13th Australasian Vertebrate Pest Conference Proceedings Keven Drew Te Papa Wellington, New Zealand 2-6 May 2005 Hosted by Manaaki Whenua Landcare Research PO Box 69, Lincoln 8152, New Zealand. www.landcareresearch.co.nz
39 FACILITATING THE MANAGEMENT OF FOXES ON PRIVATE LAND: ARE LANDHOLDERS INTERESTED? Jason Riethmuller 1, Steve McPhee 2,3, Scott McLean 1, Dave Ritchie 1, John Matthews 1, Dave Blackie 1, Ian Brown 1 and Gary Box 1. 1 Department of Primary Industries, Victoria. jason.riethmuller@dpi.vic.gov.au 2 Primary Industries Research Victoria, 621 Sneydes Rd., Werribee, 3030 3 Agricultural Technical Services P/L, 177 Ballan Rd., Werribee, 3030 ABSTRACT: Coordinated ground baiting programs to reduce fox predation of lambs were implemented in sheep producing areas of Victoria. Baiting occurred in autumn and spring 2004 with a third program scheduled for autumn 2005. The number of landholders participating, area baited and bait density were monitored over seven, 307-703km 2 areas. Estimates of fox density were determined over 79-105km spotlight transects before and after baiting. For the autumn baiting period the number of landholders participating was low (5-26%), the proportions of areas baited were low (3-36%) and the density of baits too low (0.7-4.1 baits/km 2 ) to cause major populations declines in monitored areas. However, baits/area baited may have been sufficient (3-53 baits/km 2 ) to causes short-term population declines at a property level. During spring very few landholders participated in the baiting program. Commencing with an estimated mean density of 0.82 (range 0.48-1.18) foxes/km 2, fox numbers declined after autumn baiting (52%). They remained static prior to spring baiting (51%), declined slightly after spring baiting (38%) and returned to original level (104%) prior to autumn 2005 baiting. The decline in fox numbers resulting from facilitated baiting would not be expected to have a major impact on the fox populations with in the monitored areas. INTRODUCTION Nationally the annual cost of fox predation on lambs is estimated at around $40 million, assuming foxes take 5% of all viable lambs Australia wide. Governments are estimated to spend around $2 million on fox control annually and landholders probably spend around $5 million (Bomford and Hart 2002). Coordinated, community-based fox baiting programs integrated with other control measures are considered to be an efficient means to manage foxes. A three-year Victorian government Enhanced Fox Management Program (EFMP) was introduced in 2002 aimed at minimising the impacts of foxes on agricultural and biodiversity assets. The first phase of this initiative consisted of a trial, where a $10 bounty was paid on each fox tail presented to a collection point. An evaluation of this trial in mid-2003 found that it had failed to reduce fox numbers to a point where a long-term reduction in fox impact could be expected (VIAS 2003). In response to this, it was decided that the remaining two years of the EFMP would be on an integrated approach to fox control, underpinned by community-based, coordinated baiting programs, with a particular emphasis on the protection of the prime lamb and wool industries. The aim was to motivate the farming community to manage foxes on private land in a more coordinated, long-term and strategic manner through targeted extension activities. Monitoring programs were implemented to determine the efficacy of these community-based fox control programs and to provide information to landholders to improve the management of foxes.
40 METHODS Monitor sites Seven priority areas (307-703km 2 ) were selected from Australian Bureau Statistics data that defined areas of high value prime lamb and wool production. Two coordinated baiting programs occurred over 4-10 week intervals in autumn and spring 2004. A third baiting program is scheduled for autumn 2005. Landholder participation, area baited and bait density were monitored. Facilitation effort Traditional extension methods such as media releases, newsletters, field days and phone or personal contacts were used to promote the program. Department staff facilitated the effort and issued fox baits from field sites to aid in landholder access to baits. Monitoring change in fox abundance Spotlight fox counts commenced soon after sunset on three occasions before and after coordinated baiting programs were implemented. Counts occurred, where possible, on consecutive nights, along secondary roads (79-105km) from the tray of slow moving utility using a 100w spotlight. Transects where mapped and surveyed to determine area viewed by spotlight and data are presented in foxes/km 2 of area seen. RESULTS Landholder participation For the autumn 2004 baiting period the numbers of landholders participating in the baiting programs were low, the proportions of areas baited were low and the density of baits most likely too low to cause major populations declines in monitored areas (Table 1). However, at most sites, baits/area baited may have been sufficient (3-53 baits/km 2 ) to causes short-term population declines at a property level. During spring baiting period, no landholders baited at Edenhope, Yarram and Euroa. At the remaining sites the participation of landholders was poor (Table 1). Table 1. Landholder participation, proportion of area baited for the autumn and spring baiting 2004 and baits/km 2 for the autumn 2004 baiting period. Skipton Hamilton Edenhope Yarram Euroa Underbool Woosang No. of landholders 114 280 60 170 132 35 66 Autumn 2004 23% 13% 25% 8% 5% 23% 26% Spring 2004 4% 2% - - - 7% 9% Total area (km 2 ) 523 703 489 489 307 639 419 Autumn 2004 36% 30% 16% 11% 3% 12% 27% Spring 2004 4% 14% - - - 5% 17% Autumn 2004, baits/km 2 for the target areas and areas baited Target area 2.8 4.1 0.8 1.6 1.5 0.7 3.5 Baited area 7.7 13.7 5.0 14.8 52.7 3.1 13.2
41 Change in fox abundance Commencing with an estimated mean density of 0.82 (range 0.48-1.18) foxes/km 2, mean numbers of foxes/km 2 declined after autumn 2004 baiting (0.47, range 0.17-0.72). Fox numbers remained static prior to spring 2004 baiting (0.44, range 0.15-0.88), declined slightly after spring baiting (0.34, range 0.10-0.62) and returned to original level (0.89, range 0.20-1.66) prior to autumn 2005 baiting (Fig. 1). Edenhope Euroa 200% Hamilton Skipton 150% Foxes per sq km prior to Autumn 2004 baiting Woosang Yarrum Underbool Mean % of foxes 100% 50% 1.18 1.03 0.82 0.62 1.09 0.89 0.75 0.48 52% 51% % of pre-autumn density estimates 38% 104% 0% (a) Pre -autumn (b) Post-autumn (b) Pre-spring (b) Post-spring (a) Pre -autumn baiting 2005 Fig. 1 Foxes/km 2 at the commencement of the program and foxes remaining expressed as a proportion of the pre-autumn 2004 fox densities for estimates taken before and after seasonal baiting programs (a b, P<0.05, t-test with equal variances) DISCUSSION Studies from Australia and overseas demonstrate that for both low and high fox densities, lethal baiting provides the most effective and efficient means of fox control when integrated with other control methods (Saunders and McLeod, in press). In August 2003 the bounty trial was replaced with targeted and coordinated fox control programs, primarily based on coordinated baiting programs but integrating all existing control options. Departmental staff proactively facilitated fox control efforts in local areas using a range of traditional extension methods, to provide landholders with the necessary advice and assistance to enable well planned fox control programs to be organised. Monitoring of landholder participation and fox abundance resulting from the autumn and spring baiting programs showed landholder participation in baiting programs was too low to achieve effective management of foxes within the monitored areas (Table 1 and Fig. 1). For all sites combined, the participation by landholders for the respective autumn and spring baiting were low (18% and 3%) and the portions of the target areas baited were also low (19% and 6%). This is in accord with a survey carried out before the coordinated baiting programs commenced to provide
42 baseline information on landholder motivation, current fox control practices and perception of success for managing foxes (McGeary 2005). This survey was conducted around the four of the targeted areas and although 80% of landholders perceived foxes to be a problem, the survey found only 27% of landholders used baiting to control foxes. Of those baiting, 67% baited once a year with only 18% baiting more often. Similar baiting frequencies were observed from New South Wales surveys (Balogh 2001) where for those baiting, 90% of respondents baited no more than once per year. The baseline survey (McGeary 2005) also identified potential explanations for low participation. Landholders preferred shooting as a primary control method due a perception that shooting is a more effective control option. The most common reasons landholders no longer baited was the risk posed to working dogs and concerns related to too much red tape to obtain a license to purchase bait and a permit to obtain baits. Confidence in the effectiveness of baits was also identified as a concern. This body of work, along with the current surveys of attitude and motivation of fox management, clearly show that even when lamb prices are relatively buoyant, there are barriers for landholder involvement in coordinated broadscale baiting programs. Effective broadscale management of foxes by landholders is inadequate, for there is a apparent knowledge barrier related to a lack of understanding of fox behaviour, population dynamics, dispersal characteristics, 1080 toxicology etc. Spotlight counts of fox abundance shows fox populations within the areas they manage rebounding to original numbers within 12 months (Fig. 1). For those that do bait, the reduction of foxes at a local level may reduce lamb predation but this is difficult to quantify and there may be a perception across the broader farming community that controlling foxes to improve flock productivity may be of limited benefit. Information to address all of the potential explanations for low participation were addressed through the extension programs. Many of these barriers were recognised early and strategies were developed that aimed to address them. Despite the large amount of targeted information available from experienced Departmental staff backed by detailed research and experience from Victoria and interstate, participation rates in coordinated bating programs remain low. This problem is not unique to this program and has often beset pest animal control programs elsewhere. Extension information could be developed to better target these gaps in knowledge. But in the eastern states of Australia the efficacy of ground baiting foxes over large areas has not been extensively evaluated so it is difficult to advise landholders how to manage foxes effectively. Toxic ground baiting is dependent on factors such as: timing of baiting programs (fox/prey biology and behaviour), frequency of baiting, duration of baiting, baiting density relative to fox density, bait placement across the landscape. More applied research is require to determine optimum ground baiting practice and to evaluate the benefits of baiting at a local level compared to broadscale baiting. Further research is also required into the social drivers and barriers to landholder participation in pest animal control programs. Large bodies of evidence exist to demonstrate the effectiveness of well delivered programs, a range of tools exist for managing the impacts of many of our major pest animal species and yet challenges often still remain in getting these techniques effectively applied on the ground by land managers.
43 ACKNOWLEDGMENTS The authors gratefully acknowledged support provided by: Graham McKecknie, Stuart Lardner, Brian Howlet, Rick James, Linda Murray, Ryan Cooke, Scott Edwards, Shane O Brien, Leanne Fisher and John James. Mapping support provided by Naomie Wilson, Jenni Nunan and Greg Robertson. The Primary Industries Research Victoria, Animal Experimentation Ethics Committee approved the procedures described as protocol number 2003/05-2519. The program was funded by the Land and Catchment Division of the Victorian Department of Sustainability and Environment. REFERENCES Balogh, S.; Gentle, M.; Brown, S. 2001. Out fox the fox -Landholder surveys assiting with implementing best practice fox baiting. 12 th Australasian Vertebrate Pest Conference, p 307. Bomford, M.; Hart, Q. 2002. Non-indigenous vertebrates in Australia. Pp. 25 44 in: D. Pimental (ed), Biological Invasions: Environmental and Economic Costs of Alien Plant, Animal and Microbe Invasions. CRC Press, New York. McGeary, J. 2005. Enhanced fox management program-phase 2, Baseline survey. 13 th Australasian Vertebrate Pest Conference. (This edition) Saunders, G.; McLeod, L. in press. Fox Management strategies in Australia. Report to the BRS by Vertebrate Pest Research Unit, NSW Agriculture, Orange. VIAS 2003. Evaluation of the 2002/03 Victorian fox bounty trial, Victorian Institute of Animal Science, Vertebrate Pest Research Department, Department of Primary Industries, Victoria. ISBN 174106 646 8.