Thinornis novaeseelandiae 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Charadriiformes Charadriidae

Scientific Name: Thinornis novaeseelandiae (Gmelin, 1789)
Common Name(s):
English Shore Plover, Shore Dotterel
Taxonomic Source(s): Turbott, E.G. 1990. Checklist of the Birds of New Zealand. Ornithological Society of New Zealand, Wellington.
Identification information: 20 cm. Stocky plover. Adult male, black forehead, sides of face, throat, collar. Brown in female. White ring above forehead, around back of head. Grey-brown crown, back of head, upper body. White underparts. Orange-red bill with black tip. Orange legs. Juvenile, white head, neck. Brown-grey cap, eye-patch. Brown bill with orange base. Voice Usual call kleet, adults call rapidly like oystercatchers when aggressive.

Assessment Information [top]

Red List Category & Criteria: Endangered D ver 3.1
Year Published: 2016
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Aikman, H., Askew, N., Dowding, J., Hitchmough, R., Miskelly, C., O'Connor, S. & Szabo, M.
Facilitator/Compiler(s): Benstead, P., Butchart, S., Harding, M., Khwaja, N., Mahood, S., McClellan, R., Taylor, J. & Stringer, C.
This species is classified as Endangered because it has an extremely small population. Translocated populations may not be sustainable. If habitat loss continues on its last island stronghold, and proves significant, it may require uplisting to Critically Endangered. However, recent data suggest that the population is now stable and additional sub-populations are becoming established.

Previously published Red List assessments:

Geographic Range [top]

Range Description:

Thinornis novaeseelandiae breeds on South East Island (Rangatira) (with vagrants to Pitt Island) in the Chatham Islands, New Zealand. A small population on Western Reef, Chatham Islands declined following its discovery in 1999, when 21 individuals were known (Bell and Bell 2000), and the last individual was taken into captivity in 2003 (Dowding et al. 2005). The species was once widespread around the coast of at least the South Island, but had been extirpated from mainland New Zealand by the 1870s. In 1937, the population on South East Island was estimated at 72 pairs by Fleming. Since grazing ceased in the 1960s, inland pasture used for nesting has become overgrown, and the population has declined and become increasingly restricted to the coast (Department of Conservation 2001). It has stabilised at 46-50 pairs and a post-breeding total in recent years of 115-150 adults (J.E. Dowding in litt. 2016). A population was re-established on Mangere Island, Chatham Islands by transfer of juveniles from South East Island between 2001 and 2003 (Dowding and O’Connor 2013). Suitable habitat is limiting on Mangere Island, and that population has stabilised at 7-8 pairs. Releases of captive-bred birds on islands off mainland New Zealand have had mixed success. On Motuora Island, Hauraki Gulf, two pairs bred but a population failed to establish and the two remaining males were re-captured for use in the captive-breeding programme (Dowding and O’Connor 2013). Translocations of juveniles to Waikawa/Portland Island from 1998 resulted in the establishment of a population that had reached 37 breeding pairs by 2011 (Dowding and O’Connor 2013)). A rat incursion in 2012 reduced this population to 4 pairs, and it is slowly being rebuilt, with 7 pairs breeding in 2015/16. In 2006, a single release was made at Release Site 4, an island off the South Island; further releases there were halted when birds were found to be carrying avian pox, and a population did not establish. In 2007, releases began on Mana Island, near Wellington. That population had reached 10 pairs by 2010/11, but an incursion by a single Norway rat in mid-2011 (Dowding and O’Connor 2013) eventually resulted in its extirpation (J.E. Dowding in litt. 2016). Further releases on Mana Island are planned. Releases have also occurred on Motutapu Island near Auckland since 2012, and 4 pairs were breeding there by 2015/16  (J.E. Dowding in litt. 2016).

Countries occurrence:
New Zealand
Additional data:
Estimated area of occupancy (AOO) - km2:5Continuing decline in area of occupancy (AOO):Unknown
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:29
Continuing decline in extent of occurrence (EOO):UnknownExtreme fluctuations in extent of occurrence (EOO):No
Number of Locations:4Continuing decline in number of locations:No
Extreme fluctuations in the number of locations:No
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:In 2015/16, the total wild breeding population numbered 65-70 pairs, with a post-breeding total of about 175 mature individuals in early 2016. About 70% of the breeding pairs were at a single location (South East Island), and this is the only population that can currently be considered relatively secure and self-sustaining in the long term. Numbers on South East and Mangere Islands are currently stable (both populations appear to be at carrying capacity), and recent fluctuations in the total population have been the result of the predator incursions on Mana and Portland Islands (Dowding and O’Connor 2013).

Trend Justification:  The species's population has stabilised and is now growing as reintroductions increase the number of breeding subpopulations on predator free islands.
Current Population Trend:Stable
Additional data:
Number of mature individuals:156-220Continuing decline of mature individuals:No
Extreme fluctuations:NoPopulation severely fragmented:Yes
No. of subpopulations:3Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No
No. of individuals in largest subpopulation:1-89

Habitat and Ecology [top]

Habitat and Ecology:On South East Island, it nests at the head of rock wave-platforms, and on salt meadow (J. E. Dowding in litt. 2008). While most birds on South East and Mangere Islands are confined to tidal rock platforms (there are no sandy beaches or estuaries), birds released on islands around the New Zealand mainland have used a wide range of habitat types, including sandy beaches, rocky shorelines, shingle beaches, and tidal estuaries (Dowding 2013, Dowding and O'Connor 2013). It feeds on small crustaceans, molluscs and other invertebrates, using the “run/step-stop-peck” technique typical of plovers, as well as "foot-trembling and beak probing" behaviour (Marchant and Higgins 1993, Armitage 2008). It lays two to three eggs in a nest set under dense vegetation, beach rack or boulders, usually on or near the shoreline (Davis 1994, Heather and Robertson 1997). On South East Island, where the population is at carrying capacity, breeding usually begins in the second or third year. Breeding has occurred in the first year at reintroduction sites and in captivity, where resources are less limiting (Dowding and O'Connor 2013). In 1986, the average age of the population was six years (Dowding and Kennedy 1993, Davis 1994). The oldest known individual was a male aged 21 years (J. E. Dowding in litt. 2008).

Systems:Terrestrial; Marine
Continuing decline in area, extent and/or quality of habitat:Unknown
Generation Length (years):6.7
Movement patterns:Not a Migrant

Threats [top]

Major Threat(s): Cats and brown rats Rattus norvegicus probably caused its extinction from the South Island (Dowding and Kennedy 1993, Davis 1994). The removal of sheep from South East Island in 1961 has resulted in loss of breeding habitat as previously grazed pasture has become overgrown. A small part of the marsh-turf near the south coast has also become overgrown; this process is likely to continue slowly but is not a serious concern. Other threats include fire, expansion of fur seal Arctocephalus forsteri colonies, disease, rough seas and storms, human disturbance and predation by Brown Skuas Catharacta antarctica (J. E. Dowding in litt. 1999, Department of Conservation 2001). Island visitors heighten these threats (Department of Conservation 2001). Losses from translocated populations have largely been the result of dispersal to the mainland (where they are killed by predators, although some birds have survived for several years before vanishing) and predation by native avian predators, including Morepork Ninox novaeseelandiae (Aikman 1999), Kelp Gull Larus dominicanus, and Swamp Harrier Circus approximans (Dowding and O’Connor 2013). Rat incursions on Waikawa/Portland and Mana Islands have demonstrated the extreme susceptibility of this species to introduced mammalian predators. The arrival of cats, rats, or mustelids (stoats, weasels or ferrets) is a constant threat requiring stringent biosecurity at all shore plover sites. These pests are common on mainland New Zealand. Outbreaks of avian pox in the captive population have caused mortality and delays in releases (Dowding and O’Connor 2013).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway

The recovery programme is overseen by the Department of Conservation’s Shore Plover Specialist Group. Birds are captive-bred at two institutions and the juveniles produced are released on suitable predator-free islands around mainland New Zealand. Just over 500 captive-bred birds had been released by mid-2016. The incursions on Waikawa/Portland and Mana Islands (both believed to be of a single Norway rat) have demonstrated the extreme susceptibility of shore plover to mammalian predators. Quarantine and surveillance measures are in place at all sites with shore plover to prevent the introduction of rats, cats, and mustelids. All populations are monitored at least twice annually. 
Conservation Actions Proposed
The recovery plan for the species has expired, and a new plan is in preparation. Diversity in the captive population is thought to be low, and genetic studies are under way to determine whether further eggs should be taken from South East Island to increase diversity in the birds released on islands around the mainland. Establishment of a third captive-breeding institution is under consideration. Trials of an avian pox vaccine are underway with the aim of reducing the impacts of that disease on the release programme.

Citation: BirdLife International. 2016. Thinornis novaeseelandiae. The IUCN Red List of Threatened Species 2016: e.T22693899A93429618. . Downloaded on 21 August 2018.
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