Observations on effects of feral pig (Sus scrofa) age and sex on diet

Context Feral pigs (Sus scrofa) are a destructive invasive species that cause damage to ecologically sensitive areas. Management of biodiversity and of feral pigs assumes the diet of pigs of different ages and sexes are similar. Aims We aimed to investigate effects of feral pig age and sex on broad feral pig diet to identify potential at-risk native wildlife species so as to improve biodiversity and feral pig management. Methods Diet was determined by macroscopic analysis of the stomach content of 58 aerially shot feral pigs of mixed ages and sexes. The study occurred in the Macquarie Marshes, New South Wales, a Ramsar wetland of international significance. Results Feral pigs were largely herbivorous, with vegetable matter being found in all stomachs and contributing to a majority of the food material that was present in each stomach, by volume. Adult feral pigs had significantly more grasses and crop material in their stomachs than juveniles, while juveniles had significantly more forbs in their stomachs than adult feral pigs. Vertebrate prey items included frogs, lizard and snake, but no threatened wildlife species. Conclusions Juvenile and adult feral pigs differed in their diet, especially with regards to plant material, which has not been reported previously. There was, however, no difference in the consumption of vertebrate wildlife species between juvenile and adult, or male and female feral pigs. Slow-moving, nocturnal amphibians and reptiles were the most common vertebrate item recorded. Implications Biodiversity and feral pig management should recognise plant diet differences between demographic segments of the feral pig population. Further research is recommended to determine if diet differences also occur for threatened wildlife species, which will require more intensive nocturnal sampling.

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The Effect of an Intensive Shooting Exercise From a Helicopter on the Behaviour of Surviving Feral Pigs.

Wildlife Research ◽

10.1071/wr9960435 ◽

1996 ◽

Vol 23 (4) ◽

pp. 435 ◽

Cited By ~ 14

Author(s):

N Dexter

Keyword(s):

Home Range ◽

Sus Scrofa ◽

New South ◽

Home Range Size ◽

Home Ranges ◽

Diel Variation ◽

Radio Tracking ◽

Feral Pigs ◽

South Wales ◽

North Western

The hypothesis that disturbance from a shooting exercise using a helicopter will influence the behaviour of surviving feral pigs, Sus scrofa, was tested on a population of radio-collared feral pigs in north-western New South Wales. No significant differences existed in hourly distance moved by pigs, diel variation in distance moved by pigs, or home-range size of pigs, between a radio-tracking session conducted immediately before a shooting exercise from a helicopter and a radio-tracking session conducted during and after the exercise. The position of the home ranges of feral pigs did not appear to be affected by the shooting exercise, although several radio-collared feral pigs moved into and out of the study area between tracking sessions. Overall, the results suggest that the disturbance caused by shooting has little effect on the behaviour of surviving feral pigs.

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Movements of Feral Pigs (Sus Scrofa) at Sunny Corner, New South Wales.

Wildlife Research ◽

10.1071/wr9910049 ◽

1991 ◽

Vol 18 (1) ◽

pp. 49 ◽

Cited By ~ 27

Author(s):

G Saunders ◽

B Kay

Keyword(s):

Population Density ◽

Home Range ◽

Sus Scrofa ◽

New South ◽

New South Wales ◽

Home Ranges ◽

Peak Activity ◽

Vegetative Cover ◽

Feral Pigs ◽

South Wales

This study describes the movements of feral pigs at Sunny Corner in eastern New South Wales. Population density at this site was 2 pigs km-2. Twenty-two pigs (12 males and 10 females) were captured and fitted with telemetry transmitters. Aggregate home range for males (10.7 � 6.9 km2) was significantly greater than for females (4.9 � 1.4 km2) as was 24 h home range (1.4� 1.1 km2, males and 0.8 � 0.4 km2, females). Seasonal home ranges were greatest in the winter and smallest in the autumn. These differences were attributed to variations in food availability. During all seasons there was a preference for creeklines that had vegetative cover. This was the result of thermoregulatory needs, refuge availability and food supply. Peak activity throughout the study occurred between 1900 and 2400 hours with little movement during the middle of the day. The implications of these results to management programs are discussed.

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The Behaviour of Feral Pigs, Sus scrofa, in Flocks of Lambing Ewes

Wildlife Research ◽

10.1071/wr9820101 ◽

1982 ◽

Vol 9 (1) ◽

pp. 101 ◽

Cited By ~ 20

Author(s):

PM Pavlov ◽

J Hone

Keyword(s):

Sus Scrofa ◽

New South ◽

New South Wales ◽

Distinct Pattern ◽

Feral Pigs ◽

South Wales

The behaviour of feral pigs in flocks of lambing ewes was studied in New South Wales during autumn and spring in both 1978 and 1979. Pigs were shown to be predators of lambs. Pig activity caused some disturbance to the flock on 77.5% of the observed occasions they were within 100 m of lambing flocks. Lambs were caught in 10 of 42 (23.8%) of observed chases. The feeding sequence on lambs by feral pigs follows a distinct pattern, and carcasses left at different stages of consumption can implicate feral pigs. Pigs were seen to kill one or two lambs in an evening but it is unknown how many lambs one pig may kill during an entire lambing. One individually identifiable pig was seen to kill five times, and harass the flock for up to 2 h, on seven different occasions during the spring 1978 lambing. Both boars and sows were seen to kill lambs.

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The Evaluation of a Feral Pig Eradication Program During a Simulated Exotic Disease Outbreak.

Wildlife Research ◽

10.1071/wr9880073 ◽

1988 ◽

Vol 15 (1) ◽

pp. 73 ◽

Cited By ~ 40

Author(s):

G Saunders ◽

H Bryant

Keyword(s):

New South ◽

New South Wales ◽

Disease Outbreak ◽

Initial Population ◽

Home Ranges ◽

Eradication Program ◽

Feral Pigs ◽

South Wales ◽

Natural Boundaries ◽

Feral Pig

An exercise was conducted to evaluate the effectiveness of plans to eradicate feral pigs in an exotic disease emergency. The study site was an area of 120 km2 on the southern edge of the Macquarie Marshes in western New South Wales. Shooting from a helicopter accounted for 946 pigs at a rate of 39.2 per hour. This was at an average of 1.65 shots and a cost of $11.77 per pig. A further 43 were shot from the ground or trapped. Of an estimated initial population of 1238, 80% was removed. Telemetry studies conducted in conjunction with the exercise indicated that some pigs became attuned to the significance of a hovering helicopter and modified their behaviour to avoid detection. Movements also emphasised the need to match the boundaries of feral pig eradication zones with natural boundaries, where overlapping home ranges are minimal and densities low. Eradication of feral pigs during an outbreak of exotic disease may be an unrealistic goal, and it may be more efficient to aim to eradicate the disease within the feral pig population. This would be achieved by isolating those pigs carrying the infection; it does not necessarily require the removal of all feral pigs.

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A Short-Term Evaluation of Feral Pig Eradication at Willandra in Western New South Wales

Wildlife Research ◽

10.1071/wr9830269 ◽

1983 ◽

Vol 10 (2) ◽

pp. 269 ◽

Cited By ~ 19

Author(s):

J Hone

Keyword(s):

New South ◽

New South Wales ◽

Short Term ◽

Feral Pigs ◽

South Wales ◽

Short Term Evaluation ◽

Term Evaluation ◽

Control And Eradication ◽

Feral Pig

An evaluation was conducted of an attempted eradication of feral pigs by poisoning and shooting, in an area of 50 km2 at Willandra in western New South Wales. Poisoning with 1080 killed 73% of the feral pigs. After the poisoning, 95 of 98 feral pigs seen in the area were shot. The results and their implications for the control and eradication of feral pigs are discussed.

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Moult, Movements, Age and Sex Composition of Mountain Duck, Tadorna tadornoides, Banded at Lake George, N.S.W

Wildlife Research ◽

10.1071/wr9760173 ◽

1976 ◽

Vol 3 (2) ◽

pp. 173 ◽

Cited By ~ 3

Author(s):

JL McKean ◽

LW Braithwaite

Keyword(s):

Sex Ratio ◽

Age Structure ◽

New South ◽

Sex Composition ◽

South Wales ◽

Two Samples ◽

Significant Difference ◽

Moult Migration ◽

Lake George ◽

Age And Sex

Two samples of mountain ducks totalling 1001 birds were trapped and banded at Lake George,N.S.W. A highly significant difference in age structure between the two samples, taken in January 1965 and in February 1970, may be related to major differences in rainfall for the year preceding each sample. The sex ratio was markedly biased in favour of females. Recoveries of birds were nearly all to the south and west and 300-700 km from the banding site. Fully 99 % of recoveries were in States other than New South Wales. Examination of one sample of 679 mountain ducks for moult of primary and secondary wing feathers showed that approximately one-third of the adults were moulting. It was concluded that the birds were possibly normal residents of the region in which most recoveries occurred, and that they make an annual moult migration to Lake George.

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The Demography of Feral Pigs (Sus Scrofa) in Kosciusko National Park, New South Wales.

Wildlife Research ◽

10.1071/wr9930559 ◽

1993 ◽

Vol 20 (5) ◽

pp. 559 ◽

Cited By ~ 16

Author(s):

G Saunders

Keyword(s):

National Park ◽

New South ◽

Seasonal Pattern ◽

New South Wales ◽

Protein Food ◽

Feral Pigs ◽

South Wales ◽

Postnatal Mortality ◽

Alpine Population ◽

Autumn And Winter

The demography of a sub-alpine population of feral pigs was examined at Kosciusko National Park in south-eastern New South Wales. Reproductive data and age structures indicated a seasonal pattern of breeding, most births occurring in summer and autumn. It is proposed that a decreasing availability of high protein food in the autumn and winter months caused reduced rates of conception. Sows produced 0.84 litters per year with postnatal mortality as high as 85%. The population appeared relatively stable at a density of 1.6 pigs kg-2. Hunting, although illegal in a national park, removed 4.4-15.4% of pigs each year. The overall health and body condition of pigs was good, with no evidence of heavy parasitic burdens or disease. Age-specific body weight and body length in this study were greater than those reported for pigs in semi-arid wester New South Wales.

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Movements and Home Ranges of Feral Pigs (Sus Scrofa) in Kosciusko National Park, New South Wales.

Wildlife Research ◽

10.1071/wr9960711 ◽

1996 ◽

Vol 23 (6) ◽

pp. 711 ◽

Cited By ~ 16

Author(s):

G Saunders ◽

B Kay

Keyword(s):

Home Range ◽

National Park ◽

New South ◽

New South Wales ◽

Home Range Size ◽

Range Size ◽

Home Ranges ◽

Minimum Convex Polygon ◽

Feral Pigs ◽

South Wales

The movements of a subalpine population of feral pigs were examined at Kosciusko National Park in southeastern New South Wales. Sufficient data were collected to estimate the home-range area of 20 pigs on the basis of 782 telemetry and trap locations. Mean (+/- s.d.) home-range size (minimum convex polygon method) for males (35.0 t 22.2 km*2) was significantly greater than that for females (1 1.1 +/- 5.2 km*2). Use of capture-recapture distances to estimate home-range size was considered inappropriate. A test for nomadism suggests that, although home ranges of pigs in this environment were larger than those reported for other pigs in Australia, the pigs were essentially sedentary. Management implications for this population are discussed.

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Aerial baiting of feral pigs (Sus scrofa) for the control of exotic disease in the semi-arid rangelands of New South Wales

Wildlife Research ◽

10.1071/wr98072 ◽

2000 ◽

Vol 27 (5) ◽

pp. 531 ◽

Cited By ~ 29

Author(s):

Peter J. S. Fleming ◽

David Choquenot ◽

Richard J. Mason

Keyword(s):

New South ◽

New South Wales ◽

Effective Density ◽

Contingency Planning ◽

Tissue Samples ◽

Feral Pigs ◽

The Third ◽

South Wales ◽

Arid Rangelands ◽

North Western

An experiment that held the density of feral pigs constant while varying the effective density of aerially distributed baits was conducted at three sites in north-western New South Wales. Meat baits, containing one of the biomarkers iophenoxic acid, tetracycline or rhodamine B, were distributed at different intensities over each site, and a sample of pigs was shot from a helicopter at each site to determine bait uptake. Serum and tissue samples taken from each pig were analysed for the occurrence of the biomarkers; the proportions of pigs exhibiting biomarkers represented the proportions of the feral pig populations that had consumed baits at different baiting intensities (expressed as baits per unit of pig density). The maximum percentage of sampled pigs that had eaten baits varied from 31% to 72% across the three sites. Bait uptake was regressed against baiting intensity. For two of the trials, the quantity of bait hypothetically required to eliminate a population of feral pigs was extrapolated to be 1577 baits per unit of pig density, while for the third trial 1874 baits per unit of pig density would have been required. Bait-uptake by non-target animals was substantial, posing potential hazards to birds and reducing the availability of baits to feral pigs. Most likely, seasonal conditions affected bait-uptake by feral pigs. We discuss the implications of these results for exotic disease contingency planning.

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