Data Zone
Justification of Red List category
The species is not believed to approach the thresholds for Vulnerable under the range size criterion (extent of occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend is increasing, and hence does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). Although the population size numbers less than 10,000 mature individuals, without a continuing decline it does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). The species is considered to be heavily dependent on conservation, but for the reasons above it is evaluated as Least Concern.
Population justification
The population was estimated at 2,130 individuals in the 2011 census (Dowding 2020), roughly equating to c.1,600 mature individuals (J.E. Dowding in litt. 2016). Numbers continue to increase, and assuming the same rate of increase as that between 2004 and 2011, the population was estimated to number 2,600 birds in 2020 (Dowding 2020), equating to c.1,900 mature individuals. In 2011, the east coast of the North Island held about 85% of the population, including nearly all managed subpopulations.
Trend justification
Overall the population is increasing, and this is predicted to continue (Robertson et al. 2021). Based on the results of four censuses across the period 1989-2011, the population increased by roughly 50% (from c.1,320 to 2,130 birds), and the overall rate of increase in the population between 2004 and 2011 was at least 16.7% (Dowding 2020), equivalent to c.30% over three generations. The eastern North Island population south of East Cape has more than doubled since 2011 (Robertson et al. 2021), and numbers recorded on the national water count have continued to increase (Riegen and Sagar 2020).
Charadrius aquilonius is endemic to New Zealand, where it breeds in the North Island. It occurs sparsely on the west coast from about Taharoa north to North Cape, with a few isolated pairs in Taranaki, but the bulk of the population is on the east coast between North Cape and East Cape (Dowding 2013). It has spread south of East Cape since 1990, but remains localised. In 2012, a pair bred at Riversdale in northern Wairarapa, the most southerly breeding record (Dowding 2013).
It usually breeds on wide ocean beaches (particularly at stream and river mouths), and around estuaries and harbours with tidal mudflats (Heather and Robertson 1997). It forms post-breeding flocks, usually at or near tidal estuaries (Dowding and Moore 2006). It also occurs in urban areas such as Auckland, where it sometimes breeds a short distance inland on short grass or bare earth (golf courses, verges, building sites, etc; Dowding and Moore 2006). It lays three eggs, and it feeds mostly on terrestrial and littoral invertebrates. Young generally begin to breed in their second year. The oldest recorded bird lived to at least 31 years of age (Heather and Robertson 2015).
Introduced predators remain the greatest threat - one study indicated that at unmanaged sites 60% of nests were lost to predators (Dowding 1998). The most important predators are cats, stoats Mustela erminea, and hedgehogs Erinaceus europaeus (Dowding 1998). Where native avian predators (notably Kelp Gull Larus dominicanus) occur at high densities, they are a significant threat to eggs and chicks. Coastal developments and encroachment by dune-stabilising weeds reduce habitat, and disturbance by humans, dogs, vehicles, and livestock reduces breeding success (Dowding 1993, Lord et al. 2001). Development and recreational use of the coast by humans is greater (and increasing) on the east coat, where most dotterels occur (Dowding and Davis 2007). Storms and very high tides can cause nest failures (Dowding 1998, Wills et al. 2003). Individuals have been lost to secondary poisoning during pest eradication operations (e.g. Dowding et al. 2006).
Conservation Actions Underway
Management at important breeding sites includes predator trapping, gull control, fencing of nesting areas, advocacy, reduction of nest losses to flooding, and the presence of wardens (Dowding and Davis 2007). This results in local improvements in breeding success. About 20% of c.600 breeding pairs were effectively managed in 1998-1999 (Dowding and Murphy 2001). This had risen to at least 30% of c.800 pairs by 2011, but with the loss in 2015 of sponsorship for the Coromandel programme, the proportion of the population under management will be much reduced (J.E. Dowding in litt. 2016). The New Zealand Dotterel Recovery Group disbanded in 2006. In some areas, there is substantial community involvement in management (e.g. Dowding 2006), and at some sites the species benefits from management of other species, notably New Zealand Fairy Tern Sternula nereis davisae. A revised species recovery plan was published in 2007 (Dowding and Davis 2007) but expired in 2014.
Conservation Actions Proposed
Complete a full census every seven years. Continue existing protection programmes, and expand protection to new sites, with priorities being on the west coast and in the Far North. Identify and protect important breeding, roosting and flocking habitat by advocacy and statutory protection. Seek sponsorship for management programmes, increase and support community involvement, and encourage other-agency partnerships, particularly with local government. The Department of Conservation’s recovery group no longer exists, and there is a clear need for national coordination and oversight of management programmes undertaken by other agencies and the community.
25 cm. Largest Charadrius plover. Sexes similar in eclipse. Brown upperparts. Feathers with paler edges. White forehead. Whitish underparts. Dark line through eye. Breeding adult, reddish underparts. Male, slightly redder on breast for much of year. Heavy black bill. Legs pale/mid grey. Iris dark brown. Voice Sharp chip most common call, long, loud churring call used in aggressive interactions.
Text account compilers
McClellan, R., Mahood, S., Taylor, J., Khwaja, N., Benstead, P., Harding, M., Symes, A., Vine, J., Stringer, C.
Contributors
Dowding, J.E., Hitchmough, R. & Parrish, R.
Recommended citation
BirdLife International (2024) Species factsheet: Northern Red-breasted Plover Charadrius aquilonius. Downloaded from
https://datazone.birdlife.org/species/factsheet/northern-red-breasted-plover-charadrius-aquilonius on 24/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 24/11/2024.