Stoat in New Zealand

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A stoat in the Ardennes in Belgium, within its natural range Mustela.erminea.jpg
A stoat in the Ardennes in Belgium, within its natural range

The stoat (Mustela erminea) was introduced into New Zealand to control introduced rabbits and hares, but is now a major threat to the native bird population. The natural range of the stoat is limited to parts of the Northern Hemisphere. Immediately before human settlement, New Zealand did not have any land-based mammals apart from bats, but Polynesian and European settlers introduced a wide variety of animals. Rarely, in Southland, the fur of stoats has been reported to turn white, being the fur known as ermine, which adorns royal robes. [1]

Contents

self-resetting rat and stoat trap Self-resetting rat and stoat trap.jpg
self-resetting rat and stoat trap
Stoat emerging from a bird nesting box, near Raglan Stoat emerging from a bird nesting box.jpg
Stoat emerging from a bird nesting box, near Raglan

Introductions of stoats

The rabbit was introduced by European settlers as a food and game animal, and by the 1870s it was becoming a serious threat to the newly developed farming economy. Farmers began demanding the introduction of mustelids (including stoats) to control the rabbit plague. Warnings about the dangers to bird life from stoats were given by scientists in New Zealand and Britain, including the New Zealand ornithologist Walter Buller. The warnings were ignored and stoats began to be introduced from Britain in the 1880s. Within six years, drastic declines in bird populations were noticed. [2]

By 1930 the Auckland Acclimatisation Society was campaigning to end the protection of mustelids and cats. [3]

The translocation efforts of New Zealand's pioneering conservationist Richard Henry were undone when stoats swam to Resolution Island. Stoats were eradicated from Chalky Island and other Fiordland islands in the early 2000s, and scientists assumed that they would be unable to cross a 300 m water barrier, but stoats turned out to be able to reinvade: DNA testing confirmed that stoats regularly swim towards islands in summer, especially in beech mast years, and prefer long coastlines. [4] In December 2010, a stoat was seen on what was thought to be the stoat-free Kapiti Island, and by August the next year the New Zealand Department of Conservation had managed to remove three. It seems unlikely that a stoat could cross the five-kilometre stretch of open sea from the Kapiti Coast [5] but they are accomplished swimmers: in an experiment in a flume tank, a stoat paddled against a moderate current for two hours without stopping, the equivalent of swimming 1.8 km. [4]

Threat to bird life

New Zealand has a high proportion of ground-nesting and flightless birds, due to its long geographical isolation and a lack of mammal predators. Native birds have evolved to fill niches that are occupied by mammals in most other places. Stoats are the greatest threat to these ground-nesting and hole-nesting birds, which have very limited means of escaping stoat predation. In some areas the whio population is now 70% male, from stoats attacking female ducks incubating eggs. [4]

Stoat caught in a trap as part of a predator control initiative at the White Heron Sanctuary at the Waitangiroto Nature Reserve in Whataroa. Dion Arnold with a stoat.jpg
Stoat caught in a trap as part of a predator control initiative at the White Heron Sanctuary at the Waitangiroto Nature Reserve in Whataroa.

In addition to birds, stoats eat insects, mice and rats. During "beech masts", when southern beech trees ( Nothofagus species) produce a far greater amount of seed than normal, the stoat population undergoes changes in predation behaviour. With high beech-seed numbers, rats and mice become more plentiful, and the increase in prey encourages stoat breeding. The higher stoat numbers reduce the rodent population and the stoats then prey on birds. [6] For instance, the wild population of the endangered takahē dropped by a third between 2006 and 2007, after a stoat plague triggered by the 2005–2006 mast wiped out more than half the takahē in areas where stoat numbers were not limited by trapping. [7]

Control measures

A dead stoat retrieved from a trap in Fiordland Dead stoat, trapped in Fiordland National Park.jpg
A dead stoat retrieved from a trap in Fiordland

Stoats are difficult to control since they are bait-shy, trap-wary, and have high fecundity. [8] In some areas where there are populations of endangered birds, a programme of stoat-trapping has been implemented. The most common method of trapping is to use a stoat tunnel – a wooden box with a small entrance at one end to allow the stoat to enter. The bait is often an egg and a trap is placed in the tunnel to kill the stoat. [9] Recent trials of a new design of self-resetting stoat traps for remote areas have been encouraging. [10]

"Mainland Islands", protected areas on the mainland of New Zealand that employ intensive control of introduced pests, [11] have stoat trapping on their perimeter. Predator-proof fences, using fine wire-mesh netting, are used to keep stoats out of protected areas. Methods of restricting stoat breeding have also been investigated. [12]

In August 2022 a single male stoat managed to swim to Chalky Island, an important refuge and breeding ground of the critically endangered kākāpō parrot. Deeming it a major threat to the island's native wildlife, New Zealand's Department of Conservation (DOC) launched a massive operation to eradicate it, involving trapping experts, dogs, trail cameras, helicopters and boats. The operation cost around NZ$300.000 and took eight months until the stoat was finally trapped and killed. DOC defended the high cost, stating that the alternative would have been flying the kākāpō out of the island, with a cost amounting in millions. [13]

Legislation

Although stoats were recognised as a potential pest before being introduced into New Zealand, they were given protection as late as 1936. As a means of preventing a loss of biodiversity, there are now severe penalties for introducing stoats into protected areas. [14]

See also

Related Research Articles

<span class="mw-page-title-main">Stoat</span> Species of mammal

The stoat, also known as the Eurasian ermine or ermine, is a species of mustelid native to Eurasia and the northern regions of North America. Because of its wide circumpolar distribution, it is listed as Least Concern on the IUCN Red List. The name ermine is used especially in its pure white winter coat of the stoat or its fur. Ermine fur was used in the 15th century by Catholic monarchs, who sometimes used it as the mozzetta cape. It has long been used on the ceremonial robes of members of the United Kingdom House of Lords. It was also used in capes on images such as the Infant Jesus of Prague.

<span class="mw-page-title-main">Kākāpō</span> Large endangered flightless nocturnal parrot endemic to New Zealand

The kākāpō, sometimes known as the owl parrot or owl-faced parrot, is a species of large, nocturnal, ground-dwelling parrot of the superfamily Strigopoidea. It is endemic to New Zealand.

<span class="mw-page-title-main">Fiordland National Park</span> National park on South Island of New Zealand

Fiordland National Park is a national park in the south-west corner of South Island of New Zealand. It is the largest of the 13 national parks in New Zealand, with an area covering 12,607 km2 (4,868 sq mi), and a major part of the Te Wāhipounamu a UNESCO World Heritage Site established in 1990. The park is administered by the Department of Conservation. The southern ranges of the Southern Alps cover most of Fiordland National Park, combined with the deep glacier-carved valleys.

<span class="mw-page-title-main">Kapiti Island</span> Island off the Kāpiti Coast of New Zealand

Kapiti Island, sometimes written as Kāpiti Island, is an island nature reserve located 5.6 km (3 mi) off the west coast of the lower North Island of New Zealand and within the Kāpiti Coast District. Parts of the island were previously farmed, but it is now a predator-free sanctuary for endemic birds, including many endangered birds. The island is 10 km (6.2 mi) long, running southwest/northeast, and roughly 2 km (1.2 mi) wide, being more or less rectangular in shape, and has an area of 19.65 km2 (7.59 sq mi).

<span class="mw-page-title-main">Takahē</span> Species of bird

The South Island takahē is a flightless swamphen indigenous to New Zealand and the largest living member of the rail family. It is often known by the abbreviated name takahē, which it shares with the recently extinct North Island takahē. The two takahē species are also known as notornis.

<span class="mw-page-title-main">Resolution Island (New Zealand)</span> Island in New Zealands Fiordland region

Resolution Island or Tau Moana (Māori) is the largest island in the Fiordland region of southwest New Zealand, covering a total of 208 km2 (80 sq mi). It is the country's seventh largest island, and the second largest uninhabited island. Resolution Island is separated from the mainland of the South Island by Tamatea / Dusky Sound, Te Puaitaha / Breaksea Sound, and Acheron Passage. The island is part of the Fiordland National Park.

<i>Cyanoramphus malherbi</i> Species of New Zealand bird

Malherbe's parakeet is a small parrot endemic to New Zealand, where it is known as the orange-fronted parakeet or orange-fronted kākāriki. In the rest of the world it is called Malherbe's parakeet, as when it was recognised as a species, the name "orange-fronted parakeet" was already used for Eupsittula canicularis, a Central American species. Restricted to a few valleys in the South Island and four offshore islands, its population declined to around 200 in the 1990s, and it is considered critically endangered by the IUCN.

<span class="mw-page-title-main">Yellowhead (bird)</span> Species of New Zealand native bird

The yellowhead or mohua is a small insectivorous passerine bird endemic to the South Island of New Zealand. Once a common forest bird, its numbers declined drastically after the introduction of rats and stoats, and it is now near threatened.

<span class="mw-page-title-main">Secretary Island</span> Island in southwestern New Zealand

Secretary Island is an island in southwestern New Zealand, lying entirely within Fiordland National Park. Roughly triangular in shape, it lies between Doubtful Sound / Patea in the south and Te Awa-o-Tū / Thompson Sound in the north, with its west coast facing the Tasman Sea. To the east of the island, Pendulo Reach connects Te Awa-o-Tū / Thompson Sound with Doubtful Sound / Patea. Steeply sloped, the entirely bush-clad island rises to a chain of several peaks higher than 1000 metres. The highest of these is the 1,196-metre (3,924 ft) Mount Grono, the highest peak in the main New Zealand chain not located in the North or South Island. The island also contains three lakes. The largest, Secretary Lake, over 600 metres (2,000 ft) long, is located beneath Mount Grono at an altitude of 550 metres (1,800 ft).

Chalky Island or Te Kākahu-o-Tamatea is an island in the southwest of New Zealand, and is part of Fiordland National Park. It lies at the entrance to Taiari / Chalky Inlet, next to Rakituma / Preservation Inlet, at the southwestern tip of the South Island, 10 kilometres (6 mi) northwest of Puysegur Point, 15 kilometres (9 mi) southeast of West Cape, and 140 kilometres (87 mi) west of Invercargill. Chalky Island is one of the predator-free islands that is part of the Fiordland Islands restoration programme. The programme's focus is to eradicate pests and translocate native species.

<span class="mw-page-title-main">Anchor Island</span> Island of New Zealand

Anchor Island is an island in Dusky Sound in Fiordland.

Richard Treacy Henry was a New Zealand conservationist and reserve manager who became an expert on the natural history of flightless birds in New Zealand, especially the kākāpō. Born in County Kildare, Ireland, his family migrated to Australia in 1851 where he grew up. He moved to New Zealand in the 1870s, settling in the south-west at Lake Te Anau in 1883 where he worked as a handyman, rabbiter, shepherd, taxidermist, boat-builder, explorer and guide, while studying the birdlife. He also began to write articles on natural history for the Otago Witness and other publications.

<span class="mw-page-title-main">Pūkaha / Mount Bruce National Wildlife Centre</span> Captive breeding facility and visitor centre located in a protected nature area

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<span class="mw-page-title-main">Birds of New Zealand</span>

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<span class="mw-page-title-main">1080 usage in New Zealand</span> Pest control in New Zealand

1080, the brand name given to the synthetic form of sodium fluoroacetate, is used in New Zealand in efforts to control populations of possums, rats, stoat and rabbits, which are invasive species in the New Zealand environment. Although the Parliamentary Commissioner for the Environment deemed the use of 1080 in New Zealand "effective and safe" in a 2011 re-evaluation and the substance is widely considered to be the most effective tool currently available for controlling possums over large areas, it remains a contentious issue, with the majority of the debate occurring between conservationists and livestock farmers on one side and hunters and animal-rights activists on the other.

<span class="mw-page-title-main">Victoria Forest Park</span> Conservation park in New Zealand

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<span class="mw-page-title-main">Great Island (New Zealand)</span>

Great Island is an island in the southwest of New Zealand, and is part of Fiordland National Park. It lies in Taiari / Chalky Inlet, north of Chalky Island and contains two small lakes, Lake Dobson and Lake Esau.

<span class="mw-page-title-main">Murchison Mountains</span> Mountains in Fiordland National Park in New Zealand

The Murchison Mountains are a group of mountains in Fiordland National Park in New Zealand. It is the location where the South Island takahē, a type of bird presumed extinct, was rediscovered in 1948. The highest mountain is Mount Lyall at 1,892 metres (6,207 ft).

The Fiordland Islands restoration programme is run by the New Zealand Department of Conservation. The purpose of the programme is to eradicate pests on key islands around Fiordland National Park, once the islands are considered predator free endangered native species will be translocated to the islands.

<span class="mw-page-title-main">Sanctuary Mountain Maungatautari</span> Protected wildlife sanctuary in Waikato, New Zealand

Sanctuary Mountain Maungatautari, is a protected natural area in Waikato Region, New Zealand where the biodiversity of 3,400 ha of forest is being restored. The sanctuary covers the mountain peak, Maungatautari.

References

  1. ↑ Druett, Joan (1983). Exotic Intruders. Auckland: Heinemann. p. 171 – via New Zealand Electronic Text Collection.
  2. ↑ King, Carolyn (1984). Immigrant Killers. Auckland, NZ: Oxford University Press. ISBN   0-19-558121-0.
  3. ↑ "Waikato County: Monthly business: Stoats and weasels". Waikato Times. 10 December 1930. Retrieved 2020-04-16– via paperspast.natlib.govt.nz.
  4. 1 2 3 Hansford, Dave (July–August 2018). "The first test". New Zealand Geographic. 152: 74–91.
  5. ↑ Blundell, Kay (2011-08-27). "Stoat finds on Kapiti Island a threat to kiwi". The Dominion Post. Retrieved 2011-08-27.
  6. ↑ Purdey, D. C.; C. M. King; B Lawrence (2004). "Age structure, dispersion and diet of a population of stoats (Mustela erminea) in southern Fiordland during the decline phase of the beechmast cycle" (PDF). New Zealand Journal of Zoology. 31 (3). The Royal Society of New Zealand: 205–225. doi: 10.1080/03014223.2004.9518373 . Retrieved 2009-11-30.
  7. ↑ "Stoats decimating takahe in Fiordland". stuff.co.nz. 4 March 2008. Retrieved 23 April 2011.
  8. ↑ Taylor, Rowan (1997). "Chapter Nine: The State of Our Biodiversity". In Ian Smith (ed.). The State of New Zealand's Environment 1997. Wellington, NZ: Ministry for the Environment. ISBN   0-478-09000-5.[ permanent dead link ]
  9. ↑ "Stoats". New Zealand Department of Conservation. Archived from the original on 30 January 2016. Retrieved 2016-01-22.
  10. ↑ "Making Great Island great again". Department of Conservation. 22 March 2017. Retrieved 2017-10-16.
  11. ↑ "Mainland islands". New Zealand Department of Conservation. Retrieved 2016-01-22.
  12. ↑ "'Natural born killers' bred in New Zealand for the first time". Landcare Research. 2001-12-13. Archived from the original on 2012-04-18. Retrieved 2016-01-22.
  13. ↑ Tikekar, Dhruv (2024-04-10). "Why one country spent a small fortune to kill a single, elusive, furry predator". CNN. Retrieved 2024-10-28.
  14. ↑ Carter, Chris (2003-04-13). "New penalties for releasing pests in to sanctuaries". beehive.govt.nz. New Zealand Government. Retrieved 2016-01-22.
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