Can the Judas technique be applied to pest birds?
Andrew P. Woolnough A B , Tim J. Lowe A and Ken Rose AA Vertebrate Pest Research Section, Department of Agriculture and Food, Western Australia, 100 Bougainvillea Avenue, Forrestfield, WA 6058, Australia.
B Corresponding author. Email: awoolnough@agric.wa.gov.au
Wildlife Research 33(6) 449-455 https://doi.org/10.1071/WR06009
Submitted: 19 January 2006 Accepted: 11 August 2006 Published: 4 October 2006
Abstract
The Judas technique was evaluated for its use as a technique to assist with the control of the common starling (Sturnus vulgaris). This technique uses the natural behaviour of a gregarious animal to betray the location of itself and its companions through radio-telemetry. Two trials were conducted to assess and develop the technique for starlings. The first trial was conducted near the western edge of the starling’s current established range in Australia, at Penong in South Australia. Nine out of ten radio-tagged birds were successfully tracked from the ground and air. Estimates of the areas utilised varied from 1.1 km2 to 96.5 km2 (100% convex polygons). Night-time roosts were found for three of the nine radio-tagged birds and control (shooting) recovered just one bird directly associated with a Judas starling, as well as the radio-tagged bird. The second trial was conducted at Munglinup near Esperance in Western Australia. Munglinup is the site of a recent infestation of starlings and is the most western-known outlier of this pest in Australia. At this site, five radio-tagged starlings tracked from the ground and air, utilised areas ranging from 0.7 km2 to 51.6 km2. Reduced fidelity to roosting trees impaired our ability to destroy starlings here. However, the real value of the Munglinup trial was to expand the geographical area known to be occupied by this population from 103 km2 to more than 225 km2 and to identify habitats and roost sites used by the starlings. We conclude that the Judas technique could be applied to starlings and other pest birds with similar social structures as a means of strategic surveillance rather than as an adjunct to control per se.
Acknowledgments
This work was funded by the Western Australian Department of Agriculture and Food (DAFWA) and undertaken with the following approvals: DAFWA Animal Ethics Committee (#05-02-21 and #05-04-26), the Wildlife Ethics Committee of the South Australian Department for Environment and Heritage (DEH; #2/2003), DEH Permit to Undertake Scientific Research (#Q24460 2), and the Australian Bird and Bat Banding Scheme of the Commonwealth Department of Environment and Heritage (#1861). We are indebted to the piloting skills of Nigel Dunn and Fiona Simmonds (Whale Air, Goolwa, SA) and Stephen Maughan (The Aeroplane Co., Jandakot, WA), the field knowledge of Lynton Gurney (DAFWA, Penong trial), field assistance from Lee Ann Rollins (UNSW, Munglinup trial) and the support from the DAFWA Starling Control Team lead by Ron Payne. The paper was improved by the comments from Duncan Sutherland, Peter Thomson, Laurie Twigg, Gary Martin and Marion Massam.
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