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Threats: The impact of introduced predators, principally stoats and rats, is likely to be the primary cause of decline, with recent population crashes being due to rat irruptions. The species's holenesting behaviour leads to a reduced ratio of females in the population due to predation of birds on the nest. Silviculture of beech forests aims to harvest trees at an age when few will be mature enough to develop suitable cavities, so sufficient nest holes are unlikely in managed beech forest. The species forages in low-growing shrubs and such lower forest levels have been subject to heavy browsing by cattle, deer and possums, altering the forest structure. Population growth in island populations, especially on Maud Island, may also be limited through predation by falcons (Falconidae), and displacement of two nesting pairs by introduced Common Starlings has now been documented; the overall impact of this recently-identified threat is uncertain, but may be minimal. In 2008, it was confirmed that native Red-crowned Parakeets C. novaezelandiae on Little Barrier Island were suffering from psittacine beak and feather disease (PBFD). The virus has been sequenced and appears very similar to the strain found in Crimson Rosella Platycercus elegans, in which the disease is known to be endemic within the captive population. In 2009, some individuals of C. malherbi on Maud Island were showing some symptoms consistent with PBFD. In reaction, testing of the entire captive population has been undertaken, as well as more limited sampling of individuals in all three island populations, as well as other parrot species. Results indicate that antibodies for PBFD were detected in C. malherbi from both Maud Island and the captive-rearing unit; notably in the latter case antibodies were found in the C. novaezelandiae foster parents and the disease has now been found in C. auriceps in the Eglington Valley, Fiordland. Monitoring for the disease in the captive population continues and it is hoped that the unit will soon be declared disease-free. C. malherbi at all three Mainland sites and on Tuhua were seen to be in very poor feather condition in 2012/2013, with a major infestation of Dermanyssus mites having occurred on Tuhua. On the mainland, mites were suspected but immunosuppression may also be involved, either because of small population size and/or because of post PBFD issues. Amount awarded:

$4,674

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Profile for Auckland Zoo

Auckland Zoo Field Conservation Report 2013/14  

Auckland Zoo field conservation report - 2013 / 2014

Auckland Zoo Field Conservation Report 2013/14  

Auckland Zoo field conservation report - 2013 / 2014

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