Aspects of the biology of managed populations of two Cyanoramphus parakeet species in New Zealand : breeding biology, pathogen screening and translocation : a thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Conservation Biology at Massey University, Auckland, New Zealand
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Date
2011
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Massey University
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Abstract
In this study, a visit to the remote Kermadec archipelago and the translocation of two
parakeet species to novel sites opened up opportunities to document aspects of the
biology of free-living and captive-bred parakeets. Four years after the eradication of
cats and rats on Raoul Island by the Department of Conservation, the Kermadec redfronted
parakeet has naturally recolonised this site, potentially from the adjacent
Herald Islets. Over a period of three weeks in March-April 2008, 100 parakeets were
captured on Raoul Island and the first evidence of nesting of the species at this site
since 1836 was recorded. These observations reinforce the view that eradication of
introduced predators such as cats and rats is a requisite for the recovery and
establishment of populations of New Zealand parakeets. These observations also
suggest that strategic eradication of cats and rats can facilitate the natural dispersal of
parakeets.
Taking into account the remarkable recolonisation of parakeets on Raoul Island and
the existence of islands free of introduced mammalian predators and red-fronted
parakeets in the Hauraki Gulf, a translocation of parakeets was envisaged. Between
April and May 2008, 32 red-fronted parakeets were translocated from Little Barrier
Island to Motuihe Island, in the first translocation of the species within the Hauraki
Gulf in 32 years. Alongside such transfer, a total of 62 captive-bred Malherbe’s
parakeets were monitored on Maud Island, in the Marlborough Sounds. Because the
translocations of red-fronted and Malherbe’s parakeets were temporally close, a
unique opportunity to study translocated free-living and captive-bred parakeets was
identified. The focus of monitoring on both sites was the detection of successful
nesting attempts, a short-term measure of translocation success. On both sites
(Motuihe and Maud Islands) evidence of successful nesting was found within a year
of the release of the first flocks.
As part of the planning steps for the translocation of red-fronted parakeets, a survey
was designed for four selected microorganisms of conservation concern for New
Zealand parrots: Campylobacter, Salmonella, Yersinia and the beak and feather
disease virus (BFDV). Only the latest was detected at a prevalence of 28% on Little
Barrier Island. Subsequent isolation and sequencing of BFDV genomes revealed a
previously undescribed genotype of this virus in New Zealand.
The discovery of a new BFDV genome in a wild population of endemic New Zealand
parakeets highlights need of future research. BFDV is known to affect the immune
system and survival of infected individuals in other species and is likely to hamper
conservation efforts for threatened parrot species. The challenges to study BFDV in
New Zealand, a global hotspot of parrot diversity, are outlined and high priority lines
of research are identified and discussed.
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Keywords
Kermadec Islands, Raoul Island, Red-fronted parakeet, Malherbe's parakeets, Motuihe Island, Maud Island, Rare birds, Wildlife relocation