Bethany Jackson

Introduced mammalian predators and anthropogenic habitat modification have resulted in the loss of 62 avian species since humans arrived in New Zealand. The conservation paradigm for New Zealand relies upon predator free, ecologically intact or restored islands to serve as sanctuaries and breeding sites for a range of threatened species. Island breeding programs and translocations to restore native fauna to the mainland and other off-shore sites, introduce specific risks related to disease spread. Beak and Feather Disease Vims (BFDV), was found in clinically affected juvenile Red Crowned Parakeet (RCP, Cyanoramphus novaezelandiae) on Hautum Island in 2008. This finding had major implications for conservation management of parrots in New Zealand, including the critically endangered kakapo (Strigops habroptilus) and orange fronted parakeet (Cyanoramphus malherbi). Feather loss had also been reported in RCP on nearby Tiritiri Matangi Island, suspected to be caused by BFDV. BFDV is endemic in the exotic Eastern rosella (Platycercus eximius) and Sulphur-crested cockatoo (Cacatua galerita) on the North Island of New Zealand. A spill over event likely spread the vims to RCP on nearby islands in the Hauraki Gulf of the Auckland region. Four cross-sectional surveys were conducted between 201 1-2012 on Tiritiri Matangi Island to determine the presence, prevalence and seasonal trends of key diseases of parrots that may result in feather loss. A total of 184 birds were captured in mist nets. All birds were anaesthetised to collect samples of blood, feathers and faeces, and in 2012 a skin biopsy from the head was included. Individuals were examined for general condition including stages of moult and body weight, and morphometrics and standardised photos were obtained. Hippoboscid flies were collected opportunistically when observed on birds. Blood and feather samples were tested for BFDV by PCR, and a subset of samples was tested for the presence of antibodies to BFDV using the haemagglutination inhibition test. Skin was processed routinely for histopathology and examined under light microscopy for evidence of BFDV as well as other causes of feather loss. The prevalence of feather loss in the study population changed substantially during the 2 year project, from 0% (95%CI: 0-6.7%) in April 2011, up to 45% (95%CI: 32.0-58.5%) in September 2012. This feather loss was predominantly around the head and neck region, with varying degrees of hyperkeratosis and lichenification evident on physical exam. BFDV was detected only in the first sampling session at 4% prevalence (95%CI: 0.5-13.0%), and was not correlated with clinical signs. A mite was detected in skin biopsies of all birds showing signs of feather loss and, increasingly, in skin biopsies from birds not showing changes to feathering. Examination of hippoboscid flies revealed female mites and eggs on the abdomen. The characteristic feather loss associated with this mite has been observed in other populations of RCP, as well as in several populations of the orange fronted parakeet. Continued monitoring of the study population is recommended to broaden our understanding of the factors that underpin the host-parasite relationship, and produce survival data to infer the impacts of this parasite on viability at individual and population scales.

Tiritiri Matangi Island in the Hauraki Gulf region of Auckland is an open sanctuary with a reintroduced population of kakariki (red crowned parakeets, Cyanoramphus novaezelandiae). These birds originally came from captivity in the 1970's. For the past decade, there have been increasing reports of feather loss in this species on the island. In 2008, beak and feather disease virus (BFDV) was detected nearby on Hauturu island, and therefore it was suspected the feather loss might have been due to a spread of this pathogen. However, a 2-year study into health and disease of red crowned parakeets on Tiritiri Matangi has revealed a different source of the clinical signs. During four cross sectional studies from 2011-12, feather loss increased from 8% (95%CI:2.3%-18.8%) up to 52% (95%(1:38.6%-65.2%) of the population. Skin biopsies from all birds in the second year of the study found a skin mite associated with thickening of the skin (acanthosis) and excessive keratin production (hyperkeratosis). Mites were also found in asymptomatic birds, suggesting a subclinical or carrier status. Whole mites were cleared in Hoyer's medium, with larval and female forms of Procnemidocoptes jansseni identified. This mite has only been formerly described in a lovebird from Zambia (Fain 1966), raising questions as to how it came to be present in wild kakariki in New Zealand. Another skin mite Hemimyialges macdonaldi, also reported to cause mange, was found in low numbers from skin as well as on hippoboscid flies removed from several birds. The relationship between the cosmopolitan H.macdonaldi, the dominant mite P.jansseni, and the clinical signs of mange requires further investigation. New Zealand is host to a unique avifauna, which has been significantly affected by the combined impacts of habitat modification and introduced mammalian predators. Many now thrive only on offshore islands or predator-free mainland sanctuaries, with ongoing conservation efforts reliant on re-introductions and translocations between these sites. These assisted movements, which may include periods of captive management, introduce specific biosecurity risks and potential for artificial spread of pathogens and parasites. Historically these activities took place in the absence of extensive or strategic disease screening, or prior to our current understanding of, or capacity to detect, key diseases. Results from this study will feed into captive and wild management of kakariki, specifically identifying new risks for translocations and re-introduction programs. The study also highlights the importance of epidemiological approaches to studying disease syndromes in wild populations.

There has been an alarming and dramatic decline in small to medium sized native mammal species in northern Australia over the past 20 years. The causes of this decline are currently under investigation. There is limited historical and/or current information on health and disease in northern Australian mammal species and it is not known what role disease may be playing in the decline of mammals in northern Australia. The project objective is to investigate the potential role of disease in the declines of mammal species in northern Australia, focussing on the Top End of the Northern Territory. If species declines continue, then mammal populations will become more isolated; genetic diversity of species will diminish and faunal communities will change. Under these circumstances, the negative impacts of disease will increase. It is therefore vital to understand not only the role that disease may be playing in mammal declines at present, but also to gain understanding of the likely impacts of disease into the future. The disease investigation project will focus field research efforts on four main sites within the Top End: Kakadu National Park, Bathurst Island, Garig Gunak Barlu National Park on the Cobourg Peninsula and peri-urban areas around Darwin. Other potential study sites include remote islands, west Amhern Land and collaborative northern quail study sites in Kakadu NP. Logistics dictate an initial focus on one species from each major taxonomic group undergoing decline: Brush-tailed possum (Trichosurus vulpecula); Northern brown bandicoot (Isoodon macrourus); Northern quail (Dasyurus hallucatus ); Brush-tailed rabbit-rat (Conilurus penicillatus). Golden bandicoots (Isoodon auratus) may be targeted however sample size is likely to be limited. Feral species such as black rats (Rattus rattus) and cats (Felis catus), as well as abundant native species, will also be tested including fresh carcasses. Compromised individuals of any native species will be sampled, including post mortem examination of carcases. Animals will be trapped during routine fauna surveys and examined and sampled. A wide range of biological samples will be collected (generally under field anaesthesia) and submitted for health and disease screening. This is a strongly collaborative project drawing on support from a wide range of researchers across Australia. Results of the first two surveys (Cobourg Peninsula July 2013 and Bathurst Island September 2013) will be presented.