Development and improvement of clinical tools for rehabilitating endangered black cockatoos (Calyptorhynchus spp.) back to the wild
Le Souëf, Anna (2013) Development and improvement of clinical tools for rehabilitating endangered black cockatoos (Calyptorhynchus spp.) back to the wild. PhD thesis, Murdoch University.
Black cockatoos (Calyptorhynchus spp.) in the ‘biodiversity hotspot’ of south-west Western Australia are in decline, due to multiple threatening processes that include habitat loss, poaching, competition with other species, vehicle strikes and shootings. The combined efforts of the Perth Zoo Veterinary Department (PZVD) and the Western Australian Department of Environment and Conservation (DEC) have led to a specialised rehabilitation program centred upon the return of injured and debilitated black cockatoos to the wild. This PhD project focused on improving the efficacy of this program and expanding the current knowledge of the health status and biology of black cockatoos.
The medical records of 565 black cockatoos that were admitted to the PZVD from 2000 to 2009 were analysed to determine the effect of the birds’ clinical presentation on survival. Anaemia, superficial and deep soft tissue injuries, fractures, paralysis or paresis and abnormal faecal cytology were identified as significant factors when determining the likelihood of survival of cockatoos undergoing the rehabilitation process. In addition, data on the life histories and origin of admitted cockatoos, post-mortem examination results and post-release information is presented. Haematologic and serum biochemical reference values are also presented for the three species of black cockatoos that are regularly admitted to the PZVD.
The significance of Chlamydia psittaci infection to the black cockatoo rehabilitation program was investigated. No wild birds admitted to the PZVD were found to be positive for C. psittaci infection, which suggests that this infection either is not present in wild populations, or has a low prevalence. However, the study found that black cockatoos undergoing rehabilitation are at risk of contracting the disease during their stay in captivity through contact with infected birds. These results highlight the importance of disease surveillance to the management of an avian rehabilitation program.
The thesis includes the results of an aviary trial to investigate methods of attaching transmitters to black cockatoos. Mean retention times for the transmitter packages ranged from 44 to 384 days. These results support the potential feasibility of using transmitters on cockatoos post-release, with sufficient retention times to allow for the collection of valuable movement and survival data.
Among the gaps in current knowledge of wild black cockatoos, perhaps the most concerning is that regarding the age structure of wild populations. The thesis encompasses a study that established an aging tool for black cockatoos, based on pentosidine analysis from the skin of 53 black cockatoos of known age. The result is a vital first step towards understanding the population dynamics of wild black cockatoos, and will help provide further information about the life histories of cockatoos admitted to the PZVD following injury or debilitation.
|Publication Type:||Thesis (PhD)|
|Murdoch Affiliation:||School of Veterinary and Life Sciences|
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