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RESEARCH ARTICLE
Contents Vol 33(1)

Change in the diet of sooty owls (Tyto tenebricosa) since European settlement: from terrestrial to arboreal prey and increased overlap with powerful owls

Rohan J. Bilney A , Raylene Cooke A B and John White A
+ Author Affiliations
- Author Affiliations

A School of Life & Environmental Sciences, Deakin University, 221 Burwood Highway, Burwood, Vic. 3125, Australia.

B Corresponding author. Email: raylene.cooke@deakin.edu.au

Wildlife Research 33(1) 17-24 https://doi.org/10.1071/WR04128
Submitted: 20 December 2004  Accepted: 29 November 2005   Published: 7 March 2006

Abstract

The current diet of the sooty owl (Tyto tenebricosa) was determined by analysing freshly regurgitated pellets collected beneath their roosting sites in East Gippsland, Victoria. Comparisons were then made with: (i) prehistoric and historic diet from bone deposits found in cave roosts, and (ii) diet of a sympatric owl species, the powerful owl (Ninox strenua). Sooty owls consumed a large array of terrestrial mammal species before European settlement, but only three terrestrial species were detected in their current diet, a reduction of at least eight species since European settlement. To compensate, sooty owls have increased their consumption of arboreal prey from 55% to 81% of their diet. Arboreal species are also a major component of the powerful owl diet and this prey shift by sooty owls has increased dietary overlap between these two species. Predation by foxes (Vulpes vulpes) and other feral species is likely to have reduced the amount of terrestrial prey available to sooty owls since European settlement. Investigation of changes in the diet of sooty owls may offer a unique monitoring system for evaluating the ability of fox-control strategies to influence increases in numbers of critical-weight-range mammals.


Acknowledgments

We thank Andy Murray for information and advice on fox-baiting strategies in the study area. Bill Peel and John Burns are thanked for advice on rainforest locations and Ken Aplin is thanked for his assistance with historical bone identification. Julie and Bob Hollingsworth are also thanked for providing information on the Nicholson River powerful owls and the Goldsmith family for giving permission to access their property. Roger, Carolyn and Adam Bilney, Rob Grant, Fiona Hogan, Peter Kambouris and David Hollands are thanked for support in the field and the advice they so willingly provided. This research was undertaken with permits 10002313 and 10002809 from the Department of Sustainability and Environment.


References

Baird R. F. (1996). The taphonomy of Lake Quaternary cave localities yielding vertebrate remains in Australia. In ‘Vertebrate Palaeontology of Australia’. (Eds P. Vickers-Rich, J. M. Monaghan, R. F. Baird and T. H. Rich.) (Monash University Publications Committee: Melbourne.)

Barrett G., Silcocks A., Barry S., Cunningham R., and Poulter R. (2003). ‘The New Atlas of Australian Birds.’ (RAOU: Melbourne.)

Blakers M., Davies S. J. J. F., and Reilly P. N. (1984). ‘The Atlas of Australian Birds.’ (RAOU & Melbourne University Press: Melbourne.)

Brown, G. W. , and Triggs, B. E. (1990). Diets of wild canids and foxes in east Gippsland 1983–1987, using predator scat analysis. Australian Mammalogy 13, 209–213.
Brunner H., and Coman B. J. (1974). ‘The Identification of Mammalian Hair.’ (Inkata Press: Melbourne.)

Burbidge, A. A. , and McKenzie, N. L. (1989). Patterns in the modern decline of Western Australia’s vertebrate fauna: causes and conservation implications. Biological Conservation 50, 143–198.
| Crossref | GoogleScholarGoogle Scholar | Clarke K. R., and Warwick R. M. (1994). ‘Change in Marine Communities: an Approach to Statistical Analysis and Interpretation.’ (Plymouth Marine Laboratory: Plymouth, UK.)

Cooke, R. , Wallis, R. , Webster, A. , and Wilson, J. (1997). Diet of a family of powerful owls (Ninox strenua) from Warrandyte, Victoria. Proceedings of the Royal Society of Victoria 109, 1–6.
Cooke R., Wallis R., and Webster A. (2002). Urbanisation and the ecology of powerful owls (Ninox strenua) in outer Melbourne, Victoria. In ‘Ecology and Conservation of Owls’. (Eds I. Newton, R. Kavanagh, J. Olsen and I. Taylor.) pp. 101–106. (CSIRO Publishing: Melbourne.)

Debus, S. J. S. (1994). The sooty owl (Tyto tenebricosa) in New South Wales. Australian Birds 28, 4–19.Supplement
Green R. H. (1983). ‘An Illustrated Key to the Skulls of the Mammals in Tasmania.’ (Queen Victoria Museum and Art Gallery: Launceston.)

Hall L. S. (1977). A recent bone deposit at Marble Arch, N.S.W. In ‘Australian Speleological Federation Proceedings. 10th Biennial Conference, 1977: Section 3, Palaeontology, Biology, Anthropology, Australia’. (Ed. A. W. Graham.) pp. 35–46. (Speleological Federation: Canberra.)

Hayward, G. D. , and Garton, E. O. (1988). Resource partitioning among forest owls in the River of No Return Wilderness, Idaho. Oecologia 75, 253–265.
| Crossref | GoogleScholarGoogle Scholar | Hollands D. (1991). ‘Birds of the Night.’ (Reed Books: Sydney.)

Holmes, G. (1994). Prey of the sooty owl in subtropical Australia. Sunbird 24, 25–27.
Kavanagh R. P. (1997). Ecology and management of large forest owls in south-eastern Australia. Ph.D. Thesis, University of Sydney.

Kavanagh R. P. (2002). Comparative diets of the powerful owl (Ninox strenua), sooty owl (Tyto tenebricosa) and masked owl (Tyto novaehollandiae) in southeastern Australia. In ‘Ecology and Conservation of Owls’. (Eds I. Newton, R. Kavanagh, J. Olsen and I. Taylor.) pp. 175–191. (CSIRO Publishing: Melbourne.)

Kavanagh R. P. (2004). Conserving owls in Sydney’s urban bushland: current status and requirements. In ‘Urban Wildlife More than Meets the Eye’. (Eds D. Lunney and S. Burgin.) pp. 93–108. (Royal Zoological Society of New South Wales.)

Lack, D. (1946). Competition for food by birds of prey. Journal of Animal Ecology 15, 123–129.
Menkhorst P. W. (1995). ‘Mammals of Victoria. Distribution, Ecology and Conservation.’ (Oxford University Press: Melbourne.)

Mooney N. (1993). Diet of the masked owl in Tasmania: past and present. In ‘Australian Raptor Studies’. (Ed. P. Olsen.) pp. 160–174. (RAOU: Melbourne.)

Morris, D. A. , Augee, M. L. , Gillieson, D. , and Head, J. (1997). Analysis of a late Quaternary deposit and small mammal fauna from Nettle Cave, Jenolan, New South Wales. Proceedings of the Linnean Society of New South Wales 117, 135–162.
Peel B. (1999). ‘Rainforests and Cool Temperate Mixed Forests of Victoria.’ (Department of Natural Resources and Environment: Melbourne.)

Short, J. , and Smith, A. (1994). Mammal decline and recovery in Australia. Journal of Mammalogy 75, 288–297.
Strahan R. (1995). ‘The Mammals of Australia.’ (Reed Books: Sydney.)

Tilley, S. (1982). The diet of the powerful owl (Ninox strenua) in Victoria. Australian Wildlife Research 9, 157–175.
| Crossref | GoogleScholarGoogle Scholar | Triggs B. (2001). ‘Tracks, Scats and Other Traces: a Field Guide to Australian Mammals.’ (Oxford University Press: Melbourne.)

Triggs, B. , Brunner, H. , and Cullen, J. M. (1984). The food of the fox, dog and cat in Croajingalong National Park, south-eastern Victoria. Australian Wildlife Research 11, 491–499.
| Crossref | GoogleScholarGoogle Scholar |

Wakefield, N. A. (1960a). Recent mammal bones in the Buchan district – 1. Victorian Naturalist 77, 164–178.


Wakefield, N. A. (1960b). Recent mammal bones in the Buchan district – 2. Victorian Naturalist 77, 227–240.


Wakefield, N. A. (1967). Mammal bones in the Buchan District. Victorian Naturalist 84, 211–213.


Wakefield, N. A. (1972). Palaeoecology of fossil mammal assemblages from some Australian caves. Proceedings of the Royal Society of Victoria 85, 1–26.


Wallis, R. L. , and Brunner, H. (1987). Changes in mammalian prey of foxes (Vulpes vulpes) (Carnivora: Canidae) over 12 years in a forest park near Melbourne, Victoria. Australian Mammalogy 10, 43–44.


Wallis, R. , Cooke, R. , and Webster, A. (1998). Diet of powerful owls in the Yarra Valley, Victoria. Australian Bird Watcher 17, 395–397.


Wilson, B. A. , and Friend, G. R. (1999). Responses of Australian mammals to disturbance: a review. Australian Mammalogy 21, 87–105.