An increase in mesopredators caused by the removal of top-order predators can have significant implications for threatened wildlife. Recent evidence suggests that Australia’s top-order predator, the dingo, may suppress the introduced cat and red fox. We tested this relationship by reintroducing 7 foxes and 6 feral cats into a 37 km2 fenced paddock in arid South Australia inhabited by a male and female dingo. GPS datalogger collars recorded locations of all experimental animals every 2 hours. Interactions between species, mortality rates, and postmortems were used to determine the mechanisms of any suppression. Dingoes killed all 7 foxes within 17 days of their introduction and no pre-death interactions were recorded. All 6 feral cats died between 20 and 103 days after release and dingoes were implicated in the deaths of at least 3 cats. Dingoes typically stayed with fox and cat carcasses for several hours after death and/or returned several times in ensuing days. There was no evidence of intraguild predation, interference competition was the dominant mechanism of suppression. Our results support anecdotal evidence that dingoes may suppress exotic mesopredators, particularly foxes. We outline further research required to determine if this suppression translates into a net benefit for threatened prey species.
Introduced feral cats (
Interspecific killing between carnivores is common [
Where predation efficiency or prey specificity of smaller predators is superior or different to that of the top-order predator then changes in prey abundance can result [
Unfortunately little empirical data exist to support the perceived role of the dingo in suppressing fox and cat abundance at landscape scales [
Dingoes are currently excluded or controlled over most of the Australian pastoral zone for the protection of commercial stock. Understanding any role that dingoes play in controlling introduced predators could assist in seeking a balance between the control of dingoes for pastoral production and the protection of dingoes for broader biodiversity benefits.
This study aimed to test the hypothesis that dingoes can suppress feral cats and foxes by examining their interactions within a landscape scale enclosure. A pair of dingoes was reintroduced to a 37 square km fenced paddock in northern South Australia. Feral cats and foxes were reintroduced 4 months later, and all animals were monitored for up to 12 months using GPS datalogger collars. Interactions between species, mortality rates, and postmortems were used to determine if suppression was due to interference or exploitative competition and/or intraguild predation. Cats, and foxes were also introduced to an adjacent unfenced control area where dingoes were removed. Indices of cat, fox, and rabbit spoor were compared between the two areas. Two factors were critical to the study: firstly, that densities of dingoes, cats, foxes, and prey species were typical of those found in the wider environment, and secondly that all study animals were local inhabitants and familiar with the habitats present in the study area.
A 37 km2 “Dingo Paddock” was fenced between July and November 2008 (30.27°S, 136.93°E) on Stuart Creek Pastoral Station. The paddock is situated approximately 35 km north of Roxby Downs in northern South Australia and is enclosed on three sides by a 1.6 m high netting fence (50 mm holes) with a 50 cm floppy top curving inwards to keep dingoes, cats, and foxes within the paddock but allowing cats and foxes to climb in. The netting fence was based on the Arid Recovery fence design [
The southern section of the Dingo Paddock comprised a clay interdunal swale more than 2 km wide and vegetated with chenopod shrubs, bladder saltbush (
We chose an unfenced control area south of the dingo fence, a man-made wire netting fence erected to exclude dingoes from southern sheep grazing areas. The control area was on adjoining Mulgaria Pastoral Station and situated 5 km east of the Dingo Paddock, a distance considered sufficient to ensure independence but close enough to contain similar habitat types and reflect similar climatic events. Habitats within the control area were similar to the Dingo Paddock with a large clay swale, an area of closely spaced sand dunes, a pastoral dam, and an area of breakaways. The dam within the control area was stocked with domestic cattle (
The Roxby Downs’ climate is arid, failing to reach its long-term average rainfall of 166 mm in 60% of years [
Rainfall recorded 6 months prior and during the study period. The line indicates the monthly average.
In December 2008, a male and female dingo were captured from Stuart Creek Pastoral Station and released into the paddock. The wild dingoes were captured using soft catch Jake foot hold traps set around a cattle carcass located approximately 50 km north of the dingo paddock. Traps were fitted with springs to reduce injury and were checked in the late evening and again at dawn. No teeth damage was recorded after capture. We lightly anaesthetised the captured adult dingoes using a mixture of 1 mL of Medetomidine Hydrochloride and 0.5 mL of Ketamine, administered intramuscularly.
The anaesthetic was reversed using 0.5 mL of Atipamezole Hydrochloride. Anaesthetic and reversal doses for all animals were prepared in advance by a qualified veterinarian who also trained all animal handlers in correct administration of the preprepared doses. An anaesthesia procedure was developed and approved by the Wildlife Ethics Committee, including monitoring of rectal temperature during anaesthesia. Dingoes were weighed, checked for reproductive condition, and fitted with Global Positioning System (GPS) datalogger ARGOS satellite collars with VHF (SIRTRACK, Havelock, New Zealand) that nominally recorded fixes every 2 hours. Collars weighed 640 g and were no more than 4% of dingo body weight, less than the manufacturer’s, and South Australian Wildlife Ethics Committee’s maximum approved proportional collar weight of 5%. Dingoes were transported in an air-conditioned car and released at the dam within the dingo paddock on the same morning as capture. Dingoes were checked after two hours and were then radiotracked daily for the first week. Radiotracking fixes indicated that both dingoes began moving throughout the paddock within a few hours of release. Although the number of dingoes placed in the paddock mirrored regional density, we provided a food subsidy to determine whether the availability of prey was limited in the paddock and could have influenced study outcomes. Between December 2008 and October 2009, kangaroo or rabbit carcasses and occasionally meat offcuts were placed at least fortnightly at a carcass dump established near the dam within the dingo paddock. Two remote motion sensor cameras (DVR Eye, Pix Controller, PA, USA) were placed at the carcass dump to record activity.
Weekly ARGOS satellite downloads were used to check whether the dingoes were in the paddock, and we conducted daily fence checks during the first month to repair any attempts to dig out under the fence. We recaptured the male and female dingoes in January and March 2010, respectively, to replace the GPS collars before the VHF batteries expired. No collar-related injuries such as rubbing or ulcerations were recorded. The male was captured using a single soft catch Jake trap set under an
Feral cats that remained in the paddock after construction were trapped in August 2008 and fitted with GPS data logger radiocollars with VHF (SIRTRACK, Havelock North, New Zealand) for a separate study comparing cat behaviour before and after dingo reintroduction. Cats were fitted with a small hind foot ring made from a cable tie with a 10 cm length of light chain attached. The chain dragged behind the cat when it moved and left a small indentation in soft substrate where tracks could be detected indicating that the cat had been fitted with a radiocollar. All cat tracks recorded during quad bike traverses of the paddock immediately after trapping were from collared cats suggesting that most, if not all, cats within the paddock had been captured and radiocollared. Only two of these cats still remained alive when additional cats and foxes were placed in the paddock in April 2009 and by then foot rings had been removed.
Between April and October 2009, 4 to 10 months after the dingoes were released into the paddock, we captured six feral cats and seven foxes, fitted them with radiocollars, and released them inside the dingo paddock. The majority of these cats and foxes were captured outside the paddock within 10 km of the dingo paddock in similar habitat (Table
Details, location, and fate of cats and foxes captured and radiocollared during the experiment. Distance refers to how far away from the release area the animal was initially captured. Time of death is the time interval between the first GPS fix recorded at the death location and the last fix recorded at a different location prior to death.
Animal | Distance from paddock | Release location | Sex | Release Wt | Release date | Death date | Days alive | Time of death | Habitat of death location | Cause of death |
---|---|---|---|---|---|---|---|---|---|---|
Fox 31 | 5 km | Paddock | M | 3500 | 1/6/09 | 4/6/09 | 3 | 04:56–20:56 | Swale | Dingo |
Fox 32 | 5 km | Paddock | M | 4500 | 9/6/09 | 13/6/09–14/6/09 | 5 | 08:30–08:30 | Dune | Dingo |
Fox 33 | In paddock | Paddock | F | 3500 | 24/6/09 | 24/6/09–25/6/09 | 1 | 23.03–01.02 | Dune | Dingo |
Fox 34 | 5 km | Paddock | M | 3500 | 27/6/09 | 12/7/09–13/7/09 | 17 | 22:31–00:31 | Swale | Dingo |
Fox 35 | 50 km | Paddock | F | 5005 | 15/8/09 | 20/8/09 | 6 | 23:04–03:05 | Swale | Dingo |
Fox 36 | 50 km | Paddock | F | 4400 | 18/10/09 | 28/10/09 | 10 | 22:54–02:54 | Dune | Dingo |
Fox 37 | 50 km | Paddock | F | 5200 | 16/10/09 | 18/10/09–9/10/09 | 3 | 08:30–08:30 | Dune | Dingo |
Cat 22b | In paddock | Paddock | M | 4050 | 26/4/09 | 14/6/09–13/7/09 | 48–78 | unknown | Swale | Dingo |
Cat 23b | 7 km | Paddock | F | 2950 | 22/7/09 | 2/11/09 | 103 | 20:54–22:54 | Swale | Unknown |
Cat 24b | 10 km | Paddock | F | 3750 | 28/8/09 | 30/11/09–7/12/09 | 94–112 | unknown | Swale | Unknown |
Cat 25b | 10 km | Paddock | F | 4050 | 16/9/09 | 6/10/09 | 20 | 8.59–10.58 | Creekline | Dingo |
Cat 28 | 10 km | Paddock | F | 2950 | 3/4/09 | 30/4/09 | 27 | 16:56–18:56 | Dune | Dingo |
Cat 29 | 10 km | Paddock | F | 2750 | 26/4/09 | 30/5/09 | 34 | 19:19–07:18 | Dune | Unknown |
Cat 21 | In paddock | Paddock | F | 2700 | 20/8/08 | 21/6/2009 | 300 | 17:04–19:04 | Dune | Dingo |
Cat 23 | In paddock | Paddock | M | 4200 | 28/8/08 | 8/4/09 | 210 | 17:00–19:00 | Dune | Dingo |
Fox 38 | 50 km | Control | F | 4400 | 18/10/09 | Fate unknown | ||||
Fox 39 | 50 km | Control | M | 4800 | 18/10/09 | Fate unknown | ||||
Fox 30 | 10 km | Control | M | 4000 | 14/12/09 | Fate unknown | ||||
Cat 27b | 15 km | Control | M | 4650 | 3/10/09 | Fate unknown | ||||
Cat 28b | 15 km | Control | F | 3950 | 31/10/09 | Fate unknown | ||||
Cat 26 | In control | Control | M | 3600 | 29/9/08 | 2/7/09 | 276 | Euthanased |
We weighed and sexed the cats and foxes and noted the condition of their teeth, body, and reproductive organs. Only animals weighing at least 2.7 kg were used in the study to ensure radiocollars remained less than 5% of body weight (Table
Between September and December 2009, we captured and radiocollared an additional three foxes and three feral cats and released them into the unfenced Mulgaria control area to act as controls. One control cat was trapped in the Mulgaria control area, and the other two control cats were captured within 15 km of the control area. All control foxes were captured on Roxby Downs Station, 50 km south of the dingo paddock, two in October 2009, and one in December 2009.
Between April and December 2009, we radiotracked all collared animals within the dingo paddock and control area weekly or fortnightly on foot, quadbike, or from a Cessna 172 aeroplane with a wing-mounted aerial. If an animal was found dead, its location was recorded and a thorough search of the death location ensued. Habitat, tracks, scats, bones, fur, warrens, or any other signs of interest were recorded. Any fresh carcasses were sent to Zoos South Australia where postmortems were performed by qualified veterinarians.
We converted collar downloads from Greenwich Mean Time to Australian Central Standard Time (nondaylight saving) and plotted them using Arc GIS software. Collar accuracy varied according to the number of satellites available at the time of the GPS fix, but precision was usually less than 10 m. For deceased animals, GPS fix locations were used to confirm the point of death by identifying clusters of points in the same location indicating no movement for an extended period. The time of death was estimated as the time interval between the first GPS fix at the death location and the time of the last GPS fix recorded in an area prior to the death location, which typically permitted time of death to be estimated to be within 2 hrs. In cases where multiple clusters of fixes were evident at a number of localities within a 1.5 km radius, ground searches revealed that carcasses had been dragged after death, and the first cluster was identified as the kill site. Time and location of death of all cats and foxes within the paddock were compared to dingo GPS fix locations for the same period to determine whether the dingoes were present at the death location within the correct time interval. Other factors were also considered when determining the cause of death, including the results of any autopsy and presence of dingo tracks.
The distances between all fox and dingo GPS fix locations at each 2 hr interval was used to determine if any possible encounters had occurred between the two species prior to death. Given that the approximate dimensions of the paddock were 7 km by 5 km, distances of less than 500 m between animals within a 4 hr time interval were conservatively considered possible encounters. Additionally, all GPS fix locations within 24 hrs of death were closely compared to dingo locations to determine if the dingoes had followed the foxes prior to death. GPS fix locations of cats and dingoes were also compared but only for the 24 hr period prior to death as cats remained alive longer than foxes and produced significantly more GPS fix locations for analysis.
To investigate the influence of fox presence on dingo activity, each dingo’s minimum daily distance moved was compared on days when foxes were present and absent in the paddock. Minimum daily distance was calculated as the total distance between successive GPS fix locations over a 24 hr period. At least one fox was in the paddock over three different periods between June and October for 34, 6, and 13 consecutive days, respectively. Minimum daily distances during these times were compared with the remaining 161 days when foxes were absent during the study period. Male and female dingoes were analysed separately using one-way ANOVAs.
Red kangaroos (
Indices of dingo, fox, cat, and rabbit activity were derived from the presence of spoor along 200 m track transects established in both the control and dingo paddock in the three main habitat types: sanddune, swale, and creekline. Swale transects were all placed on roads where suitable substrate for tracking existed. Transects were swept clean using a metal bar dragged behind a quadbike the night before the first of two consecutive mornings of track counts. Data from the two mornings were combined to give a presence/absence score for each transect for each monitoring period. A total of 39 transects (20 sand dune, 10 creeklines, and 9 swale) were established in the dingo paddock and 38 (20 dune, 8 creekline, and 10 swale) in the control area. All transects were sampled every 4 months from February 2008 until February 2010. Sampling began 11 months prior to dingo reintroduction and continued for 3 months after the completion of the experiment.
All seven foxes released into the dingo paddock died within 17 days of release (Table
Details of animal deaths attributed to dingoes during the experiment. Evidence for dingo attack in bold. M: Male, F: Female.
Animal | Dingo distance (m) from fox/cat during death period | At carcass hours after death | Distance from closest dingo at fix preceding kill | Both dingoes together prior to kill | Dingo tracks at death site | Carcass dragged | Saliva on carcass | Autopsy confirmed dingo attack | Fox/cat movement in 2 hours prior to death (m) | |
Male | Female | |||||||||
Fox 31 | 1200 | 2–14, 22–24, 64, 96–98, 122–130 (M) | 2014 | Yes | n/a | 100 | ||||
Fox 32 | 470,680 | 48 (M) | Yes | |||||||
Fox 33 | 900 den | 4.5–6.5 (F) | 3000 | No | n/a | 218,230 | ||||
Fox 34 | 2–161 (MF) | 2124 | Yes | n/a | 843 | |||||
Fox 35 | 20–22 (MF) | 1703 | Yes | n/a | 2833 | |||||
Fox 36 | 21 (F) | 1668 | Yes | 1662 | ||||||
Fox 37 | 1 | Yes | ||||||||
Cat 21 | 3446 den | 2,12,14,16 (F) | 1885 | No | n/a | 574 | ||||
Cat 22b | 4878 den | 2–6 (F) | 2300 | No | n/a | |||||
Cat 23 | 26 (M) | 800 | Yes | n/a | 270,670 | |||||
Cat 25b | 200 | 130 | 3–5 (M) 14–18 (F) | 1726 | Yes | n/a | 1609 | |||
Cat 28 | 300 | 160 | 2-4,12,24 1(M) 2–4 (F) | 1886 | Yes | 949 |
1Body removed within 12–24 hours of death.
2Female collar failed to record 5 fixes during death period.
Location of animal deaths attributed to dingoes within the Dingo Pen. Habitat types, rabbit warrens, and the dingo den site are also marked.
Three of the seven foxes (Fox 32, 36, and 37) were found within a few hours of death and could be necropsied (Table
Tracks and GPS fix locations from the dingoes and foxes suggested that they also killed three other foxes (Table
There were no recorded interactions between the foxes and dingoes prior to fox deaths. The only instance when dingo and fox fixes were recorded within 500 m of each other within a 4 h time interval was at the time of fox deaths. Furthermore, outside this 4 hr window, more than 450 m and 12 h were recorded between any fox and dingo locations suggesting that the first physical encounter between dingo and fox was also the last. There was also no indication that dingoes were following foxes prior to death as both species were moving in different directions, and the distance between fox and dingo GPS fix locations recorded just prior to death was between 1703 and 3000 m (Table
There was a strong trend towards longer daily movements in male and female dingoes when foxes were present in the paddock compared with when foxes were absent (female
All six feral cats released into the paddock died between 20 and 123 days after being translocated into the paddock, and we recorded evidence that at least three cats were killed by dingoes. An additional two cats already present and radiocollared in the paddock when the experiment began also appeared to have been killed by dingoes. Where dingoes were implicated in deaths, three occurred in the early evening and one in the mid morning. When the female dingo killed two cats on her own, the male dingo was at the den site, more than 1 km from the death points. Deaths occurred before, during, and after denning and were in different habitat types and locations around the paddock (Figure
A postmortem confirmed death by dingo attack in one cat (cat 28, Table
The cause of death could not be determined for three of the cats (Table
Collars were removed from dead cats and foxes, and no rubbing or collar-induced injuries were detected. The dingoes were recaptured 12–18 months after initial capture, and no collar injuries were detected.
Only one cat and no foxes could be relocated after release into the control area. The cat that was captured within the Mulgaria control area remained in the control area for 276 days before it was recaptured and euthanased at the end of the experiment. This cat sheltered extensively in rabbit warrens on rocky swales, and, although usually staying within a 12 km linear area, it was known to travel more than 35 km to the south and back again within a two week-period. This cat was recaptured three times over the study and, its weight remained between 3350 and 3600 g.
All other control animals were transferred to the control area from surrounding areas, and, despite more than five attempts to locate them using a light aircraft, they could not be found. Searches from the air included a 20 km radius around the control site, all of the original capture locations and 1 km traverses across the control area. The fate of these animals remains unknown, but it is likely that they moved away from the control area.
Prior to and during fence construction, tracks, sightings, and scats of wild dingoes, feral cats, and foxes were all observed within the dingo paddock area. However, spoor counts and spotlighting transects indicated that there were no foxes or dingoes present in the paddock when the fence was completed. Subsequent spoor counts and remote cameras detected two uncollared foxes and two uncollared cats that had climbed into the paddock at different times during the experiment.
Both control and dingo paddock transects exhibited similar trends of cat activity during the initial stages of the project (Figure
The percentage of transects (Dingo Pen
Fox spoor was recorded in the paddock when foxes were released in June but declined to zero by the end of the experiment. Fox activity in the control area was variable over the study period (Figure
The percentage of transects (Dingo Pen
The percentage of transects (Dingo Pen
Many previous studies have suggested that dingoes suppress fox abundance [
The primary mechanism for suppression of cats and foxes by dingoes in this study appeared to be direct physical attack rather than suppression of breeding or exclusion from resource points as has been suggested elsewhere [
Although cats were subjected to direct dingo attack, other forms of suppression may also have been occurring in the paddock. Burrows et al. [
Fox and cat deaths occurred at times when they were most active, foxes at night time and cats mainly at dusk. This is consistent with dingoes killing cats and foxes when they encounter them rather than digging them out of warrens or using olfactory cues to seek them out. Corroborating this assumption was the independent movement patterns of dingoes, cats, and foxes in the 24 hrs prior to death and deaths occurring when animals unknowingly moved into the path of the dingoes or vice versa. Therefore, it is likely that dingoes killed cats and foxes on an opportunistic basis, but they were probably aware of the foxes in the paddock and may have increased their daily movements to increase the chances of encountering them.
Containing all three animal species within a paddock, albeit a landscape scale one, may have influenced the outcomes of the study by restricting the movement of some cats and foxes and perhaps rendering them more likely to encounter or be cornered by a dingo. The home range of cats and foxes vary considerably in the arid zone with averages of between 20 and 30 km2 commonly recorded [
The dingoes also appeared to have behaved typically, breeding in April/May and whelping in June, as recorded elsewhere in arid Australia [
Deaths were recorded at various times between April and October, before, during and, after the denning period. It is not known if dingoes will kill cats and foxes over the summer months. Although resident cats in the paddock when the dingoes were introduced in December were not killed until April or June, the dingo pair may have been more likely to influence other predators or competitors once they had formed a pack and started defending resources [
Several animals appeared to have been chased around bushes or over short distances prior to death. The dingoes were travelling together when nine of the 12 foxes and cats were killed. It is impossible to determine if both dingoes assisted in the kills, but it appears likely, as dingoes regularly hunt and kill prey cooperatively [
Of those cats killed by dingoes, the resident cats survived longer than the cats placed in the paddock, possibly suggesting that the resident cats were more familiar with shelter sites and able to avoid interactions with the dingoes for longer. However, three of the five cats placed in the paddock do not appear to have been killed by dingoes, and their causes of death are unknown. Feral cats in the arid zone are thought to suffer from periods of nutritional stress leading to high natural mortality of more than 50% in less than 12 months [
Results from this study need to be extrapolated cautiously. Our experiment is a single replicate. Due to logistical constraints, we could only trial one pair of dingoes in a single paddock. Ideally, the experiment should be repeated using another dingo pair, and foxes and cats added in different seasons. It is likely that interactions between cats, foxes, and dingoes will vary depending on habitat types, breeding seasons, and food availability. The relatively open habitat in the paddock, despite numerous rabbit warrens for shelter, may have made it easier for dingoes to locate and catch cats and foxes. More wooded environments or areas with denser understorey may enable cats, foxes, and dingoes to coexist more readily. Despite similar habitat types in capture and release locations, for some animals, the paddock was an unfamiliar environment and may have influenced their susceptibility to dingo attack. Track searches of the paddock in early June 2010, 6 months after the experiment finished, located very low abundance of fox and cat tracks suggesting that these species had reinvaded the paddock. It is not known if dingoes permanently suppress cats and foxes over long periods or are more tolerant of cats and foxes outside the breeding period. Finally, drought conditions may have influenced results and increased dingo attacks due to competition for food resources.
Several studies have identified a loss in species biodiversity when a keystone or “apex” mammalian predator is removed [
Secondly, like other canids, foxes and dingoes both have a predisposition to kill several prey and consume only few or none of the total kill [
Thirdly, the relationship between dingo density and the magnitude of cat and fox suppression will have a major influence on whether a net benefit to prey species is realised. If low dingo density, particularly in concert with established breeding territories [
Finally, unlike cats and foxes, dingoes are dependent upon water, at least during summer. Therefore, in desert areas dingo density and their predation and mesopredator suppression will be spatially and temporally patchy compared with cats and foxes. Many desert animals rely on restricted refugia areas for survival during drought [
Although the ecological role of the dingo requires further verification in other environments, our study supports a growing body of evidence that the dingo plays an important role in ecosystem function. Therefore, we recommend that functional dingo populations in rangeland areas are maintained at landscape scales and that dingo control for calf protection is restricted to targeted control during exceptional circumstances. Research should now focus on whether dingoes provide a net benefit to threatened wildlife species by investigating the influence of prey size and behavioural traits, surplus killing, and dingo density. We predict that smaller, solitary, and wide-ranging native species close to permanent watering points will benefit the most from mesopredator suppression. Finally, the red fox, feral cat, and dingo all have catholic diets that can change rapidly depending on resource availability. Despite the dingo arriving in Australia several thousand years ago, all three species are relatively new arrivals in Australia. Researchers should consider that the mechanisms and benefits of mesopredator suppression in Australia may not mirror those recorded in North America and Europe where mesopredators are usually native and their diets more prey specific.
This study was conducted by Arid Recovery, a joint conservation initiative between BHP Billiton, the S.A. Department for Environment and Natural Resources, The University of Adelaide and the local community. Funding was provided by the South Australian Arid Lands Natural Resource Management Board, Olympic Dam Expansion Project, and Arid Recovery. Greg Kammermann and his assistants worked tirelessly on building the dingo paddock on time and within budget. Many other volunteers and staff have contributed to this work, particularly, A. Kilpatrick, A. Clarke, T. Moyle, D. Sandow, C. McGoldrick, G. Miller, and B. Arnold. Thanks are due to M. Lloyd for providing carcasses for our carcass dump and assisting with fox captures. Rob Savage gave permission to use Mulgaria Station as a control site, and Dr D. Paton provided useful comments on the manuscript. The authors are indebted to the veterinarians from Zoos South Australia, in particular I. Smith, W. Boardman, and D. McLelland, who conducted the necropsies, provided veterinary advice, and assisted with attempting to retrieve the dingo collars. Dr A. Melville-Smith from the Roxby Downs Veterinary Clinic assisted with anaesthesia dosages and training. This study was conducted under ethics approval (permit no. 6/2007-M3) from the South Australian Wildlife Ethics Committee.