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Pack size and prey behaviour affects prey selection and the predation of livestock by dingoes Lee Allen Peter Thomson and Alan Lisle


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Pack size and prey behaviour affects prey selection and the predation of livestock by dingoes
Lee Allen Peter Thomson and Alan Lisle


Abstract
Dingo control (1080 baiting) increased the magnitude and frequency of predation loss of calves (Bos spp.) relative to adjacent areas where dingoes were left alone (Allen & Gonzalez). We re-examined the published and unpublished data from Thomson's (1992) studies to examine the biological reason for this phenomenon. Dingo control primarily results in reduced pack size. This compromises the hunting efficiency of surviving and re-colonising dingoes. When small to medium-sized, (preferred) prey populations decline, often as a consequence of below average rainfall, dingoes switch to less profitable prey. Average group size and mean age of dingoes observed killing sheep, kangaroos and free-ranging feral cattle increase from 1.5 dingoes and 1.9 years for sheep, 3.0 dingoes and 3.3 years for kangaroos to 4.25 dingoes and 4.6 years for feral cattle. Reduced pack size and pack coordination prevent disturbed dingo populations from efficiently capturing the larger macropod prey. We conclude this is the cause why they consequently prey on domestic cattle. Domestication and the respective behaviour of sheep and cattle to the presence of dingoes are proposed as significant factors affecting the vulnerability of these two domestic species to predation. While dingoes do not prefer cattle to macropods, they are nevertheless, more efficiently killed by dingoes. The relationship between prey behaviour and profitability is discussed in relation to optimal foraging.

Keywords: Canis lupus dingo; hunting behaviour; predator control; prey selection; re-colonisation; optimal foraging; profitability; pack size; livestock predation; surplus killing.
Introduction
Wherever dingoes, Canis lupus dingo occurred in Australia their depredation on livestock led to them becoming a declared pest. Sheep producers are severely affected by dingoes. Hence, most of Australia’s sheep production is contained inside a continuous, 5342 kilometre, barrier fence. While sheep producers are unanimous in their opposition to dingoes, beef producers have contrasting perceptions of their relative impact (Breckwold 1988, Allen and Sparkes 2000; Hrdina 1997). While many beef producers regard dingoes as serious pests to calves and weaner cattle and conscientiously control dingoes, others take no action believing that dingoes control pest populations of kangaroos and wallabies (Macropodidae), rabbits (Oryctolagus cuniculus) and feral pigs (Sus scrofa).
Throughout Australia the government agencies responsible for pest animal control facilitate the use of fluoroacetate (Compound 1080) and coordinate, dingo baiting campaigns. Poison baits are often layed from vehicles. However, a significant proportion of dingo baiting is done from aircraft. As participation in dingo control is not compulsory, baiting campaigns are generally conducted in a piecemeal approach, property by property. Produced, is a mosaic of baited and non-baited areas.
Allen and Gonzalez (In Preparation; 1998) evaluated the role of dingo predation to the beef industry in northern and central Australia. They compared lactation failures of known-pregnant cattle (Bos indicus and Bos indicus cross) contained within large paddocks (>40 000 ha) where dingoes were left alone to cattle in similar sized paddocks on the same property, where dingoes were regularly baited. By conducting their experiments on individual properties of 800 and 9000 km2, breed, age, nutrition, disease and cattle management practices were kept similar. Under these conditions lactation failure due to normal factors like dystocia and mismothering are found to be comparable between paddocks (Unpublished Data, Geoff Fordyce, Swan's Lagoon Research Station, Department of Primary Industries). Thus, Allen and Gonzalez (In Preparation) assumed the statistical differences in calf loss between baited and non-baited paddocks in the same year were a measure of dingo predation.
Their research showed that:


  1. In many years dingo predation of calves could not be detected in either baited or non-baited areas,




  1. Predation of calves was higher and occurred more often where dingo control had occurred compared to where dingoes were not controlled, and




  1. Calf loss was negatively correlated to annual rainfall and positively correlated to when dingoes had re-colonised subsequent to baiting (Allen 2000).

This paper explores the biological reason why predator baiting, results in increased calf predation compared to calf losses in undisturbed dingo populations.


Methods
Two hundred and five dingoes were captured and radio-collared in the north west of Western Australia (see Thomson 1992 for a description of the study). The movement, behaviour and interaction of these dingoes, and their non-collared, associates were observed and recorded between 1977 and 1984. The ages of 61 dingoes, 39 that dispersed, (permanently left their former territories) and a further 22 that were destroyed in sheep country, were compared to 205 dingoes, aged when first captured (Thomson 1992). The sample of 205 dingoes had been trapped or shot in sheep and cattle country during the study.
These data were compared to front foot length measurements collected in baited and non-baited areas in north and western Queensland (Allen and Engemen 1997), In Preparation PhD Thesis). Foot size measurements were made to the nearest 0.5 cm from spoor on tracking stations. Fifty tracking stations were monitored for at least four consecutive days in each of the treatment areas. Measurements from five surveys conducted at Strathmore in the Gulf of Carpentaria and 12 surveys at Mount Owen in southwest Queensland were combined to produce a frequency distribution of front foot sizes of baited and non-baited dingo populations.
Thomson (1992 b) recorded 272 chases including 37 attacks on kangaroos, 73 cattle - dingo interactions including 26 attacks or purposeful approaches of cattle and 68 chases of sheep, 45 of which ended in the capture of the sheep. We re-analysed the field records of these interactions comparing the prey responses to dingoes between species and the attributes of dingoes attacking the respective prey. The number of dingoes involved in chases and attacks of sheep, kangaroos and cattle and their mean age were extracted from the field recordings of observations and post mortem analysis of teeth (described in Thomson 1992 a & b). As not all members of groups had been captured and examined, mean age of groups attacking prey is calculated from the known-age individuals only.
Statistical Analysis
SEE KERRY ?
(Mean pack size and mean age of collared dingoes was plotted against the average age of a four-tooth wether, mean weight of a female, adult red kangaroo and newborn calf.)
Results
Age of Dispersers and Re-colonisers
Comparison of ages between dispersers, re-colonisers and the ages of all dingoes when first captured in Thomson's study (Table 1) shows no significant difference in the frequency of age classes between adult and yearling dingoes that disperse versus dingoes in the general population. Juveniles, in their first year, are the only age group under-represented in dispersing or re-colonising dingoes.
Comparison of front foot length of dingoes in baited and non-baited areas in Allen and Gonzalez's (1998) study (Figure 1) suggests a similar age structure between stable and re-colonised dingo populations. The mean foot length of baited populations was higher at 6.83 cm (SE 0.03, n = 496) while the non-baited population had an average foot length of 6.63 cm (SE 0.02, n = 919). The difference in the mean is small but statistically significant (P = 0.001). The frequency of adult, foot-sized individuals (>6cm) in the baited area suggests the age structure of mature age dingoes in re-colonised populations is comparable to stable populations.
Group size, age and prey selection
Twenty-seven dingo attacks of kangaroos involving a total of 90 dingoes were observed during Thomson's (1992) studies. The number and respective ages of dingoes involved in killing kangaroos are shown in Table 2. Mean group size in these attacks was 3.3 dingoes ( 0.24, range 1- 6) and the average age of the 38 known-age dingoes was 3.0 years ( 0.31, range 1-7). Seven of the eight kangaroos killed by solitary dingoes were joeys and the eighth was a juvenile.
Eight attacks of feral cattle by dingoes were observed and four calves were killed (Thomson 1992 b). These attacks involved 34 dingoes of which ten were of known age (Table 3). Mean group size was 4.25 dingoes ( 0.37, range 2 - 5) with a mean age of 4.6 years ( 0.68, range 1-7yrs). In addition to these attacks a further six observations were made of dingoes chasing cattle but where an attack did not eventuate. Chases involved 21 dingoes with a mean group size of 3.5 dingoes ( 0.56, range 2 - 5) and the mean age of the nine known-age dingoes was 2.3 years ( 0.42, range 1.5-4.5).
Twenty-six dingo attacks on sheep were observed involving 40 dingoes where the sheep were killed outright or where sheep were badly injured and expected to die (n = 8 and 18 respectively) (Table 4). The mean group size of dingoes killing sheep was 1.5 dingoes ( 0.15, range 1 - 4) and the mean age of the known-age dingoes involved in the 38 attacks was 1.9 years ( 0.23, range 1-4.5).
Plotted against mean weight estimates of sheep (50 kg, pers comm. Sheep and Wool Institute, Toowoomba), kangaroos (26.5kg, Australian Museum 1983) and newborn calves, 30-51kg (Thomas 1986), group size and the mean age of dingoes is not related to prey weight for these species (Table 5).
Sheep killed by dingoes were seldom fed on and only a small proportion was consumed FIGURES? (Thomson 1992b).
Differences in prey behaviour
Sheep were quick to flee from dingoes but were easily outpaced and captured after a short chase. While Thomson (1992b) reported 66.2% (45 of 68) chases ended with the capture of the sheep their efficiency is understated. Dingoes broke off attacks on sheep at times to pursue others more distant.
Kangaroos also fled at the presence of dingoes but their capture necessitated a longer and more strenuous chase. Thomson (1992b) witnessed 272 chases of kangaroos in this study with a capture efficiency of 9.2%. The efficiency of dingoes killing kangaroos was enhanced by increased group size. When more than two dingoes were involved in the chase their capture efficiency was 18.9%. The incidence of kangaroos confronting a dingoes’ threat or challenge behaviour seldom occurred. However, Thomson observed five attacks on kangaroos by groups failed because the kangaroos positioned themselves natural barrier so that only one dingo could attack at a time (Thomson 1992b).
In comparison, 18 of 73 cattle/dingo confrontations observed by Thomson (1992b), adult cattle herded around young calves and on 41 occasions, adult cattle aggressively chased dingoes. Dingoes nevertheless purposefully approached or attacked cattle (threat or challenge behaviour) on 26 occasions when calves were present. Of these occasions, four (15.4%) resulted in calves being killed.

Discussion

Characteristics of dispersers and re-colonisers


If we assume that Thomson, Rose and Kok’s (1992) sample of 205 dingoes is representative and typical of the characteristics of dispersing and subsequent re-colonising dingo populations, then there is little difference in age structure of adult dingoes in stable versus baited populations. The major difference is the size and coordination of the social groups.
Thomson, Rose and Kok (1992) reported that dingo dispersal takes various forms and involves different age and social class animals. Dispersal can be rapid or take place over time. While most dingoes disperse as solitary individuals, Thomson, Rose and Kok (1992) observed splinter groups of pack members and entire packs dispersed as well (25, 5 and 1 respectively). The dingoes most likely to disperse and become colonisers were found to be loners, yearling females or yearling and adult males. Dispersal was highest when the dingo population was high and food availability was low.
Stable populations of dingoes have both pack and lone dingoes although the proportion of lone dingoes is small. Non-pack, yet territorial, dingoes operate in the interstitial spaces between pack territory boundaries. Thomson et al. (1992) describes a range of movements suggesting how some territorial animals go through a process of becoming lone dingoes, commencing with extra-territorial forays, withdrawing to the less frequented portions of the pack’s territory before dispersing altogether from their family group. Stable packs may comprise of 3-23 members. Density of dingoes increases with pack size but fidelity to territory boundaries remains relatively constant throughout flush and drought seasonal conditions.
Whether pack members hunt as individuals or as a group is related to the size of the prey hunted. We conclude that the size of the most profitable species available and the size of the group that most efficiently hunts them, dictates group size. For example, dingoes split up and hunted rats as individuals on the flood plains in the dry season in Kakadu, when previously, through the wet season, groups of dingoes had hunted agile wallabies (Corbett 1995). Similarly, when kangaroos became scarce in Thomson’s (1992b) study, packs disintegrated or abandoned their territory. Prior to that, pack members hunted small prey and scavenged cattle carcasses as individuals.
The age and social status of dispersing and colonising dingoes parallels the published studies of other canids. Crabtree (1988) discovered non-territorial coyotes of one to three years of age, exists in association with stable coyote populations. He concluded that these animals constituted a significant body of replacement animals should mortality or injury lead to the demise of individual pack members. Frittz and Mech (1981) reported that the wolves that colonised the newly protected north-western Minnesota were almost entirely yearling or young adult animals, less than two years of age, which had not previously bred. Wolf populations in Minnesota expanded mainly by way of increasing the numbers of social units following a dispersal strategy of early dispersal and formation of new social units.
Boyd et al (1994) reported that colonising wolves in Glacier National Park area killed a higher proportion of white-tailed deer fawns (Odocoileus virginianus) and elk calves (Cervus elaphus) than did wolves in established populations elsewhere. However, their explanation was that colonising wolves were selecting these preferred age classes relative to their occurrence. Deer and elk populations in Glacier National Park were not previously exploited by wolves and consequently, had a greater occurrence of vulnerable aged fawns and calves compared to populations with a history of wolf predation. Colonising and/or disturbed dingo populations however, kill more calves than dingoes in stable, non-baited areas when the availability of vulnerable calves is no different.
Group size effects
The critical difference between stable and re-colonising populations lies not in younger age animals and reduced hunting experience but in reduced group size and coordination when hunting. Allen and Gonzalez (1998) speculated that baiting disrupted stable packs and resulted in populations of young, inexperienced dingoes re-colonising vacant areas, but the data reported in this study shows that age is not a factor.
These data show dingoes need to hunt in larger groups with more experienced hunters to kill larger, more difficult prey. Dispersers are low ranked members of packs but if their relative age is no different to stable populations, their individual hunting ability should also be similar. Thus, increased mean age and group size (Table 4) reflects the degree of difficulty of capturing prey. Group size increases hunting efficiency by sharing the physiological costs of chasing and attacking prey. Corbett (1995 pg 116-117) observed a pack attacking a cow and calf. He reported that “sub-groups (of the pack) alternated between harassing and resting”. Eventually the cow got too exhausted to continue defending the calf, which was subsequently killed or died from its injuries. Corbett (1995) provides a further example of dingoes sharing the physiological cost of attacking large prey. When a group of six dingoes chased an estimated 200kg buffalo (Bubalus bubalis), the lead dingo nipping at the buffalo’s legs frequently changed during the pursuit. Corbett (1995) and Thomson (unpublished) observed dingoes attracting the aggressive charges of a protective, adult cow, while other dingoes in the group inflicted killing bites on the calf. Thomson (1992b) occasionally noted the combined effort of several dingoes was needed to over-power large kangaroos.
When small to medium-sized prey become available, dingoes switch from group hunting less profitable species like wallabies to hunt smaller mammals like rats (Muridae) (Corbett 1995), possums (Phalangeridae) and bandicoots (Peramelidae) as individuals (Allen & Gonzalez 2000). When dingoes switch to larger, less profitable prey they need to hunt more cooperatively. By sharing the cost of chasing, attacking and killing prey they increase their hunting efficiency.
Feral versus managed cattle
There is a distinction between “cattle” in Thomson’s (1992b) study and the managed cattle herds typical of beef production in central and northern Australia (Allen and Gonzalez 1997). Cattle in Thomson’s (1992) study area were feral, that is, they are un-managed, un-branded, free-ranging animals of intractable dispositions. Relative to domestic cattle, feral cattle have well-developed necks and shoulders (a result of natural selection from fighting), sharp horns yet are rank and undeveloped in the hindquarters. Mortality is high due to disease and poor nutrition. Low reproductive rates exist because of disease, nutrition and aged cows as well. Consequently, in Thomson’s (1992) study, adult cattle made up a large percentage of the population, perhaps as much as 95% and many of the anti-predator defences of ancestral cattle could be expected. In a managed cattle herd bulls typically represent <5% of the adult population (to reduce fighting) and replacement heifers and bulls are selected for temperament. Disease, nutrition, cow age and breeding are controlled producing high reproductive rates. Calves, prior to weaning, typically represent 30% of a managed herd’s population.
Kangaroos were the principal prey in the diet of dingoes in Thomson’s (1992b) study yet wild cattle were more abundant. Nevertheless, in terms of hunting efficiency, calves required relatively no chase and were more efficient and productive prey for dingoes (15.4%) than kangaroos (9.2%). Young calves are within a similar weight range to adult kangaroos (newborn weight of calves, 31-51kg, Thomas 1986, mean adult weight of kangaroos, 17-66kg, Corbett 1995).
Corbett (1995) explains that one of the considerations influencing the dingoes’ choice of prey species is the dingoes particular “search image” and the potential risk of injury to the dingo. He and Thomson (1992b) argue that the protective behaviour of the cow and the potential injury risk results in few attacks of calves. This interpretation is questioned particularly for managed cattle. Maternal behaviour of the cow and calf in the first few weeks after birth shows young calves to be regularly unattended and vulnerable to dingo predation.
Cow and newborn calf behaviour
Rankine and Donaldson’s (1968) observations of Bos idicus cross beef cattle near Mount Garnet and Craig’s (1981) account of the behaviour of “half wild” Camargue cattle of southern France similarly describe the behaviour of cattle in a semi-domesticated state at parturition. According to Rankine and Donaldson (1968) and Craig (1981), semi-domestic cattle generally graze in discrete social groups, but immediately before calving, cows separate themselves from their group to give birth. In intensive cattle herds this behaviour at birth is not common (Houpt 1991). In Camargue cattle, calves remained hidden and apart from the herd for the first three or four days while the mother rejoined the herd, returning only for short periods to allow suckling (Craig 1981). Rankine and Donaldson (1968) observed the same behaviour in North Queensland cattle but claimed calves were not hidden by the cow but just flopped down anywhere. Also that the cow tended to remain in vicinity of the newborn calf rather than return for a few moments when suckling. Every four to six hours however, the cow would have to leave the newborn calf for an hour or more to walk to water, leaving the newborn calf undefended and vulnerable to dingoes.
After this three or four day period of separation, the calf is led to the herd where it joins with other young calves in a nursery group. These crèches or nursery groups typically consist of about ten small calves and a couple of older calves (Corbett 1995) but may have up to 25 calves (Rankine and Donaldson 1968) with only one or two adult cows minding them. Rankine and Donaldson (1968) observed that for the next six weeks, the calves in nursery groups, neither drank water or, travelled with the main group of adult cows to drink.
In these initial few weeks, after the calf is born, Rankine and Donaldson (1968) witnessed dingoes waiting and watching or harassing cows, waiting for the cow to leave the calf for water. They report the vain attempts of some cows, loathe to leave a calf in the presence of dingoes, trying to encourage newborn calves to follow. Rankine and Donaldson (1968) also observed that dingoes were quick to respond to lone calves that would wake from sleep and aimlessly walk along bellowing, trying to locate their mother.
Like Allen and Gonzalez (in prep), Rankine and Donaldson’s (1968) study of calf mortality in a beef cattle herd in north Queensland continued to experience dingo predation subsequent to baiting. Their results showed that the greatest loss of calves between pregnancy and weaning were from dingo attacks that occurred in the peri-natal and immediate post-natal period. The timing and magnitude of their reported calf loss is similar to many reproductive performance studies in northern Australia. Studies across northern Australia show there are significant year and property differences in lactation failure rates which seem unrelated to season, nutrition or stock management (Allen and Gonzalez 1998; Holroyd 1977).
Predator and Prey Behaviour
Dingoes show a similar sequence of behaviours to their prey as wolves. Mech (1970) partitions the hunting behaviour of wolves (Canis lupus lupus) into a relatively predictable sequence of actions of: location, the stalk, the encounter, the rush, the chase, and finally, the attack. Prey species respond to each of these sequences with their own peculiar anti-predator behaviours. In some critical steps the response behaviours of the prey triggers or elicits the predator’s next behaviour in the sequence.
Corbett (1995) and Thomson (1992b), describing the hunting tactics of dingoes, shows that dingoes conform to these generalised predation sequences. According to Corbett (1995), dingoes locate their prey through either direct scenting and tracking, ambush or chance encounters. Stalking behaviour, a slow and alert restrained yet purposeful approach towards an unaware prey (Mech 1970), is not typical of dingo hunting behaviour. Dingoes often ambush prey and take advantage of the confusion they cause or, alternatively, constantly chase a prey until it is overcome or harass a prey until it is too exhausted to defend itself.
How the prey responds after the prey and predator confront each other seems critical. In wolves, a stationary prey can inhibit the rush and subsequent attack response, whereas, a fleeing response by the prey almost always results in a rush and subsequent chase and attack responses. Mech (1970) observes that the same behaviour is true of dogs (Canus lupus familiaris). Dingoes seldom exhibit a stalking behaviour. After prey is encountered, dingoes may challenge a stationary prey with a threatening, lowered head stance, or short charge. If the prey does not flee but faces and confronts the dingo, the dingo will quickly lose interest.
Mech (1970) postulated that the fleeing response of a prey was a critical behavioural cue to the rush and chase response of wolves. For example, he observed wolves stop chasing a caribou (Rangifer tarandus) and even sat down when the caribou turned and confronted them.
The same behaviour is true of dingoes. For example, in 1993, twelve captive-reared dingoes were released onto a 70 km2, uninhabited island in Shoalwater Bay, about 150km northeast of Rockhampton (Allen, Lee & Edwards 1996). The island had a population of 2 000 feral goats and the release was designed to control feral goat numbers and reduce their impact. Within an hour of being liberated an adult male dingo of over 20 kilograms, was observed at close range when he made his first contact with “prey”, an adult female goat. The dingo’s initial response was one of curiosity. Ears pricked and head elevated, he made four or five steps towards the goat. At approximately 15m away the dingo’s head dropped and extended forward and he became completely focussed on the as yet, unsuspecting goat. Several purposeful steps were made towards the goats before the goat noticed him (the confrontation). The goat bleated, alarming its companions, turned and ran (the fleeing). The dingo responded instantly (the rush), bringing down the goat at the first attempt within ten metres (the attack).
In another observation in southeast Queensland, a large male dingo was observed threatening a calf in the presence of the cow. The dingo cautiously approached the calf, watched intently by both cow and calf. Five metres from the calf, the dingo, with head lowered, made two successive quick movements which appeared to be an attempt to make the calf run. The calf walked towards the cow a few metres. The cow, ten metres further distant, responded to the threats by lowering her head and made several aggressive paces towards the dingo. The dingo immediately retreated several yards, lost interest and slowly wandered off.
We propose that the fleeing response of kangaroos, wallabies, rabbits and feral pigs is a significant factor why dingoes prey on these species so consistently. Sheep also flee in a stereotyped response to the presence of danger. This behaviour triggers the dingoes’ response to attack and results in catastrophic results for sheep producers. So incompatible are dingoes and sheep that every effort is given to complete removal of dingoes from sheep producing areas.
Cattle and calves however, seldom flee any distance or at any speed from dingoes and cows often confront and repel dingoes. These actions often fail to elicit or sustain the dingo’s rush and attack behaviour. Prey behaviour is the essential characteristic why young calves are attacked so infrequently, inconsistent with their abundance and weight relative to the optimal weight range of dingoes and the apparent efficiency dingoes can capture them. It is the essential reason why calves are not a more preferred prey to kangaroos.
Domestication of livestock has increased susceptibility to predation
The quick-flee response of sheep to dingoes appears to be a completely inappropriate behaviour as it triggers predator attacks. However, familial sheep are descendants of the European and/or Asian mouflon (Ovis musimon and O. orientalalis respectively) (Microsoft Encarta 1999). These domestic sheep ancestors, together with related species such as Dall sheep (Ovis dalli) and Bighorn sheep (Ovis canadensis) found in the mountains of North America; Urial (O. vignei) from Afghanistan and Pakistan; and Argali (O. ammon) of central Asia, are all inhabitants of high mountains and rocky ranges. Similarly, they share an identical, quick-flee response to wolves, as do domestic sheep to dingoes. Their anti-predator defence depends on their speed and agility to climb steep cliffs to obtain protection. Grazing on pastures adjacent to these structures they flee to these retreats the instant wolves are sighted (Mech 1970; Carbyn 1974). This is their primary defence. Domestication has seen sheep produced in locations that afford no protection from cliffs and rugged mountains. Consequently, the behaviour of domestic sheep is appropriate for the environment where sheep evolved, but not in the environment where sheep are now raised in Australia.
The cattle management practices of dehorning, culling older cows, early weaning, breeding for temperament and limiting the adult male portion of the population compromise the predator defences of domestic cattle. The fact that dingo packs disintegrated in Thomson’s (1992) study in the presence of feral cattle when kangaroos became scarce demonstrates the effectiveness of the predator control behaviours of feral cattle. However, the severe losses recorded in domestic cattle by Allen and Gonzalez (In Prep) Mech (1970) reported accounts of wolf predation on wood buffalo and musk ox. These species adopt similar behaviour to wolves as cattle do to dingoes in that they do not flee. Adult musk ox surround their calves and face outward and use their recurved horns and hooves to charge and ward off wolves.


F
igure 1 Frequency distribution of foot-size measurements taken 1996-1998 from baited (solid columns) and non-baited (shaded) populations.



Table 1 Age distribution of dingoes when first captured compared to the age of dispersers and non-collared dingoes destroyed in sheep country.
Age (years) <1 1 2 3 4 5 6 7 >7

All Captures 101 50 29 9 4 6 2 0 4

Dispersers* 4 17 10 5 1 0 1 1 0
Re-colonisers** 6 5 6 5 0 0 0 0 0
Total dispersed/ 10 22 16 10 1 0 1 1 0 Re-colonised
* Age when first discovered in new territory based on radio tracking.

** Non-collared dingoes captured or shot in sheep country



Table 2 Dingo attacks observed on red kangaroos (Macropus rufus) and euros (M. robustus).
Date Number No. of Dingoes Age Comments in Pack (Identity) (yrs)
3/77 3 1 (421) 2.5
4/77 5 2 (412) 7* 4 attended kill

(421) 2.5


4/77 4 3 (418) 1 418 killed ½ sized roo on his

(422) 1 own

(427) 5.5
10/77 3 2 (427) 6

(479) 7*


11/77 6 1 (427) 6
1/78 5 2 (421) 3

(412) 7*
2/78 2 1 (424) 3


3/78 2 1 (424) 3
3/78 1 1(421) 3.5 Juvenile
6/78 2 1 (420) 4
8/78 3 1 (471) 1

  1. 1

8/78 1 1 (471) 1 Joey


9/78 2 1 (421) 4
10/78 1 1 (441) 2 Joey
11/78 2 1 (472) 1.5
11/78 4 2 (447) 1.5

(478) 3.5


1/79 1 1 (472) 1.5 Joey
1/79 3 1 (428) 2.5
3/79 1 1 (472) 1.5 Joey
4/79 1 1 (478) 3.5 Joey
4/79 3 2 (478) 3.5 Joey

(466) 1.5


5/79 2 1 (478) 4
9/79 1 1 (447) 2 Joey
10/79 4 1 (447) 2
10/79 2 1 (447) 2
3/80 2 2 (186) 1.5 Joey

(493) 1.5


3/80 1 1 (493) 1.5 Joey
5/80 3 1 (112) 2.5
8/80 3 1 (496) 3
9/80 4 1 (496) 2 Joey
8/83 4 2 (306) 7*

(305) 3
11/83 2 1 (180) 2.5 Joey

1/84 5 1 (325) 1
1/84 5 2 (310) 1

(309) 1
4/84 5 1 (325) 1



Table 3 Dingo chases and attacks observed on cattle.

Attacks



Date Number No. Collared Age Prey Killed

in Pack (Identity) (yrs) (Yes/No)
12/78 5 1 (427) 7* Cow/calf No
3/82 2 1 (124) 4.5 Cow/calf No

5/82 4 2 (313) 3.5 Cow/calf Calf

(182) 4.5
4/83 5 1 (151) 5.5 Cow/calves No
4/83 5 2 (182) 4.5 Cow/calf Calf

(300) 1
10/83 4 1 (306) 7* Cow/calf No


11/83 4 1 (306) 7* Cow/calf Calf
11/83 5 1 (301) 1.5 Weaner Yes

Chases (not resulting in attacks)
3/80 3 2 (195) 2.5 Calves

(483) 2.5


1/82 5 - Cow/calf
3/82 2 1 (196) 1.5 Calves
4/82 2 1 (180) 1.5 Calves in mob
2/83 4 3 (182) 4.5 Cow/calf

(300) 1.5

(301) 1.5
3/83 5 2 (182) 4.5 Calf

(302) 1.5


* Age of dingoes calculated as >7 years of age were assumed to be seven years. Age, based on pulp cavity measurements is unreliable in older aged dingoes.


Table 3 Attacks on sheep where the sheep was killed outright or badly mauled and expected to die.
Date No. No. Collared Age Comments

in Pack (Identity) (yrs)


Attacks where sheep were killed
6/78 3 1 (472) 1 Un-collared at kill, 472

chased others


7/78 4 2 (471) 1 471 killed while 472 (472) 1 chased another
7/78 1 1 (193) 1 lamb
2/79 2 2 (471) 1.5 Didn’t feed on kill

(424) 4.5


3/79 1 1 (474) 1.5 lamb
3/79 2 2 (424) 4.5 Two sheep killed

(471) 1.5


3/79 1 1 (481) 1 lamb
2/80 2 1 (447) 1.5 Attacked 3, killed 1
Sheep badly mauled and expected to die
6/78 1 1 (193) 1 left sheep still kicking
7/78 2 1 (472) 1
7/78 1 1 (471) 1
7/78 1 1 (193) 1
8/78 1 1 (471) 1 left mauled sheep to

attack others


8/78 2 1 (472) 1 fed from live sheep
10/78 1 1 (472) 1
11/78 2 1 (441) 2
12/78 2 1 (473) 4 Left when sheep stopped

struggling


1/79 1 1 (474) 1.5
1/79 1 1 (471) 1.5
2/79 1 1 (471) 1.5
2/79 2 2 (424) 4.5

(471) 1.5


2/79 1 1 (474) 1.5
2/79 1 1 (481) 1.5
2/79 1 1 (424) 4.5
2/79 2 2 (424) 4.5

(471) 1.5


4/84 1 1 (311) 1
Total

26 38 31


Table 4. Mean pack size and age of known age dingoes attacking prey.
Kills and Attacks Chases1 Kangaroo Sheep

on Cattle of Cattle Kills Kills


Mean Pack Size 4.25 3.5 3.3 1.5
Mean Age of 4.6 2.4 3.0 1.9

Members of Packs



1 Unsuccessful attacks, cow/calf chased but no physical contact was made
Dingoes involved in attacks
Identity Frequency of observations Age
424* 5 4.5-5 yrs
473 1 4 yrs
441 1 3 yrs
474 3 1.5 yrs
447* 1 1.5 yrs
471* 9 1-1.5 yrs
481 2 1-1.5 yrs
472* 5 1 yrs

193 3 1 yrs



  • Dingoes also involved in observed kangaroo kills

Review of Optimal Forage Theory, principles and assumptions and the concept of profitability in relation to prey and predator behaviour




References

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