Parrocchetto di Malherbe

Identificazione

Malherbe's parakeet is a medium size parrot, approximately 20 centimetres long. Its body is primarily a bright blue-green, with azure blue primary covert and leading edge feathers on its wings.<p>It has a distinctive (and diagnostic) orange frontal band on its yellow crown, but this is absent in juvenile birds, which have fully green heads. The orange frontal band begins to develop when the bird is 2–5 weeks old. Its rump has orange patches on the sides. Colouration in males tends to be brighter, and juveniles are distinctly duller.<p>The only reliable features that separate mature orange-fronted parakeets from the similar yellow-crowned parakeet (C. auriceps) are the colour of the frontal band and rump.

Tassonomia

The genus Cyanoramphus is endemic to New Zealand and surrounding islands and it has been proposed that the ancestor of Cyanoramphus dispersed from New Caledonia to New Zealand via Norfolk Island 500,000 years ago.<p>Controversy has surrounded the classification of this bird; is it its own species or a colour morph of the similar yellow-crowned parakeet (C. auriceps)? It was described in 1857 from a museum specimen of unknown origin; its species name honours the French ornithologist Alfred Malherbe. During the late 1800s ornithologists considered it to be a distinct species, but during the latter half of the 20th century it was often considered a colour morph; as recently as 1990, the Ornithological Society of New Zealand listed it as a form of C. auriceps. After analysis using molecular genetic methods in 2000, the current consensus among researchers, which is accepted by the New Zealand Department of Conservation, is that Cyanoramphus malherbi is a distinct species.

Nome scientifico

Cyanoramphus malherbi

Autorità

Souancé, 1857

Ordine

Psittaciformi

Famiglia

Psittaculidae

Genere

Cyanoramphus

Areale e habitat

The species is found in only three regions on New Zealand's South Island: the South Branch Hurunui River valley, Hawdon River valley, and the Poulter valley. In addition, there are four translocated populations, found on Maud Island, Blumine Island, Chalky Island, and Mayor Island / Tuhua.<p>In the South Island, the parakeet is predominantly found only in Nothofagus/Fuscospora (beech) forest with some reports from alpine and subalpine tussock and open matagouri shrubland.<p>On Maud Island, one study found that the parakeet prefers areas with greater canopy cover and lower understory and ground cover. The species is not restricted to this type of forest, however, and as its population density increases it may make more use of other habitats.

Migrazione

Resident species

Comportamento

The parakeet is most often observed foraging, preening, and resting. They prefer the upper stratum of forests, but also frequent lower strata more often than C. auriceps.<p>The Malherbe's parakeet typically feeds in the canopy of New Zealand beech trees, but will also forage in low vegetation and on the ground. They are typically observed feeding in flocks of mixed species, eating various seeds, beech flowers, buds and invertebrates.<p>During spring, invertebrates become a significant part of their diet, including leaf roller moth and fungus moth caterpillars, other Lepidoptera, and aphids. They have been observed feeding on herbs and ferns on the ground, including Pratia, Oreomyrrhis colensoi, Parahebe lyallii, Leptinella maniototo and Blechnum penna-marina. During mast years, beech seeds become the dominant feature of their diet.<p>The Maud Island population appears to have different dietary preferences to mainland populations, eating more plant species and fewer invertebrates.<p>Malherbe's parakeets are monogamous and able to nest year round, but peak breeding is between December and April. They primarily nest in natural hollows or cavities of mature beech trees, preferring red beech (Fuscospora fusca). On Maud Island they were found to nest in Pinus radiata forests.<p>Clutch size is around 7 eggs with an incubation period of 21–26 days. The female exclusively incubates and the male feeds her. Nestlings fledge between 43 and 71 days, but remain dependent for 2–4 weeks.<p>Their breeding is also linked to the production of beech seed during mast years. During seeding events, and other periods where food is plentiful, they are able to produce secondary clutches, with some pairs reportedly breeding up to four times in succession.

Conservazione

Tendenza della popolazione

stable