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Published (Version of Record)CC BY-NC-ND V4.0, Open Access
Journal article
Effectiveness and costs of helicopter-based shooting of deer
Wildlife Research, Vol.50(8-9), pp.617-631
2023
Abstract
Context.
Helicopter-based shooting has been widely used to harvest deer or control overabundant populations in Australasia, but the effectiveness and cost of this method as a deer control tool has seldom been evaluated.
Aims.
We evaluated the effectiveness and costs of helicopter-based shooting of fallow deer (Dama dama) and chital deer (Axis axis) in eastern Australia by quantifying (1) reductions in density, (2) the relationship between numbers killed per hour and deer density (i.e. the functional response), (3) the costs of control and (4) the effort-outcome and cost-outcome relationships.
Methods.
We evaluated the costs and effectiveness of 12 aerial shooting operations aiming to reduce fallow deer (n = 8) or chital deer (n = 4) population densities at nine sites in eastern Australia. Sites were characterised by fragmented woodland, and all but one operation aimed to reduce grazing competition with livestock. We used precontrol population density estimates and operational monitoring data to estimate the costs and outcomes of each operation. We combined data from all operations to estimate the relationship between shooting effort and population reduction, as well as costs associated with different levels of effort.
Key results.
Population reductions for operations ranged from 5% to 75% for fallow deer, and from 48% to 88% for chital deer. The greatest population reductions occurred when effort per unit area was greatest, and the largest reductions in deer density occurred when shooting was conducted in consecutive years. The functional response of hourly kills to deer density was best described by a modified Ivlev model, with the asymptotic kill rate estimated to be 50 deer per hour. There was no support for the existence of a prey refuge, that is, a threshold population density below which no deer could be shot. Helicopter charter was the primary cost of helicopter-based shooting programs, followed by labour; firearm and ammunition costs were relatively minor.
Conclusions.
Helicopter-based shooting can rapidly reduce deer populations over large geographic areas, but the magnitude of the reduction depends on the effort (hours of shooting) per deer per km(2).
Implications.
Aerial shooting operations should include a pre-control population survey so that (1) measurable objectives can be established, (2) the likely level of effort and cost required for objectives to be met can be estimated and planned for, and (3) the realised population reduction can be estimated.
Details
- Title
- Effectiveness and costs of helicopter-based shooting of deer
- Authors/Creators
- Andrew J. Bengsen - New South Wales Department of Primary IndustriesDavid M. Forsyth - New South Wales Department of Primary IndustriesAnthony Pople - Department of Primary IndustriesMichael Brennan - Department of Primary IndustriesMatt Amos - Department of Primary IndustriesMal Leeson - Local Land Services Regional Operations, 112 Market Street, Mudgee, NSW 2850, Australia.Tarnya E. Cox - New South Wales Department of Primary IndustriesBec Gray - New South Wales Department of Primary IndustriesOllie Orgill - Australian GovernmentJordan O. Hampton - Reef EcologicTroy Crittle - New South Wales Department of Primary IndustriesKym Haebich - Limestone Coast Landscape Board, 61 Anzac Terrace, Keith, SA 5267, Australia.
- Publication Details
- Wildlife Research, Vol.50(8-9), pp.617-631
- Publisher
- CSIRO Publishing
- Number of pages
- 15
- Grant note
- NSW Department of Primary Industries (Biosecurity and Food Safety and the Special Purpose Pest Management Rate) PO1-L-001 / Centre for Invasive Species Solutions project `Cost-effective management of wild deer' Biosecurity Queensland and Central Tablelands Local Land Services NQ Dry Tropics SA Department for Environment and Water's Aerial Marksman Team
- Identifiers
- 991005579934407891
- Copyright
- © 2023 The Author(s) (or their employer(s)).
- Murdoch Affiliation
- Centre for Terrestrial Ecosystem Science and Sustainability
- Language
- English
- Resource Type
- Journal article
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