest is silent.
New Zealand’s unique giant Powelliphanta land snails have disappeared from most of our forests because of predation by rats and possums. After 1080 operations,
snail numbers increased threefold at sites in Kahurangi National Park, with large numbers of juveniles present. Pre 1080, there were 54 snails found on 500sq grid. One year after the 1080 drop, 147 snails were found on the same plot.
North Island Brown Kiwi
On average only 5% of North Island brown kiwi chicks survive to adulthood. Prior to a 1080 drop in Tongariro forest in 2001, 32 kiwi chicks were radio tagged. Post 1080, 40% of the radio-tagged chicks survived.
North Island kokako
The breeding population of kokako increased tenfold in Mapara Forest in the Waikato after four aerial 1080 operations in eight years. Effective control of possums, rats and stoats using 1080 is effectively saving this glorious songbird from extinction on mainland sanctuaries.
North Island Robin
Status: Least Concern
Nesting success of the North Island robin increased from 11% to 72% following aerial 1080 application in Pureora Forest. Robins are now being collected from Pureora to
re-populate other areas where pests have driven the birds to local extinction.
The valleys around North Canterbury - Hurunui, Hawdon and Eglinton – have all seen a decline in mohua numbers. All three populations declined in the 1990s, and were brought to new lows after a rat & stoat plague after the 1999 – 2000 season. After an aerial 1080 application though, the mohua population bounced back, despite declines in surrounding areas.
Karearea (NZ Falcon)
Status: Near Threatened
Falcon numbers at Kaiangaroa Forest increased from 20 to 36 pairs following aerial and ground 1080 control.
Status: Long tail - Vulnerable,
Short tailed – Critically Endangered
Bats were once abundant around New Zealand and could even be seen in Wellington, Christchurch, Dunedin and Invercargill . Now they live on a few forested scraps on the North and South Islands.
In a 2006 Fiordland study, long and short tailed bats were monitored in area of 1080 control, and in an area with no pest control. In the pest control area, the population remained steady. In the uncontrolled area, the bat population dropped by 20 – 30%.
Status: Nationally Threatened
Our kereru is one of the only NZ birds with beaks big enough to swallow our larger native berries – puriri, miro, karaka, nikau and kahikatea seeds. That makes them very important seed dispersers.
In the Wellington region, kererū counts increased from 29 to 142 at Kaitoke Regional Park following a number of aerial 1080 operations in the area. By helping to save our kereru though 1080, we’re also saving our forests