Register      Login
Wildlife Research Wildlife Research Society
Ecology, management and conservation in natural and modified habitats
Shopping Cart: ( empty )
You are here: Home > Journals > WR > WR07075
RESEARCH ARTICLE
Contents Vol 35(4)

Aerial mark–recapture estimates of wild horses using natural markings

Michelle J. Dawson A C and Cameron Miller B
+ Author Affiliations
- Author Affiliations

A Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601 Australia.

B Parks Victoria, Level 9, 535 Bourke St, Melbourne, Vic. 3000, Australia. Present address: SMEC Australia, Level 5, 71 Queens Parade, Melbourne, Vic. 3004, Australia.

C Corresponding author. Email: wildeye@netspeed.com.au

Wildlife Research 35(4) 365-370 https://doi.org/10.1071/WR07075
Submitted: 27 June 2007  Accepted: 23 January 2008   Published: 27 June 2008

Abstract

Aerial mark–recapture population estimates utilising the natural markings of wild horses to identify individuals was applied in the Bogong High Plains, Alpine National Park, Victoria. A discrete population of wild horses occupying an area of 180 km2 was sampled over two days in 2005. This study explored the feasibility of a technique that aimed to enable managers to estimate the size of the horse population and monitor it over time. Four observers (including the pilot) searched for horses from a helicopter. Once horses were sighted, photographic and written observations were used to ‘mark’ each animal. The survey was repeated the following day with observations ‘recapturing’ individuals. Data were analysed using several mark–recapture estimators, and the derived population estimates ranged from 89 (±5.3, s.e.) horses to 94.7 (±7.9, s.e.) horses. We found that the method gave a level of precision relevant to management, but needs refinement. The technique and its assumptions should be tested further by increasing the number of samples and video should be used to improve identification of individuals. We believe that this is a novel application for aerial surveys, which are typically unsuitable for estimating the size of small populations. This technique was developed for horses but may be used on other conspicuous species with unique natural markings.


Acknowledgements

We thank Parks Victoria for funding the survey, Colleen Nagle and Enzo Brotto from Parks Victoria for participating in the aerial survey and the pilot David Empey for keeping us safe. We also thank James Dawson for reviewing a draft of this manuscript, and three anonymous referees who provided valuable input to the final draft.


References

Berger J. (1986). ‘Wild Horses of the Great Basin. Social Competition and Population Size.’ (University of Chicago Press: Chicago, IL.)

Buckland S. T., Anderson D. R., Burnham K. P., and Laake J. L. (1993). ‘Distance Sampling: Estimating Abundance of Biological Populations.’ (Chapman and Hall: London.)

Caughley, G. , and Grice, D. (1982). A correction factor for counting emus from the air, and its application to counts in Western Australia. Australian Wildlife Research 9, 253–259.
| Crossref | GoogleScholarGoogle Scholar | Caughley G., and Sinclair A. R. E. (1994). ‘Wildlife Ecology and Management.’ (Blackwell: Cambridge.)

Caughley, G. , Sinclair, R. , and Scott-Kemmis, D. (1976). Experiments in aerial survey. Journal of Wildlife Management 40, 290–300.
| Crossref | GoogleScholarGoogle Scholar | Chao A., and Huggins R. M. (2005). Classical closed population models. In ‘The Handbook of Capture Recapture Methods’. (Eds B. Manly, T. McDonald and S. Amstrup.) pp. 22–35. (Princeton University Press: Princeton, NJ.)

Choquenot D., Bolton N., and Woods D. (2000). Evaluating the application of aerial survey to estimate Himalayan thar densities. Landcare Research Contract Report: LC0001/29. Landcare Research, Wellington.

Freeman M. (2005). Density estimation of feral horses in Guy Fawkes River National Park New South Wales, using an aerial mark–recapture method. B.Nat.Res. Thesis, University of New England, Armidale.

Garrott, R. A. , Siniff, D. B. , and Eberhardt, L. L. (1991). Growth rate of feral horse populations. Journal of Wildlife Management 55, 641–648.
| Crossref | GoogleScholarGoogle Scholar | Krebs C. (1999). ‘Ecological Methodology.’ (Benjamin/Cummings: San Francisco, CA.)

Laake, J. , Dawson, M. J. , and Hone, J. (2008). Visibility bias: mark–recapture, line-transect or both? Wildlife Research 35, 299–309.
| Crossref | GoogleScholarGoogle Scholar | Ransom J., Singer F. J., and Zeigenfuss L. (2005). Annual report for 2004 wild horse research and field activities. Open-File Report 2005–1316. US Geological Survey, Fort Collins, CO.

Turner, J. W. J. , Wolfe, M. L. , and Kirkpatrick, J. F. (1992). Seasonal mountain lion predation on a feral horse population. Canadian Journal of Zoology 70, 929–934.
Walter M. J. (2002). Population ecology of wild horses in the Australian Alps. Ph.D. Thesis, University of Canberra.

Walter, M. , and Hone, J. (2003). A comparison of 3 aerial survey techniques to estimate wild horse abundance in the Australian Alps. Wildlife Society Bulletin 31, 1138–1149.


White, G. C. , and Burnham, K. P. (1999). Program MARK: survival estimation from populations of marked animals. Bird Study 46, 120–139.


Wilson, B. , Hammond, P. S. , and Thompson, P. M. (1999). Estimating size and assessing trends in a coastal bottlenose dolphin population. Ecological Applications 9, 288–300.
| Crossref | GoogleScholarGoogle Scholar |




* MJD previously published as M. J. Walter.