The New Zealand Department of Conservation has introduced a number of animal and plant species to Mana Island, near Porirua, New Zealand, as part of an ecological restoration programme since taking over conservation management of the island in 1987. Some were reintroductions of species wiped out during years of agricultural use or the subsequent explosion in the number of house mice on the island. A pest control programme eliminated the mice by 1990 and many species have been introduced since. Notable successes include the spotted skink, Duvaucel's gecko and the flax weevil, which are now regarded as well established, and the yellow-crowned parakeet, which has been described as abundant and widespread. Attempts have been made to introduce several seabird species in what the Department of Conservation describes as "the world's most complex seabird translocation project"; results have been mixed.
Mana Island is a small (approx 217 ha, 0.84 sq mi) island off the southwest coast of the North Island, New Zealand. [1] : 5 Since 1987 the island has been owned and managed by New Zealand's Department of Conservation and is administered as a scientific reserve. [2] The island was previously used for agriculture, particularly the raising of sheep and cattle, and after grazing ceased, the growth of grass allowed a rapid increase of the house mouse population. [2] [3] The mice preyed on several native species of lizard and birds and damaged newly planted trees. [2] [4] An eradication programme successfully reduced the mouse population from 5 million in August 1989 to zero by February 1990. [2] The Department of Conservation carries out works to revegetate the island (which was probably originally forested) and restore it to an example of a Cook Strait island ecosystem. [1] : 9 [2]
The Friends of Mana Island volunteer group was formed in 1998 to carry out work at the island and to raise funds for its conservation. [3] A formal ecological restoration plan was established in 1999 and measures taken to reduce the growth of weeds such as boxthorn, boneseed, Senecio glastifolius and kikuyu grass. [1] : 5 A key aim is to introduce large colonies of seabirds, particularly burrowing types which have a significant positive benefit to local ecosystems through their actions in burrowing, gathering of nest materials and deposition of nutrients via droppings, regurgitations and corpses. They are able to support a large number of scavenger and predator species. The abandoned burrows can be used by wētā, skinks and tuatara. [1] : 9
There are plans to reintroduce all native animals that are known to have previously lived on the island, introduce other animals threatened on the North Island by invasive mammals and to introduce a wider variety of forest-dwelling invertebrates once the planted forest establishes a more mature leaf litter layer and is generating sufficient quantities of decaying wood. [1] : 29
The South Island takahē was introduced to Mana in 1987. [1] : 3 A male kiwi (a hybrid little spotted and Okarito) was released on Mana in October 1992. A female little spotted kiwi was released in June 1994. No successful breeding occurred and the female is thought to have died in 1998. The male was translocated to Allports Island in 2006. The Kiwi Recovery Group has recommended that Okarito kiwi be released on Mana in the future. [1] : 23
In 1995–96, 66 North Island robins were translocated to Mana from Kapiti Island. [1] : 3 : 26 They successfully bred and the population increased to 80 by 2010. Further increases are expected as the woodland matures into a more suitable habitat. [1] : 26 The brown teal was introduced in 2000–01, with 16 birds released. The population has successfully bred but remains small owing to the limited extent of wetland habitat on the island. [1] : 24 Yellow-crowned parakeets were introduced to Mana in 2004 from Te Kakaho Island. [1] : 25 They were breeding successfully by 2005 and were regarded as abundant and widespread by 2010. [1] : 5 : 25
An attempt was made to introduce rock wrens to Mana from Anchor Island in 2005, but this was unsuccessful. [1] : 25 Shore plovers were introduced in 2007 and started breeding on the island in the same year. [1] : 5 A count in 2010 showed 125 individuals on the island, of which 26 were permanently resident. There were six breeding pairs and seven fledged chicks. [1] : 25 In May 2010 approval was granted for the introduction of 40–60 whiteheads; this had been begun by 2018. [1] : 26 [3] New Zealand bellbirds had been spotted on the island in 1996, 2005 and 2008 but had not established there. [1] : 26 Approval was granted to release 40–60 individuals in May 2010 and this process had started by 2018. [1] : 26 [3]
Conservation authorities have suggested Mana as a possible site for introduction of Chatham Island snipe, despite the island being far from their natural range. [1] : 25 It has also been proposed that North Island fernbirds be introduced once the planted wetland areas have matured. [1] : 26
The Department of Conservation has stated that "Mana Island is the site of the world’s most complex seabird translocation project". [1] : 5 Birds are typically released as chicks and are handfed pureed sardine and krill by volunteers with syringes. [1] : 5 The common diving petrel was introduced from 1997 and 118 chicks fledged on the island over the next two years. [1] : 3 Of these some 20 chicks returned to breed. The population collapsed in 2010 from an unknown cause but subsequently recovered to around 20–25 breeding pairs. The Department of Conservation forecasts that numbers will continue to grow. [1] : 6 Fairy prion chicks were introduced in 2002 and 240 had fledged by 2004. [1] : 5 Some of these birds returned to breed in 2005, with a return rate of 8%. By 2008–09 only three breeding pairs were present on Mana and the colony was described as precarious. [1] : 6 Additional fairy prion chicks were translocated in 2015 and 2016. [3] Fluttering shearwater chicks were translocated to Mana in 2006 and 211 successfully fledged by 2008. [1] : 5
In 1997, a clifftop on the island's western coast was cleared to form a potential Australasian gannet habitat. The rocks were painted white to imitate guano and 100 concrete decoy birds were installed to attract passing gannets; since 1999 speakers have also played the birds' call. Some gannets briefly landed on the site in the late 1990s but did not stay. The area has since become overgrown. [1] : 8
A new site was cleared in March 2010 and the decoy measures installed there; the concrete decoys were regularly repainted by the Friends of Mana Island. [3] [1] : 8 In 2013 a single gannet, named Nigel by the conservation team, landed and settled on the island – the first gannet to do so in 40 years. Nigel seems to have regarded one of the concrete decoy birds as his mate, attempting to groom it, constructing a nest for them and attempting to mate. [5] [6] He was described in press reports as "the world's loneliest gannet". [6]
In December 2017, the decoys were repositioned and repainted in an attempt to improve their attractiveness; the speakers were also reorientated to point more out to sea. [6] Within ten days of this, three gannets landed on the island. [6] [5] Nigel paid them no attention, and died in his nest in late January 2018. [6]
In February 2019, 50 white-faced storm petrel were transported to Mana from the Chatham Islands and installed in artificial burrows. This species had been present on the island in pre-colonial times. [7] The chicks were hand reared by volunteers, who fed them with pureed sardines. [8] The Department of Conservation hopes to introduce a further 250 chicks before 2022. It is hoped that enough of the chicks will return to Mana after fledging and spending three to four years at sea to establish a viable colony. [7] It is estimated that a minimum of ten breeding pairs are required to start a sustainable colony. Previous translocation attempts with this species have seen return rates of 10–40%. [8] The Department of Conservation estimates that Mana is capable of sustaining a colony of 10 million breeding pairs; though as the members of this species only lay one egg a year it may take a century or more to increase significantly in number. [9]
Mana Island supported six species of reptile naturally and a further four have since been introduced. [1] : 5 In 1998, 50 spotted skinks were translocated from Matiu / Somes Island and 40 Duvaucel's geckos from North Brother Island and are now well established on Mana. Also in 1998 nine Wellington green geckos were released. A further 47 were released by 2005, drawn from captivity and wild populations between Pukerua Bay and Wainuiomata. These do not appear to have established on the island as there had been no confirmed sightings by 2010. In 2004, 48 speckled skink were relocated to Mana from Takapourewa, there have been few sightings but limited breeding was confirmed by 2010. [1] : 27 In 2015–2018, 49 ngahere geckos ( Mokopirirakau "southern North Island") were introduced. [10] [11]
Archaeological finds show that tuatara and the robust skink were previously present on Mana. [1] : 27 There are plans to introduce these and the Whitaker's skink to the island in the future. [1] : 28
The flax weevil was introduced to Mana Island in 2004; a further 80 were translocated from Maud Island in May 2006 and 70 in June 2006. The release site was at the south of the island, near to the petrel colony. The weevil had become well established on the flax plants on the island by 2010. A number of Hutton's speargrass weevils, sourced from the southern Wellington Region coast, have been released on the western cliffs of Mana Island. Seven were released in March 2006 and nine in December 2007. A 2010 study found evidence of feeding but numbers had not significantly increased. [1] : 29
It has been proposed that the New Zealand reticulate stag beetle, the giant pill millipede and the land snails Rhytida greenwoodi , Wainuia urnula and Powelliphanta traversi otakia be released once the woodland on the island has matured sufficiently to provide the necessary deep leaf litter layer, decaying timber and established tree ferns. A wider selection of forest-dwelling invertebrates from Kapiti Island may also be introduced once a canopy of kohekohe, milk tree and tawa has formed. [1] : 29
As part of the revegetation plan the Department of Conservation has introduced 22 plant species to the island. [1] : 5 : 9 These include selected native New Zealand species, particularly those under threat elsewhere. [2] Since 1987 more than 500,000 trees have been planted on the island. [3]
The island's wetland area is small and not yet well established. The area may be suited to the introduction of brown mudfish. No link to the sea has been proven which would be required for the introduction of any diadromous fish species. [1] : 28
Seabirds are birds that are adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations. The first seabirds evolved in the Cretaceous period, and modern seabird families emerged in the Paleogene.
The family Procellariidae is a group of seabirds that comprises the fulmarine petrels, the gadfly petrels, the diving petrels, the prions, and the shearwaters. This family is part of the bird order Procellariiformes, which also includes the albatrosses and the storm petrels.
Zino's petrel or the freira, is a species of small seabird in the gadfly petrel genus, endemic to the island of Madeira. This long-winged petrel has a grey back and wings, with a dark "W" marking across the wings, and a grey upper tail. The undersides of the wings are blackish apart from a triangle of white at the front edge near the body, and the belly is white with grey flanks. It is very similar in appearance to the slightly larger Fea's petrel, and separating these two Macaronesian species at sea is very challenging. It was formerly considered to be a subspecies of the soft-plumaged petrel, P. mollis, but they are not closely related, and Zino's was raised to the status of a species because of differences in morphology, calls, breeding behaviour and mitochondrial DNA. It is Europe's most endangered seabird, with breeding areas restricted to a few ledges high in the central mountains of Madeira.
The magenta petrel, or Chatham Island tāiko, is a small seabird in the gadfly petrel genus, Pterodroma. Found exclusively on Chatham Island, New Zealand it is one of the rarest birds in the world, believed to be extinct for over 100 years before its rediscovery in the 1970s.
Matiu / Somes Island is the largest of three islands in the northern half of Wellington Harbour, New Zealand. It is the former site of military and quarantine internments, as well as animal quarantine until 1995. Since 1995 it has been designated a Department of Conservation historic and scientific reserve, home to many native species.
The Australasian gannet, also known as the Australian gannet or tākapu, is a large seabird of the booby and gannet family, Sulidae. Adults are mostly white, with black flight feathers at the wingtips and lining the trailing edge of the wing. The central tail feathers are also black. The head is tinged buff-yellow, with a pale blue-grey bill edged in black, and blue-rimmed eyes. Young birds have mottled plumage in their first year, dark above and light below. The head is an intermediate mottled grey, with a dark bill. The birds gradually acquire more white in subsequent seasons until they reach maturity after five years.
The Chatham albatross, also known as the Chatham mollymawk or Chatham Island mollymawk, is a medium-sized black-and-white albatross which breeds only on The Pyramid, a large rock stack in the Chatham Islands, New Zealand. It is sometimes treated as a subspecies of the shy albatross Thalassarche cauta. It is the smallest of the shy albatross group.
Mana Island is the smaller of two islands that lie off the southwest coast of the North Island of New Zealand. The name of the Island is an abbreviation of the Maori name Te Mana o Kupe, which means "The Mana of Kupe".
The Westland petrel(Procellaria westlandica),, also known as the Westland black petrel, is a moderately large seabird in the petrel family Procellariidae, that is endemic to New Zealand. Described by Robert Falla in 1946, it is a stocky bird weighing approximately 1,100 grams (39 oz), and is one of the largest of the burrowing petrels. It is a dark blackish-brown colour with black legs and feet. It has a pale yellow bill with a dark tip.
The Bermuda petrel is a gadfly petrel. Commonly known in Bermuda as the cahow, a name derived from its eerie cries, this nocturnal ground-nesting seabird is the national bird of Bermuda and can be found pictured on Bermudian currency. It is the second rarest seabird on the planet and a symbol of hope for nature conservation. They are known for their medium-sized body and long wings. The Bermuda petrel has a greyish-black crown and collar, dark grey upper-wings and tail, white upper-tail coverts and white under-wings edged with black, and the underparts are completely white.
Albatrosses, of the biological family Diomedeidae, are large seabirds related to the procellariids, storm petrels, and diving petrels in the order Procellariiformes. They range widely in the Southern Ocean and the North Pacific. They are absent from the North Atlantic, although fossil remains show they once occurred there and occasional vagrants are found. Albatrosses are among the largest of flying birds, and species of the genus Diomedea have the longest wingspans of any extant birds, reaching up to 3.7 m (12 ft). The albatrosses are usually regarded as falling into four genera, but disagreement exists over the number of species.
The Wellington green gecko is a species of gecko found only in the southern half of the North Island of New Zealand. It was previously considered a subspecies of the Auckland green gecko, and together called the common green gecko.
The black petrel, also called the Parkinson's petrel, is a medium-sized, black-plumaged petrel, the smallest of the Procellaria. The species is an endemic breeder of New Zealand, breeding only on Great Barrier Island and Little Barrier Island, off the North Island. At sea it disperses as far as Australia and Ecuador.
The white-bellied storm petrel is a species of seabird in the family Oceanitidae. It is found in Angola, Argentina, Australia, Brazil, Chile, Ecuador, French Polynesia, French Southern Territories, Maldives, Namibia, New Zealand, Perú, Saint Helena, and South Africa. Its natural habitat is open seas.
Gould's petrel is a species of seabird in the family Procellariidae. The common name commemorates the English ornithologist and bird artist John Gould (1804-1881).
Hutton's shearwater or the kaikōura tītī, is a medium-sized ocean-going seabird in the family Procellariidae. Its range is Australian and New Zealand waters, but it breeds only in mainland New Zealand. Its conservation status is Endangered, because there are just two remaining breeding colonies, located in the Seaward Kaikōura Range. Six other shearwater colonies have been wiped out by introduced pigs. Hutton's shearwater is the only seabird in the world that is known to breed in alpine areas. Conservation measures for the bird include community initiatives to rescue birds that crash-land at night on streets in Kaikōura, and the establishment of a protected area on the Kaikōura Peninsula including a predator-proof fence, man-made burrows, and translocating fledglings from the remaining colonies.
The Noises are a collection of islands lying northeast of Rakino Island in Auckland's Hauraki Gulf, off the coast of the North Island of New Zealand. The largest and most forested islands are Ōtata and Motuhoropapa; Orarapa and Maria/Ruapuke are also significant. After a rat eradication campaign in the 1960s, Maria was the first New Zealand island to become predator-free. The lack of invasive predators, intact native forest, and large numbers of breeding seabirds give the Noises significant conservation value. There has however been a marked decline in marine biodiversity surrounding the islands from over-fishing.
Motu Matakohe, also known as Matakohe or Limestone Island, is a 37 ha island in the upper reaches of Whangarei Harbour, just off Onerahi, a seaside suburb of the city of Whangarei, Northland, New Zealand. Used for farming and industry for many years, the island is an example of ecological island restoration by a volunteer community group.
Seabirds include some of the most threatened taxa anywhere in the world. For example, of extant albatross species, 82% are listed as threatened, endangered, or critically endangered by the International Union for Conservation of Nature. The two leading threats to seabirds are accidental bycatch by commercial fishing operations and introduced mammals on their breeding islands. Mammals are typically brought to remote islands by humans either accidentally as stowaways on ships, or deliberately for hunting, ranching, or biological control of previously introduced species. Introduced mammals have a multitude of negative effects on seabirds including direct and indirect effects. Direct effects include predation and disruption of breeding activities, and indirect effects include habitat transformation due to overgrazing and major shifts in nutrient cycling due to a halting of nutrient subsidies from seabird excrement. There are other invasive species on islands that wreak havoc on native bird populations, but mammals are by far the most commonly introduced species to islands and the most detrimental to breeding seabirds. Despite efforts to remove introduced mammals from these remote islands, invasive mammals are still present on roughly 80% of islands worldwide.
Motuora is an 80 ha island nature reserve in the western Hauraki Gulf, on the north-eastern coast of New Zealand's North Island. It lies some 6.2 km (3.9 mi) south-west of Kawau Island, 5 km (3.1 mi) east of Mahurangi Heads and 35 kilometres (22 mi) north of the city of Auckland.