veterinary_and_life_sciences_ced_960x100_populated.jpg
Black Cockatoo

Health status and population demographics of free-living endangered black cockatoos (Calyptorhynchus spp.) in Western Australia

Dr Kris Warren, Dr Carly Holyoake and Dr Mike Calver – Murdoch University, Dr Anna Le Souef and Dr Simone Vitali – Perth Zoo, Dr Hillar Klandorf – University of West Virginia, Rick Dawson, Keith Morris and Dr Peter Mawson - Department of Environment and Conservation

This three year study is being conducted by Murdoch University as a collaborative project with the Department of Environment and Conservation, Perth Zoo and University of West Virginia with support from Newmont Boddington Gold, BHP Billiton Worsley Alumina and the Department of Environment and Conservation.   

Aims:

  1. To determine the ages using pentosidine analysis of wild injured and debilitated black cockatoos admitted for treatment to the Perth Zoo Veterinary Department during 2011-2013.
  2. To produce reference ranges for haematology and serum biochemistry for free-living black cockatoo nestlings.
  3. To compare haematological and serum biochemical ranges for nestlings from different geographical sites and between nesting seasons.
  4. To determine the prevalence of psittacine beak and feather disease virus (BFDV), avian polyomavirus (APV) and Chlamydophila psittaci infection amongst free-living black cockatoo nestlings.
  5. To test nest material for the presence of viral antigen (BFDV and polyomavirus).
  6. To determine the sex using DNA methods of a sample of free-living black cockatoo nestlings.
  7. To identify any ectoparasites seen on the nestlings during sampling studies.
  8. To screen the faeces of nestlings to identify any gastrointestinal parasites that may be present.

Significance and General Description

The three species of black cockatoo endemic to the south-west of Western Australia (Carnaby’s cockatoo Calyptorhynchus latirostris, Baudin’s cockatoo Calyptorhynchus baudinii and red-tailed black cockatoo Calyptorhynchus banksii) face population declines as a result of several threatening factors including habitat loss and fragmentation, poaching for the pet trade, competition with other species for nesting hollows, vehicle strikes and shootings.  The Perth Zoo Veterinary Department has collaborated with the Department of Environment and Conservation (DEC) since 2000 in an effort to provide specialised care for endangered black cockatoos requiring rehabilitation.  Each year over 100 cockatoos are presented through DEC to the Veterinary Department.  The program contributes significantly to the conservation of the species through the release of rehabilitated birds, captive breeding and public education.  It also provides a unique opportunity to study the admitted birds to gain a greater understanding of the health and disease status of the wild populations.

One of the major concerns regarding wild populations of black cockatoos is that due to declining recruitment rates, the average age of wild flocks is increasing and many birds may be past breeding age.  If this is true, then there may be a catastrophic population crash when the older birds die.  It is currently impossible to age most birds, including black cockatoos, once they reach sexual maturity because of the lack of outward signs of aging.  The ability to age endangered black cockatoos would be invaluable, as it would provide information both on the life histories of cockatoos admitted to the Perth Zoo Veterinary Department, as well as age demographics of wild cockatoos.  This aging tool would have wide implications for other researchers too, for example to provide insight into life cycles and population fluxes of black cockatoos, and to aid in the species recovery programs.

Pentosidine is a compound formed during the process of nonenzymatic glycation, which has been found to accumulate linearly in the collagen of birds over time (Chaney et al. 2003).  The measurement of pentosidine in bird skin has already led to the creation of a number of ‘wild bird curves’ to determine ages of birds of unknown age.  Skin samples have been taken from a range of known-aged black cockatoos during recent PhD studies by Dr Anna Le Souëf from Murdoch University, and sent to the Division of Animal and Veterinary Sciences at West Virginia University to create an age curve for the genus Calyptorhynchus.  The levels of pentosidine in the skin biopsies from the wild cockatoos taken during this study will be read against the curve to determine the ages of the wild birds, with an accuracy of 1-2 years.  These data will then be analysed to determine the age spread of birds admitted to the Perth Zoo Veterinary Department from the wild.

A second major component of this study will focus on the health investigation of free-living black cockatoo nestlings in the south-west of Western Australia.  DEC performs regular monitoring checks of black cockatoo nests, but there have been no disease testing or health studies performed on wild black cockatoos.  As a result there is very little known about the health status of wild black cockatoos.  Conservation biologists are increasingly recognising the role of disease as a limiting factor in species survival (Deem et al. 2001), particularly as anthropogenic changes increasingly influence the health of endangered populations.  As an example, local weather effects associated with climate change may cause disease problems such as increased parasitism and therefore alter population dynamics (Antoniazzi et al. 2010).  In recent years there have been an increasing number of studies of free-living avian species (Hernandez et al. 1990; Gilardi et al. 1995; de Freitas Raso et al. 2006; Deem et al. 2008; Masello et al. 2009).  Such studies are critical components of conservation programs for endangered psittacines as they provide baseline data.  Baseline data are important for comparisons in the event of various disturbances (e.g. habitat loss, weather extremes, disease outbreaks) which may affect the population and for comparison between different populations (Deem et al. 2001; Allgayer et al. 2009).  Additionally, if captive breeding programs form part of recovery efforts, then the disease status of both captive and free-living populations should be understood before considering the release of captive-bred birds. 

The three diseases that will be investigated during this study (psittacine beak and feather disease virus, avian polyomavirus  and Chlamydophila psittaci infection) are significant in captive and free-living populations of psittacine birds (Gilardi et al. 1995; Ortiz-Catedral et al. 2009).  Psittacine beak and feather disease is a highly contagious and potentially fatal disease of parrots, that has been detected in free-living populations of several Australian psittacine birds (Raidal et al. 1993).  It can become an additional threatening factor among endangered psittacines and is therefore of concern for conservation biologists and wildlife managers (Ortiz-Catedral et al. 2009).  APV is another serious viral disease that is well known for its tendency to infect budgerigar fledglings (Bernier et al. 1981) with mortality rates of up to 100% (Kaleta et al. 1984), and which can infect a number of other psittacine species (Enders et al. 1997).  C. psittaci is a bacterium commonly found in psittacine birds.  It may cause debilitating clinical disease with respiratory and gastrointestinal signs, but the infection may also be carried subclinically and be reactivated when the bird is immunocompromised.  In wild populations C. psittaci can cause devastating declines, particularly under certain conditions, such as when disturbances to natural habitat occur (de Freitas Raso et al. 2006).

Health data from wild birds are rare, due to the difficulty in obtaining samples (Masello and Quillfeldt 2004); therefore it is important to maximise opportunities for sample collection.  The routine nest checks performed by DEC during the cockatoo breeding season, during which chicks are briefly removed from their nests for morphometric measurements, provide a valuable chance to collect samples for health assessment.  The sample collection is unlikely to significantly prolong the handling of the chicks.

It should be noted that all aspects of the field work are covered by DEC and Murdoch University ethics permits.

References

  • Allgayer, M. C., Guedes, N. M., Chiminazzo, C., Cziulik, M., and Weimer, T. A. 2009. Clinical pathology and parasitologic evaluation of free-living nestlings of the Hyacinth Macaw (Anodorhynchus hyacinthinus). Journal of Wildlife Diseases 45 (4):972-981.
  • Antoniazzi, L., Manzoli, D., Rohrmann, D., Saravia, M., Silvestri, L., and Beldomenico, P. 2010. Climate variability affects the impact of parasitic flies on Argentinean forest birds. Journal of Zoology Published online 27 September 2010.
  • Australian Government. 1999. Environment Protection and Biodiversity Act (EPBC Act). Canberra, Australia.
    Bernier, G., Morin, M., and Marsolais, G. 1981. A generalized inclusion body disease in the budgerigar (Melopsittacus undulatus) caused by a papovavirus-like agent. Avian Dis 25 (4):1083-1092.
  • Chaney, R., Blemings, K., Bonner, J., and Klandorf, H. 2003. Pentosidine as a measure of chronological age in wild birds. The Auk 120 (2):394-399.
    de Freitas Raso, T., Seixas, G. H., Guedes, N. M., and Pinto, A. A. 2006. Chlamydophila psittaci in free-living Blue-fronted Amazon parrots (Amazona aestiva) and Hyacinth macaws (Anodorhynchus hyacinthinus) in the Pantanal of Mato Grosso do Sul, Brazil. Veterinary Microbiology 117 (2-4):235-241.
    Deem, S., Karesh, W., and Weisman, W. 2001. Putting theory into practice: wildlife health in conservation. Conservation Biology 15 (5):1224-1233.
    Deem, S. L., Ladwig, E., Cray, C., Karesh, W. B., and Amato, G. 2008. Health assessment of the ex situ population of St Vincent parrots (Amazona guildingii) in St Vincent and the Grenadines. Journal of Avian Medicine and Surgery 22 (2):114-122.
  • Enders, F., Gravendyck, M., Gerlach, H., and Kaleta, E. F. 1997. Fatal avian polyomavirus infection during quarantine in adult wild-caught red-faced lovebirds (Agapornis pullaria). Avian Diseases 41 (2):496-498.
  • Gilardi, K. V., Lowenstine, L. J., Gilardi, J. D., and Munn, C. A. 1995. A survey for selected viral, chlamydial, and parasitic diseases in wild dusky-headed parakeets (Aratinga weddellii) and tui parakeets (Brotogeris sanctithomae) in Peru. Journal of Wildlife Diseases 31 (4):523-528.
    Government of Western Australia. 1950. Western Australian Wildlife Conservation Act. Perth, Australia.
  • Hernandez, M., Martin, S., and Fores, P. 1990. Clinical hematology and blood chemistry values for the common buzzard (Buteo buteo). Journal of Raptor Research 24 (4):113-119.
  • Kaleta, E. F., Herbst, W., Kaup, F., Jank-Ludwig, R., Marschall, H., Drommer, W., and Krautwald, M. 1984. Investigations on the viral aetiology of a disease of budgerigars (Melopsittacus undulatus) with hepatitis and feather disorders. Journal of Veterinary Medicine 31:219-224.
  • Masello, J. F., Choconi, R., Helmer, M., Kremberg, R., Lubjuhn, T., and Quillfeldt, P. 2009. Do leucocytes reflect condition in nestling burrowing parrots Cyanoliseus patagonus in the wild? Comparative Biochemistry and Physiology, Part A 152:176-181.
  • Masello, J. F., and Quillfeldt, P. 2004. Are haematological parameters related to body condition, ornamentation and breeding success in wild burrowing parrots Cyanoliseus patagonus? Journal of Avian Biology 35:445-454.
  • Ortiz-Catedral, L., McInnes, K., Hauber, M., and Brunton, D. 2009. First report of beak and feather disease virus (BFDV) in wild Red-fronted Parakeets (Cyanoramphus novaezelandiae). Emu 109:244-247.
  • Raidal, S. R., McElnea, C. L., and Cross, G. M. 1993. Seroprevalence of psittacine beak and feather disease in wild psittacine birds in New South Wales. Aust Vet J 70 (4):137-139.
  • Weiss, D., and Wardrop, K. 2010. Schalm's Veterinary Hematology: 6th edition. New Jersey: John Wiley and Sons.

Department of Environment and ConservationPerth ZooNewmont Asia Pacificbhp billiton