Malherbe's parakeet

Malherbe's parakeet
At Isaac Peacock Springs wildlife refuge, New Zealand
Conservation status
Critically Endangered  (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Psittaciformes
Superfamily:	Psittacoidea
Family:	Psittaculidae
Subfamily:	Platycercinae
Tribe:	Platycercini
Genus:	Cyanoramphus
Species:	C. malherbi
Binomial name
Cyanoramphus malherbi Souancé, 1857[1]

The Malherbe's parakeet or orange-fronted parakeet (Cyanoramphus malherbi) is a small parrot endemic to New Zealand. In New Zealand it is commonly known as the Orange-fronted Parakeet, a name it shares with a species from Central America, while in the rest of the world it's known as Malherbe's parakeet.^[2]

The species name honours the French ornithologist Alfred Malherbe.^[3]

Taxonomy

The Cyanoramphus genus is endemic to the South West Pacific^[4] and it is suggested that an ancestor of Cyanoramphus dispersed from New Caledonia to New Zealand via Norfolk Island 500,000 years ago.^[5]

Controversy has surrounded the classification of this bird; is its own species or a colour morph of the similar Yellow-crowned Parakeet (C. auriceps)?^[4][5]

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 colour morph of the Yellow-crowned Parakeet.^[6] And as recently as 1990, the Ornithological Society of New Zealand considered it a colour morph of C. auriceps.^[4] The current consensus among researchers, which is also accepted by the New Zealand Department of Conservation, is that the Orange-fronted Parakeet is its own species.^[4][5] This was concluded with knowledge obtained through molecular genetic methods in 2000.^[7]

Description

The Orange-fronted Parakeet is a medium size parrot approximately 20 centimeters long. Its body is primarily a bright blue-green, with azure blue primary covert and leading edge feathers on its wings.^[8]

It has a distinctive (and diagnostic) orange frontal band on its yellow crown, but this is absent in juvenile birds which has a fully green head.^[2][8][9] The orange frontal band begins to develop when the bird is 2–5 weeks old.^[9] Its rump has orange patches on the sides.^[2][8]

The colouration in male individuals tends to brighter and juveniles are distinctively duller.^[8]

The only reliable colouration feature that separate mature orange-fronted parakeets from the similar yellow-crowned parakeet (C. auriceps) is the colour of the frons and rump.^[6][9]

Distribution and 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 island populations found on Maud Island, Blumine Island, Chalky Island, and Tuhua Island.^[2][8][10]

On the South Island, the parakeet is predominantly found only in Nothofagus/ Fuscospora (beech) forest^[2][8][11] with some reports of them being found in alpine and subalpine tussock and open matagouri shrubland.^[8][12]

On Maud Island, one study found that the parakeet prefers areas with greater canopy cover, and lower understory and ground cover.^[13] However the species is not restricted to this habitat and it is possible that as the density of the population increases usage of other habitat types could increase.

Behavior

The parakeet is most often observed foraging, preening, and resting.^[14] They show preference to the upper stratum of forests, but also frequent lower strata more often than C. auriceps.^[11]

Diet and Feeding

The Orange-fronted parakeet typically feeds in the canopy of beech trees, but will also forage in low vegetation and on the ground.^[8] They are typically observed feeding in flocks of mixed species, eating various seeds, beech flowers, buds and invertebrates.^[11]

During spring invertebrates become a significant part of their diet, including leaf roller larvae (Tortricidae spp.), aphids (Lepidoptera spp.), and leaf miners (Tineidae spp.).^[11]

They have been observed feeding on herbs and ferns on the ground, including Pratia spp., Oreomyrrhis colensoi, Parahebe lyallii, Leptinella maniototo and Blechnum penna-marina.^[11]

During mast years, beech seeds become the dominant feature of their diet.^[8][11]

The Maud Island population appears to have different preferences in its diet than mainland populations.^[15] Their diet consists of a greater number of plant species and invertebrates do not constitute such a large portion.

Breeding

The Orange-fronted parakeet is able to nest year round, but the peak breading period is between December and April.^[8] They primary nest in natural hollows or cavities of mature beech trees,^[2][8][13] preferring the red beech (Fuscospora fusca).^[8][11][13] On Maud Island they were found to nest in Pinus radiata forests.^[16]

Clutch sizes are around 7 eggs^[2][8][16] with an incubation period of 21–26 days.^[8][16] The female exclusively incubates the eggs and the male feeds her.^[2][16] Nestlings fledge between 43 and 71 days, but then remain dependent for 2–4 weeks.^[2][16]

Their breeding is also linked with the production of beech seed during mast years.^[2][8] During seeding events, and other periods where food is plentiful, the parrot is able to produce secondary clutches, with some pairs reportedly breeding up to four times in succession.^[8]

They are also monogamous.^[8]

Status

The Orange-fronted Parakeet was classified as Nationally Endangered by the New Zealand Department of Conservation in 2012^[17] and Critically Endangered by the IUCN.^[18]

In the 1800s the species was widespread occurring throughout New Zealand’s South Island. The birds were semi-nomadic; in that they would disperse in search of food when numbers were high.^[12] However this behaviour has stopped due to low numbers and habitat modification.^[8] This also has implications for re-establishment of the species.^[8]

Prior to 2000, the parrot’s population numbered in the hundreds on the South Island, but the population fell from 500-700 individuals to an estimated 100-200 by 2004 due to significant increases in rat and stoat populations.^[2] A rat plague during 2001 was a major contributor to this decline.^[19]

The Hawdon River valley houses the largest population of 70-200 individuals reported in 2013, but there is an apparent decrease in numbers.^[2] Additionally, the Poulter valley population also experienced a decline in numbers in 2013, with approximately 40-80 individuals occurring in this region. The South Branch Hurunui River valley population is even smaller with individual numbers as few as 20-40 birds.^[2]

The global population was estimated to be 290-690 individuals in 2013, with translocated island populations making up 160-420 of these birds.^[2] However, determining exact numbers of the parakeet is difficult due to their rarity, quiet nature, and similarities with C. auriceps.^[2][8]

Threats

The original declines in population sizes was most likely due to habitat destruction and dissection by early anthropogenic activity, hunting,^[20] and predation from exotic species.^[12][21] Hunting has ceased and their habitat protected, but habitat dissection may also continue to threaten the Orange-fronted Parakeet.^[20]

Currently, the declining numbers are primarily due to the introduction of exotic species; particularly the predatory stoats (Mustela ermine) and rats (Rattus spp.) which target eggs and nestlings.^{[2][8][13][20][21]} Given that the Orange-fronted Parakeet is an island species, it has evolved in isolation to significant predators; making it especially vulnerable to predation by introduced mammalian predators.^[20]

Deer and possums are also contributing to their decline through habitat modification.^[2][8] Possums also prey nestlings and eggs.^[8]

There also may be an increase in food supply competition.^[11][20] Introduced birds, mice, wasps, and rats are considerably reducing invertebrate numbers, which the parakeet relies on during winter and spring; therefore affecting their abundance.^[11] However, the parakeet is a food generalist and may compensate with other food sources, as observed on Maud Island.^[15] The flexibility of their diet is a promising characteristic for the recovery of the species.^[15]

Another prominent and inherent threat to the small populations of the parakeet is inbreeding depression and low genetic diversity; affecting the viability of populations by reducing their adaptive capacity to threats and diseases.^[20][22]

Furthermore, in beech silviculture the trees are not given enough time to develop adequate hollows before they are harvested, thereby reducing the number of suitable nesting sites in managed beech forests.^[2][13] Additionally, introduced Common Starlings may be outcompeting the parrot for nesting sites.^[8][23]

The specialised nesting habitat of the parakeet increases their vulnerability to extinction.^[16][21] The reasons for this include: (1) a single nest opening means that incubating females may be unable to escape from invading predators and will also be killed, (2) because only females incubate, predation may cause a biased sex ratio, (3) their relatively long nesting period (when compared to other passerines) increases their vulnerability to predation, and (4) the chicks tend to be noisy and therefore more attracting to predators.^[21]

Conservation

Given the primary cause of the current population declines, predator management is paramount.^[19][20]

All three mainland valley populations are subject to the Operation Ark initiative and are subject to multiple conservation strategies.^[2][19] Operation Ark is targeted at the control of stoat, possum and rat populations through integrated pest management,^[8][19] with particular focus on mitigating deleterious effects of predator plagues.^[19] Research has shown that pest management strategies have been successful in mitigating the impacts of predation by introduced mammalian predators.^[19][24]

Individual nest sites are also protected from predators using tin tree wraps,^[19] this has been a successful program and only one nest out of 153 has been lost to predators since 2003.^[2][8]

The other major conservation strategy is captive breeding programs carried out at Peacock Springs by the Isaac Wildlife Trust, with individuals being released on predator-free islands.^[2][8][19]

In 2005, translocations to Chalky Island began.^[19] A total of 45 birds were released between 2005 and 2007, and it was reported that the local population had increased to 150 individuals in 2009. By 2011 the population had increased to 100-200 individuals. However, this population declined to 50-150 individuals in 2013.^[2]

Between 2007 and 2009, translocations began on Maud Island where 68 individuals were released.^[2][10][19] However, in 2013 this population consisted of only 10-20 individuals.^[2]

Translocations have also occurred on Tahua Island and Blumine Island, with 2013 estimates of population size being 50-150 individuals and 50-100 individuals, respectively. These two populations, however, are not as well studied as those on Chalky Island and Maud Island.^[2]

References

External links

• Films of the Malherbe's Parakeet at IBC.org