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RESEARCH ARTICLE
Contents Vol 32(8)

Increasing the efficacy of Judas goats by sterilisation and pregnancy termination

Karl J. Campbell A B C H , Greg S. Baxter A , Peter J. Murray D , Bruce E. Coblentz E , C. Josh Donlan F G and Victor Carrion G. C
+ Author Affiliations
- Author Affiliations

A School of Natural and Rural Systems Management, University of Queensland Gatton, Gatton, Qld 4343, Australia.

B Charles Darwin Foundation, Casilla 17-01-3891, Quito, Ecuador.

C Galápagos National Park Service, Puerto Ayora, Isla Santa Cruz, Galápagos, Ecuador.

D School of Animal Studies, University of Queensland Gatton, Gatton, Qld 4343, Australia.

E Department of Fisheries and Wildlife, Nash Hall 104, Oregon State University, Corvallis, OR 97331-3803, USA.

F Department of Ecology and Evolutionary Biology, Corson Hall, Cornell University, Ithaca, NY 14853-2701, USA.

G Island Conservation, Center for Ocean Health, 100 Shaffer Road, Santa Cruz, CA 95060, USA.

H Corresponding author. Email: karl@fcdarwin.org.ec

Wildlife Research 32(8) 737-743 https://doi.org/10.1071/WR05033
Submitted: 22 March 2005  Accepted: 18 October 2005   Published: 20 December 2005

Abstract

The use of Judas goats to locate remnant animals is a potentially powerful tool for enhancing goat-eradication efforts, which are especially important to island conservation. However, current Judas goat methodology falls short of its potential efficacy. Female Judas goats are often pregnant at the time of deployment or become impregnated in the field; pregnant females leave associated goats to give birth, causing downtime of Judas goat operations. Further, male Judas goats may inseminate remnant females. Sterilising Judas goats prior to deployment removes these inefficiencies. Here, we describe two methods (epididymectomy for males and tubal occlusion for females) that sterilise Judas goats while still maintaining sexual motivation and other behaviours associated with intact animals. These surgeries are straightforward, time efficient, and may be conducted in the field by staff with minimal training. Given the widespread and deleterious impacts of non-native herbivores to ecosystems and the importance of Judas operations in detecting animals at low densities, sterilisation and termination of pregnancy should be applied routinely in Judas goat (and possibly other species) programs to increase the efficacy of low-density control operations and eradication campaigns.


Acknowledgments

Felipe Cruz provided encouragement and direction throughout. C. Lavoie managed Santiago JG data, while Project Isabela hunters collected field data. Veterinarians J. Flanagan, D. Forrest, J. Foxworth, D. Kraemer, J. McCosker and J. Romano provided advice on selection of appropriate methods and their application. B. Hampson provided logistical assistance and valuable advice. A. Lisle assisted with experimental design. F. Cruz and J. Flanagan provided comments on a draft manuscript. This project was conducted under the University of Queensland’s Animal Ethics Committee Approval #NRSM/388/00/UQ/CDF/GNPS and NRSM/416/04/CDF/PhD in partial fulfilment of a postgraduate degree (to KJC). Field work was conducted as part of the management activities of the Galápagos National Park Service (GNPS) and the Charles Darwin Foundation for the Galápagos Islands (CDF), to whom we owe thanks. Funding was provided by the CDF, Charles Darwin Foundation Inc., Europe-based Friends of Galápagos Organisations, the GNPS, Lindblad Expeditions, and the University of Queensland. TAME airlines provided reduced fares. Additionally, this work was accomplished with the support of Project ECU/00/G31 ‘Control of Invasive Species in the Galápagos Archipelago’, a donation from the Global Environment Facility (GEF) to the Ecuadorian Government, represented by the Ministry of Environment. Project ECU/00/G31 is implemented by the United Nations Development Program (UNDP) and is executed by the Galápagos National Park Service, Charles Darwin Foundation, National Institute for Galápagos (INGALA) and Ecuadorian Service for Agriculture and Livestock Sanitation – Galápagos (SESA-Galápagos). Additional support was provided by Cornell University (to CJD). Opinions expressed herein belong to the authors and do not necessarily reflect the opinions of GEF/UNDP. This is CDF contribution No. 1017 to conservation of the Galápagos Islands.


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