Justification of Red List Category
This species is classified as Near Threatened because it has a very small population which is estimated to approach the threshold for Vulnerable under criterion D1. The population is fragmented but no longer thought to be in continuing decline.
The population has been estimated at c. 1,900-2,000 birds (Heather and Robertson 1997, Sachtleben in prep.), thus the number of mature individuals is put at 1,200-1,400, based on the assumption that mature individuals account for around 2/3 of the total population.
The species appears to be stable or increasing in some parts of its range (Marchant and Higgins 1990, Sachtleben in prep.). In the Rotorua Lakes area (which holds one quarter to one third of the total population) the population increased by 57% from 364 individuals in 1985 to 572 individuals in 2011 (Sachtleben et al. 2014). The overall population was precautionarily suspected to be in decline owing primarily to habitat loss and modification and the impacts of human disturbance and introduced predators, however there is evidence to suggest that it may now be stable or even increasing (K. Owen in litt. 2012).
This species is endemic to New Zealand. The remaining population is restricted to North Island with a wide but fragmented distribution. Occasional vagrants have appeared in the north of South Island since the late 1980s. In 2012, a pair bred near Takaka, representing the first confirmed breeding record on South Island since 1941 (K. Owen in litt. 2012). The national population has been estimated to number 1,900-2,000 birds, including c.200 in Northland, c. 700 in the Volcanic Plateau, c.400 in the Hawkes Bay, c. 150 in Wairarapa and c.400 in Manawatu (Heather and Robertson 1997, Sachtleben in prep.). Numbers appear to be stable or increasing in some parts of its range (Marchant and Higgins 1990, Sachtleben in prep.), but the population is precautionarily suspected to be in decline overall, owing to continued threats. The reason for the rapid decline and extinction on South Island in the 19th century is not known.
It inhabits small bodies of freshwater such as sand-dune lakes and lagoons and larger inland lakes with shallow, sheltered inlets (Marchant and Higgins 1990, Heather and Robertson 1997). It also uses artificial habitats such as farm ponds and dams and oxidation ponds. It usually builds its nest on emergent vegetation at the water's edge, floating but attached to vegetation or overhanging branches; as such, it is easily broken up by wave motion or swamped (Marchant and Higgins 1990). It feeds predominantly on aquatic invertebrates, mostly insects and larvae, but sometimes fish and freshwater crayfish (Heather and Robertson 1997). Little is known about the species's life history or population dynamics.
Threats include the drying of dune lakes, destruction of nesting habitat, increasing vegetation, increased human activity on waterways, especially boat traffic, and predation by introduced rats Rattus spp. and mustelids Mustela spp., especially when nesting (Marchant and Higgins 1990, G. A. Taylor in litt. 1994, Sachtleben et al. 2014). The species is intolerant of disturbance by people on foot (Sachtleben et al. 2014). Nests are prone to boat wash caused by recreational boating, which occurs on many occupied lakes during the breeding season (K. Owen in litt. 2012). Low breeding success is achieved on large waters, possibly owing to fluctuating water-levels, wave action and disturbance by other species. Breeding success on dune lakes, farm dams and the sheltered arms of lakes appears to be higher (Marchant and Higgins 1990, K. Owen in litt. 2012), and increases in the number of water storage dams may be driving increases in this species's population in some areas (K. Owen in litt. 2012).
Conservation and Research Actions Underway
Infrequent, region-wide surveys have been undertaken to monitor some key population changes, e.g. the five-yearly census of the Rotorua lakes population (Sachtleben in prep.). Predator control operations since c.2002 have included the use of bait stations to control numbers of brown rats Rattus norvegicus around the shoreline of Lake Tarawera at the Tarawera settlement, which has led to a doubling of the local P. rufopectus population (Sachtleben et al. 2014).
Conservation and Research Actions Proposed
Regularly monitor population changes throughout its range. Carry out research into the species's life history and population dynamics (K. Owen in litt. 2012). Quantify the effects of introduced predators on breeding success. Consider reintroductions to the South Island (B. D. Bell in litt. 1999).
29 cm. Small, dark grebe. Blackish head with fine, silver feathers. Pale yellow eye. Dark, chestnut foreneck and breast. Black-brown upperparts. Paler non-breeding plumage. Similar spp. Hoary-headed Grebe P. poliocephalus is lighter and less red. Australian Little Grebe Tachybaptus novaehollandiae is smaller. Voice Silent except for chattering calls in breeding season.
Text account compilers
Benstead, P., Mahood, S., McClellan, R., Pilgrim, J., Taylor, J. & Ashpole, J
Bell, B., Owen, K., Robertson, H. & Taylor, G.A.
BirdLife International (2019) Species factsheet: Poliocephalus rufopectus. Downloaded from http://www.birdlife.org on 14/12/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 14/12/2019.