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RESEARCH ARTICLE
Contents Vol 107(3)

Home-range of the Powerful Owl (Ninox strenua) in dry sclerophyll forest

Todd Soderquist A C and Dale Gibbons B
+ Author Affiliations
- Author Affiliations

A Arthur Rylah Institute, Victorian Department of Sustainability and Environment, 123 Brown St, Heidelberg, Vic. 3084, Australia.

B Eiles Road, Maiden Gully, Vic. 3551, Australia.

C Corresponding author. Present address: Biodiversity Conservation Unit, NSW Department of Environment and Conservation, PO Box 494, Armidale, NSW 2350, Australia. Email: todd.soderquist@environment.nsw.gov.au

Emu 107(3) 177-184 https://doi.org/10.1071/MU06055
Submitted: 6 November 2006  Accepted: 24 May 2007   Published: 31 August 2007

Abstract

Since European settlement of Australia, the dry open forests and woodlands of central Victoria have been extensively cleared and most large trees harvested, resulting in a decline of arboreal mammal populations. The Powerful Owl, which was formerly reliant on these prey species, still persists in the region but at very low densities and uncertain viability. Previous research has shown that Powerful Owls select home-ranges with more large trees and hollows than the forest at large, but the amount of such habitat that is required remained undefined. Four adult Powerful Owls (two males and two females) from four pairs occupying geographically separate territories in box-ironbark forest were radio-tracked over 1–6 months. Home-range size was much greater than previously assumed for this species (minimum convex polygon of 4774, 2896, 1770 and 1382 ha). Range-length was 5.7–8.9 km, and on average 5–12% of each home-range was used during a single night. Core foraging areas comprised many, typically small, patches scattered across the entire home-range. Selection of roosting sites was flexible and did not constrain spatial use of home-range, with 96% of roosts in very small to medium-sized trees, which are widely distributed. The finding of unexpectedly large foraging ranges suggests that enhancement of habitat quality and mammalian prey abundance in currently occupied home-ranges is the foremost goal for forest managers if a viable population is to be sustained.


Acknowledgments

This research was funded through the Commonwealth Regional Forests Agreement process and conducted under permits and ethics approvals granted by the Victorian Department of Sustainability and Environment (then DNRE). We thank Kim Lowe, Richard Loyn and Rob Price for their help throughout the study. The study benefited from insights provided by Steve Craig, Barry Traill, Ed McNabb, Rod Kavanagh, Alan Webster and Paul Peake. Janet Gardner and Sarah Legge suggested key improvements to the net design, and Brian Cresswell has long assisted with radio-tag construction. Natasha Schedvin provided support on numerous fronts, all much appreciated. Thanks are also owed to the Owls themselves, who tolerated our invasion of their lives … however disdainfully.


References

Bingham, B. B. , and Noon, B. R. (1998). The use of core areas in comprehensive mitigation strategies. Conservation Biology 12, 241–243.
| Crossref | GoogleScholarGoogle Scholar | Davey S. M. (1993). Notes on the habitat of four Australian owl species. In ‘Australian Raptor Studies’. (Ed. P. Olsen.) pp.126–142. (Royal Australasian Ornithologists Union: Melbourne.)

Deacon, J. N. , and Mac Nally, R. (1998). Local extinction and nestedness of small-mammal faunas in fragmented forest of central Victoria, Australia. Pacific Conservation Biology 4, 122–131.
ECC (1997). ‘Box-Ironbark Forests and Woodlands Investigation, Resources and Issues Report.’ (Environment Conservation Council: Melbourne.)

Elody, B. I. , and Sloan, N. F. (1984). A mist-net technique useful for capturing barred owls. North American Bird Bander 9, 13–14.
Fleay D. (1968). ‘Nightwatchmen of Bush and Plain.’ (Jacaranda Press: Brisbane.)

Harris, S. , Cresswell, W. J. , Forde, P. G. , Trewhella, W. J. , Woollard, T. , and Wray, S. (1990). Home-range analysis using radiotracking data – a review of problems and techniques particularly as applied to the study of mammals. Mammal Review 20, 97–123.
Higgins P. J. (Ed.) (1999). ‘Handbook of Australian, New Zealand and Antarctic Birds. Vol. 4: Parrots to Dollarbird.’ (Oxford University Press: Melbourne.)

Holland G. , and Cheers G. (1999). ‘Identification of Large Old Tree Sites and Fauna Refuges in the ECC’s Box-Ironbark Study Area.’ (Natural Resources and Environment: Melbourne.)

Hollands D. (1991). ‘Birds of the Night: Owls, Frogmouths and Nightjars of Australia.’ (Reed Books: Sydney.)

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 a). Conservation and management of large forest owls in southeastern Australia. In ‘Ecology and Conservation of Owls’. (Eds I. Newton, R. Kavanagh, J. Olsen and I. Taylor.) pp. 201–219. (CSIRO Publishing: Melbourne.)

Kavanagh R. P. (2002 b). 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 NSW: Sydney.)

Kavanagh R. P. , and Jackson R. (1997). Home-range, movements, habitat and diet of the Sooty Owl Tyto tenebricosa near Royal National Park, Sydney. In ‘Australian Raptor Studies II’. (Eds G. Czechura and S. Debus.) pp. 2–13. (Birds Australia: Melbourne.)

Kavanagh, R. P. , and Murray, M. (1996). Home range, habitat and behaviour of the Masked Owl Tyto novaehollandiae near Newcastle, New South Wales. Emu 96, 250–257.
| Crossref | GoogleScholarGoogle Scholar | Kavanagh R. P. , and Peake P. (1993). Distribution and habitats of nocturnal forest birds in south-eastern New South Wales. In ‘Australian Raptor Studies’. (Ed. P. Olsen.) pp.101–125. (Royal Australasian Ornithologists Union: Melbourne.)

Kenward R. (1987). ‘Wildlife Radio Tagging.’ (Academic Press: London.)

Kenward, R. E. , Clarke, R. T. , Hodder, K. H. , and Walls, S. S. (2001). Distance and density estimators of home range: defining multi-nuclear cores by nearest neighbor clustering. Ecology 82, 1905–1920.
| Crossref | GoogleScholarGoogle Scholar | Kenward R. E. , South A. B. , and Walls S. S. (2003). Ranges6 Version 1.2. (Anatrack Ltd, Wareham, UK.)

Kernohan B. J. , Gitzen R. A. , and Millspaugh J. J. (2001). Analysis of animal space use and movements. In ‘Radio Tracking and Animal Populations’. (Eds. J. J. Millspaugh and J. M. Marzluff.) pp. 125–166. (Academic Press: San Diego, CA.)

Lawson, E. J. G. , and Rodgers, A. R. (1997). Differences in home range size computed in commonly used software programs. Wildlife Society Bulletin 25, 721–729.
Meredith C. W. (1984). Possums or poles? – the effect of silvicultural management on the possums of Chiltern State Park, northeast Victoria. In ‘Possums and Gliders’. (Eds A. P. Smith and I. D. Hume.) pp. 575–577. (Australian Mammal Society: Sydney.)

Muir A. M. , Edwards S. A. , and Dickins M. J. (1995). Description and conservation status of the Vegetation of the Box-Ironbark Ecosystem in Victoria. Flora and Fauna Technical Report No. 136, Conservation and Natural Resources, Melbourne.

Paton, P. W. C. , Zabel, C. J. , Neal, D. L. , Steger, G. N. , Tilghman, N. G. , and Noon, B. R. (1991). Effects of radio tags on spotted owls. Journal of Wildlife Management 55, 617–622.
| Crossref | GoogleScholarGoogle Scholar | Soderquist T. R. (1999). Tree hollows in the box-ironbark forest. Forests Service Technical Report 99–3, Natural Resources and Environment, Melbourne.

Soderquist, T. R. , and Mac Nally, R. (2000). The conservation value of mesic gullies in dry forest landscapes: mammal populations in the box-ironbark system of southern Australia. Biological Conservation 93, 281–291.
| Crossref | GoogleScholarGoogle Scholar | Soderquist T. , and Rowley L. (1995). Mature Tree Sites in the Bendigo Forest Management Area. (Natural Resources and Environment: Bendigo, Victoria.)

Soderquist T. , Lowe K. , Loyn R. , and Price R. (2002). Habitat quality of powerful owl territories in box-ironbark forest of Victoria, Australia. In ‘Ecology and Conservation of Owls’. (Eds I. Newton, R. Kavanagh, J. Olsen and I. Taylor.) pp. 91–99. (CSIRO Publishing: Melbourne.)

Traill B. J. (1991). Box-ironbark forests: tree hollows, wildlife and management. In ‘Conservation of Australia’s Forest Fauna’. (Ed. D. Lunney.) pp. 119–123. (Royal Zoological Society of New South Wales: Sydney.)

Traill B. J. (1993). The diet and movements of a pair of Powerful Owls Ninox strenua in dry eucalypt forest. In ‘Australian Raptor Studies’. (Ed. P. Olsen.) pp.155–159. (Royal Australasian Ornithologists Union: Melbourne.)

Webster A. , Humphries R. , and Lowe K. (1999). ‘Powerful Owl Ninox strenua Action Statement No. 92.’ (Natural Resources and Environment: Melbourne.)