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1
Giffney, R. A., T. Russell, and J. L. Kohen. "Age of road-killed common brushtail possums (Trichosurus vulpecula) and common ringtail possums (Pseudocheirus peregrinus) in an urban environment." Australian Mammalogy 31, no. 2 (2009): 137. http://dx.doi.org/10.1071/am09016.
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Road-associated mortality has been identified as having major ecological effects on small, fragmented and declining populations. Both the common brushtail possum (Trichosurus vulpecula) and common ringtail possum (Pseudocheirus peregrinus) appear to be in decline in some regions across their natural ranges. Urban populations may be an exception; however, little is known of their population ecology. This study investigates age trends in a subset of road-killed brushtail and ringtail possums collected along eight northern Sydney roads between March 2004 and March 2006. From a total of 591 recorded road-killed possums, 86 were collected for use in this study (36 brushtails, 50 ringtails). Age was estimated using tooth wear patterns on cleaned skulls. Both species showed trends associated with age, and younger possums of both species were more likely to be killed on roads than older animals. Male-biased dispersal of subadult possums is considered a major contributing factor to the over-representation of young brushtail possums in this road-kill sample.
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Harper, Michael J. "Home range and den use of common brushtail possums (Trichosurus vulpecula) in urban forest remnants." Wildlife Research 32, no. 8 (2005): 681. http://dx.doi.org/10.1071/wr04072.
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The common brushtail possum (Trichosurus vulpecula) is an arboreal marsupial that has adapted well to urban landscapes. Fifteen adult possums (12 female, 3 male) caught in small patches of indigenous vegetation (remnants) in the south-east of metropolitan Melbourne were radio-tracked over a three-month period to investigate nocturnal behaviour and den use. Minimum convex polygon (100%) home-range estimates of both female (1.02 ± 0.28 ha) and male (1.19 ± 0.33 ha) urban brushtail possums trapped in urban forest remnants appear to be smaller than those previously reported for urban brushtail possums. All the brushtail possums foraged extensively in remnants but made repeated forays into adjacent residential areas. The use of few dens, by both female (2.21 ± 0.35 ha) and male (2.51 ± 1.45 ha) brushtail possums, in close proximity to their nocturnal ranges is similar to the behaviour of non-urban brushtail possums
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Russell, Tracey C., Catherine A. Herbert, and James L. Kohen. "High possum mortality on urban roads: implications for the population viability of the common brushtail and the common ringtail possum." Australian Journal of Zoology 57, no. 6 (2009): 391. http://dx.doi.org/10.1071/zo09079.
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Animal–vehicle collisions impact wildlife populations and in the northern suburbs of Sydney, both the common brushtail possum (Trichosurus vulpecula) and the common ringtail possum (Pseudocheirus peregrinus) are killed in large numbers. Over a two-year period almost 600 road-killed possums were observed from 217 road surveys covering over 7800 km, equating to 5.45 possums per week over the 36-km study area. Surveys were conducted along roads where the environment ranged from low-rise suburban to continuous sclerophyll forest. Significantly more ringtail possums were observed as road-kill, outnumbering brushtail possums by almost three to one. No sex bias was found amongst road-killed ringtail possums; however, seasonal trends and weight fluctuations were significant, with both males and females being at their lowest weights during the autumn breeding season. For brushtail possums a bias towards young males was observed. Sex and weight of road-killed brushtail possums were comparable to live-trap data from a previous study in the same location. In areas of such high possum mortality, wildlife managers may need to take action to mitigate possum road-kill.
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Russell, Tracey Catherine, Ellen Geraghty, and Sarah Wilks. "Brushtail possums: do present law, policy and management approaches meet the needs of this species in all its contexts?" Australian Journal of Zoology 61, no. 1 (2013): 95. http://dx.doi.org/10.1071/zo12125.
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Brushtail possums (Trichosurus vulpecula) have been variously described as endangered, pests, prized native wildlife and, recently, as a potential meat export. This article reports information on the increasing decline of the brushtail possum and on attitudes towards these animals. The ‘fit’ between values and attitudes and prevailing governance arrangements is assessed. While the range of this animal is certainly shrinking, areas do exist where the brushtail possum is present at high or very high densities. It is in these areas of high possum density (some urban areas and certain agricultural regions) that conflicts arise, both over the ‘identity’ of the brushtail possum and as to what would be appropriate management. It is argued that although brushtail possums enjoy significant legal protection, these provisions are treated as a nuisance to be circumvented by many residents in areas where possums are in high abundance. Existing policies on possum management somewhat unhelpfully focus attention on situations where possums are overabundant, thus overshadowing situations where active management of declining possum populations would be appropriate.
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Isaac, JL. "Possums: The Brushtails, Ringtails and Greater Glider. Anne Kerle. A Review by Joanne L Isaac." Australian Mammalogy 24, no. 2 (2002): 249. http://dx.doi.org/10.1071/am02249.
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DESPITE their almost ubiquitous presence across Australia, contemporary research on the biology, ecology and conservation status of the so-called 'common' possums is scant and inadequate. The majority of possum studies have been a result of the huge research effort in New Zealand to control and eradicate the common brushtail possum, a notorious introduced pest, and have concentrated primarily upon reproductive physiology. The conspicuous lack of ecological data on the larger possums across their native Australian range is particularly disturbing since evidence suggests that a number of these species are disappearing from large tracts of Australia. However, Possums: the brushtails, ringtails and greater glider, part of the Australian Natural History Series, provides a long overdue summary of up-to-date research on these familiar and intriguing marsupials.
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Day, T. D., and C. E. O'Connor. "Behavioural Adaptation of Brushtail Possums (Trichosurus Vulpecula) to Captivity." Animal Welfare 9, no. 4 (November 2000): 413–20. http://dx.doi.org/10.1017/s0962728600022995.
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AbstractBrushtail possums, Trichosurus vulpecula, are New Zealand's most serious vertebrate pest, facilitating the spread of bovine tuberculosis to livestock, and causing severe damage to native flora and fauna. Possum control has become a national research priority, involving the use of large numbers of captive possums. Successful adaptation of these animals to captivity is important for the welfare of the possums and for the validity of experimental results. The objective of this study was to determine, by behavioural means, the time individually caged possums required for adaptation to captivity. We used a simple behavioural measure - a possum's daily response to a caregiver at feeding (a feeding test) - to assess changes in the behaviour of possums after arrival in captivity. We also recorded changes in possum body weight throughout this period. Initially most possums ‘avoided’ the caregiver, but within 7 days more than 80 per cent of animals no longer avoided. ‘In den’ and ‘approach’ behaviour rapidly increased for the first 14 days in captivity, after which den use became less common as more possums ‘approached’ the caregiver. By day 29 of captivity, more than 80 per cent of the possums ‘approached’ the caregiver. The possums’ body weight did not change significantly during the first 14 days in captivity, but had increased significantly by day 28, and continued to increase for at least 6 weeks after capture. These data suggest that most possums adapt to captivity within 4 weeks. For the welfare of possums and the reliability of experimental results, we recommend that possums are not used in experiments until at least 4 weeks after capture.
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Kerle, J. A. "The population dynamics of a tropical possum, Trichosurus vulpecula arnhemensis Collett." Wildlife Research 25, no. 2 (1998): 171. http://dx.doi.org/10.1071/wr96113.
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The population ecology of Trichosurus vulpecula has been studied extensively in temperate Australia and in New Zealand. This paper provides the results of a trapping study of a population of the northern brushtail possum (T. vulpecula arnhemensis Collett 1897) in the wet–dry tropics of Australia’s Northern Territory. Possums were readily trapped and the population had a comparatively high density for Australian brushtails of around 3 per hectare. The core home-range size and range length for males was 1.12 ha and 165 m; this was a little larger than for females (0.89 ha and 155 m). The possums were not very agressive when handled and were apparently quite socially tolerant. The ready availability of nutritious food sources throughout the year enables them to breed continuously, producing 1.7 young per year per adult female. If environmental conditions become unfavourable with a series of poor wet seasons or frequent fires, the habitat will resemble the less-productive eucalypt forest not occupied by possums. Mortality of pouch young and immatures will increase under these conditions but with a potential reproductive rate of nearly two per year, populations of the northern brushtail can readily recover from short periods of unfavourable conditions.
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Marsh, Karen J., Ian R. Wallis, and William J. Foley. "The effect of inactivating tannins on the intake of Eucalyptus foliage by a specialist Eucalyptus folivore (Pseudocheirus peregrinus) and a generalist herbivore (Trichosurus vulpecula)." Australian Journal of Zoology 51, no. 1 (2003): 31. http://dx.doi.org/10.1071/zo02055.
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The paucity of evidence on eucalypt browsing by common brushtail and common ringtail possums suggests that ringtails preferentially eat foliage from trees within the subgenus Monocalyptus. In contrast, brushtails eat less eucalypt foliage than do ringtails and prefer trees from the subgenus Symphyomyrtus. Trees from these subgenera differ in their defensive chemicals. Both contain tannins but it appears that only the symphyomyrts synthesise formylated phloroglucinol compounds (FPCs). We fed possums foliage from several individual Eucalyptus rossii and E. consideniana, both monocalypts, to avoid the confounding factor of FPCs, and examined the effects of blocking tannins by dipping foliage in polyethylene glycol (PEG). Ringtails and brushtails differed in their abilities to eat foliage from these eucalypts. The ringtails ate much more than did the brushtails and showed a small (about 10%) but significant increase in feeding in response to PEG. The brushtails were reluctant to eat foliage from either eucalypt species but doubled their intake when leaves were coated with PEG. Even so, they still did not eat enough to meet maintenance requirements for energy and nitrogen. Neither ringtails nor brushtails preferred foliage from any individual E. rossii tree, suggesting that all trees were equally defended. However, brushtails preferred foliage from some E. consideniana to others. Monocalypt tannins are clearly important barriers to feeding in brushtail possums, but further research with higher doses of PEG will confirm whether they are the only deterrent chemicals in monocalypt foliage.
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Wallis, I. R., M. L. Watson, and W. J. Foley. "Secondary metabolites in Eucalyptus melliodora: field distribution and laboratory feeding choices by a generalist herbivore, the common brushtail possum." Australian Journal of Zoology 50, no. 5 (2002): 507. http://dx.doi.org/10.1071/zo02029.
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We studied the influence of a group of plant secondary compounds, the sideroxylonals, on feeding by the common brushtail possum (Trichosurus vulpecula), a generalist herbivore. Possums were offered synthetic diets either with or without sideroxylonals or, in separate experiments, foliage from 28 individual Eucalyptus melliodora trees. Possums ate less of the synthetic diet at sideroxylonal concentrations of 4 and 7 mg g–1 when offered a choice or no choice, respectively. Possums fed foliage in no-choice protocols ate 12–61 g of dry matter per day. Sideroxylonal concentration was an essential determinant of feeding on foliage but the wide variation, particularly at intermediate sideroxylonal concentrations, suggests that other secondary plant chemicals, e.g. tannins, are important also. The normal distribution of sideroxylonal concentrations (mean = 27.7, s.d. = 7.85 mg sideroxylonals per g dry leaf) in a natural population of 150 E. melliodora trees shows that brushtail possums will rarely encounter highly palatable trees (<10 mg sideroxylonals per g dry leaf) nor highly unpalatable foliage (>40 mg sideroxylonals per g dry leaf). When foraging on E. melliodora, brushtail possums must contend with intermediate sideroxylonal concentrations (20–30 mg per g dry leaf), where variability in food intake is most noticeable.
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Eason, CT, D. Batcheler, and CM Frampton. "Comparative Pharmacokinetics of Iophenoxic Acid in Cats and Brushtail Possums." Wildlife Research 21, no. 3 (1994): 377. http://dx.doi.org/10.1071/wr9940377.
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The comparative plasma pharmacokinetics of iophenoxic acid was studied in the cat and brushtail possum (Trichosurus vulpecula) to evaluate the suitability of this compound as a bait marker in these species. In cats, a mean peak plasma concentration of 946 micro g per 100 ml was obtained after administration of 1.5 mg/kg of iophenoxic acid. However, at the same dose level in possums, mean peak plasma concentration was only 157 micro g per 100 ml. Even after administration of 10 mg/kg of iophenoxic acid, the maximum peak plasma concentration in possums was only 459 micro g per 100 m/litre. The plasma elimination half-life for iophenoxic acid was 107 days in cats and close to one day in possums. Iophenoxic acid is therefore a suitable marker for cats but is unsuitable for use as a long-term or quantitative bait marker for possums. Differences between the possum and other mammals in gastrointestinal physiology and plasma protein configuration by account for the poor absorption and rapid elimination of iophenoxic acid in the possum.
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Caley, P., N. J. Spencer, R. A. Cole, and M. G. Efford. "The effect of manipulating population density on the probability of den-sharing among common brushtail possums, and the implications for transmission of bovine tuberculosis." Wildlife Research 25, no. 4 (1998): 383. http://dx.doi.org/10.1071/wr97029.
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Common brushtail possums (Trichosurus vulpecula) act as a reservoir of bovine tuberculosis (Mycobacterium bovis) in New Zealand and the simultaneous sharing of dens may result in the transmission of Tb between possums. The effect of manipulating population density on the per capita probability of simultaneous den-sharing among possums was investigated at a site near Dunedin, New Zealand. Den characteristics that could affect the probability of simultaneous sharing were also investigated, though none were found to be significant. The daily probability of a possum sharing a den was estimated to be 0.07 for possums denning within uncontrolled areas of the study area. Den-sharing was most common between female pairs, though sharing was also recorded between male–female and male–male pairs. The highest number of possums recorded sharing a single den was four. Reducing population density significantly lowered the probability of possums simultaneously sharing dens within the study area, with greater than 60% reductions estimated to eliminate simultaneous den-sharing altogether. The relationship between the contact rate arising from den-sharing and population density was convex-down, rather than convex-up, as often hypothesised for animal–animal disease contact processes. The implications of simultaneous den-sharing for the transmission and control of bovine tuberculosis in brushtail possum populations are discussed.
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Frampton, C. M., B. Warburton, R. Henderson, and D. R. Morgan. "Optimising bait size and 1080 concentration (sodium monofluoroacetate) for the control of brushtail possums Trichosurus vulpecula)." Wildlife Research 26, no. 1 (1999): 53. http://dx.doi.org/10.1071/wr98013.
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A method is presented for quantitatively assessing the likely effectiveness of specific bait size and 1080 concentration for controlling brushtail possums with a known weight distribution. Data from aerial 1080 operations for the control of brushtail possums in New Zealand show that estimates of the bait size and toxic concentration required derived from the mean parameters [pest weight, bait size, and lethal dose (LD 95)] will not be accurate. This inaccuracy is most likely to lead to an underestimate of the amount of toxin presented to each animal, so that many operations currently run the risk of sub-lethally dosing possums and thereby possibly inducing some degree of poison shyness. On the basis of more accurate quantitative assessments of bait effectiveness we recommend that the 1080 concentration be increased to 0.15% and that baits less than 5 g be excluded to ensure that when mean possum weights are less than 3 kg more than 95% of possums are lethally dosed by a single bait.
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Clark, P. "Haematological and biochemical values for brushtail possums." New Zealand Veterinary Journal 46, no. 3 (June 1998): 118. http://dx.doi.org/10.1080/00480169.1998.36073.
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Mella, Valentina S. A., Jordan Krucler, Lakshmi Sunderasan, Jason Hawkins, Anushika P. H. M. Herath, Kyla C. Johnstone, Sandra M. Troxell-Smith, Peter B. Banks, and Clare McArthur. "Effective field-based methods to quantify personality in brushtail possums (Trichosurus vulpecula)." Wildlife Research 43, no. 4 (2016): 332. http://dx.doi.org/10.1071/wr15216.
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Context There is growing recognition of the importance of animal personality in wildlife ecology and management. Individuals that differ consistently in their behaviours from others of the same population are considered to exhibit different personalities. Personality can be easily quantified with repeat tests on animals held in captivity. However, captive-based tests may not always be possible for logistical reasons and tests conducted in captivity can alter naturally occurring behaviours. Development of methods to assess personality in the field over short-term capture is an important alternative to long-term captive tests. Aims To develop and refine field-based tests that can be used to easily define personality traits of wild common brushtail possum (Trichosurus vulpecula), eliminating the need to bring individuals into captivity for an extended period of time. Methods We developed a series of short-term capture protocols to quantify personality traits of the common brushtail possum in the field, using handling-bag tests, modified open-field tests, trap-behaviour tests and release tests. Key results Personality traits of brushtail possums could be measured in several different ways, but refining methods was crucial to reveal traits efficiently. Behaviours related to several personality traits (boldness, docility and activity/exploration) could be measured rapidly in the field with our methods, and were repeatable over time. Conclusions Rapid, reliable and easy-to-perform quantification of personality of brushtail possums in the field is possible. This may sometimes be the only available option, and has advantages over long captive trials in terms of animal welfare and cost. Implications The present study provides a baseline for future research on the personality of common brushtail possums and its application to management and control strategies for the species.
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Anderson, Hannah, Leonie E. Valentine, Giles E. St J. Hardy, and Patricia A. Fleming. "Relationship between the common brushtail possum (Trichosurus vulpecula) and tuart (Eucalyptus gomphocephala) tree decline in Western Australia." Australian Mammalogy 42, no. 1 (2020): 67. http://dx.doi.org/10.1071/am18019.
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Forest canopy loss due to plant pathogens, insect or abiotic factors significantly alters habitat and resource availability for animals, which has flow-on effects for whole ecosystems. The tuart (Eucalyptus gomphocephala) has been in decline throughout its geographic range; this is likely associated with watertable and salinity changes, although a plant pathogen (Phytophthora multivora) has also been implicated. We examined the relative abundance of common brushtail possums (Trichosurus vulpecula) across 12 sites (each 0.72 ha) selected on the basis of the health of dominant tuart trees (six ‘healthy’ and six ‘declining’ sites). Habitat variables (understorey, tuart dimensions and density, tree hollows, tree-to-trap distance) and tuart tree health (crown loss, epicormic regrowth) were compared with possum abundance. Possums were detected at most sites. There was no significant difference between brushtail possum numbers at ‘healthy’ or ‘declining’ sites, although marginally more possums were recorded at declining sites (5.7 ± 1.5 (s.e.), n = 6 sites) compared with healthy sites (3.3 ± 0.7; Cohen’s effect size d = 0.80). Slightly higher abundance of possums was associated with sites that had a greater density of smaller-diameter but taller tuart trees. ‘Declining’ sites, with more epicormic regrowth and greater tree densities, may provide more palatable food resources for possums.
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Littin, K. E., C. E. O'Connor, and C. T. Eason. "Comparative effects of brodifacoum on rats and possums." New Zealand Plant Protection 53 (August 1, 2000): 310–15. http://dx.doi.org/10.30843/nzpp.2000.53.3701.
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The anticoagulant brodifacoum is widely used overseas as a rodenticide and in New Zealand to control rodents and brushtail possums (Trichosurus vulpecula) The efficacy behavioural and pathological changes and times to death were compared between Norway rats (Rattus norvegicus) and brushtail possums poisoned with brodifacoum Caged animals were given brodifacoum in wax or cereal baits observed for signs of toxicosis and changes in behaviour then autopsied after death Brodifacoum caused haemorrhaging and death in both species and although each showed marked changes in behaviour and pathology they differed in character time of onset and duration Results may be explained in part by species differences in behaviour and halflives of blood clotting factors
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Eymann, Jutta, Catherine A. Herbert, Brian P. Thomson, Tim E. Trigg, Desmond W. Cooper, and Douglas C. Eckery. "Effects of deslorelin implants on reproduction in the common brushtail possum (Trichosurus vulpecula)." Reproduction, Fertility and Development 19, no. 8 (2007): 899. http://dx.doi.org/10.1071/rd07046.
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The present study investigated the effects of slow-release implants containing the gonadotrophin-releasing hormone (GnRH) agonist deslorelin on reproduction in the common brushtail possum (Trichosurus vulpecula). Captive female brushtail possums were assigned to control (placebo implant), low dose (4.7 mg deslorelin) or high dose (9.4 mg deslorelin) groups; males were assigned to control or high dose (9.4 mg deslorelin) groups. The acute effects of deslorelin treatment at the level of the pituitary gland were similar between the two sexes, where a transient rise in luteinising hormone concentration was induced over the first 24 h. In females, this was associated with the disruption of the normal oestrous cycle and mating within 2–10 days in some treated individuals, but no young were subsequently detected. By 3 weeks after treatment, treated females became anoestrus and remained infertile for at least one breeding season. The effects of treatment were reversible in a subset of females that had their implants removed, although the time taken to produce offspring was variable. Paradoxically, male brushtail possums remained fertile during chronic deslorelin exposure. Despite significant declines in basal follicle-stimulating hormone and testosterone concentrations, as well as an inability to respond to a GnRH challenge, treated males sired as many offspring as control males and there was no evidence of testicular regression. In conclusion, there is potential to control reproduction in female brushtail possums by using chronic GnRH agonist treatment.
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Ramsey, Dave, Murray Efford, Steve Ball, and Graham Nugent. "The evaluation of indices of animal abundance using spatial simulation of animal trapping." Wildlife Research 32, no. 3 (2005): 229. http://dx.doi.org/10.1071/wr03119.
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We apply a new algorithm for spatially simulating animal trapping that utilises a detection function and allows for competition between animals and traps. Estimates of the parameters of the detection function from field studies allowed us to simulate realistically the expected range of detection probabilities of brushtail possums caught in traps. Using this model we evaluated a common index of population density of brushtail possums based on the percentage of leg-hold traps catching possums. Using field estimates of the parameters of the detection function, we simulated the relationship between the trap-catch index and population density. The relationship was linear up to densities of 10 possums ha–1. We also investigated the accuracy (bias and precision) of the trap-catch index for possums to estimate relative changes in population density (relative abundance) under conditions of varying detection probability, and compared these results with those obtained using a removal estimate of the population in the vicinity of trap lines. The ratio of trap-catch indices was a more precise estimator of relative abundance than the ratio of removal estimates but was positively biased (i.e. overestimated relative abundance). In contrast, the ratio of removal estimates was relatively unbiased but imprecise. Despite the positive bias, the trap-catch index had a higher power to determine the correct ranking between population densities than the removal estimate. Although varying detection probability can bias estimates of relative abundance using indices, we show that the potential for bias to lead to an incorrect result is small for indices of brushtail possum density based on trapping.
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Sakaguchi, Ei, and Ian D. Hume. "Digesta retention and fibre digestion in brushtail possums, ringtail possums and rabbits." Comparative Biochemistry and Physiology Part A: Physiology 96, no. 2 (January 1990): 351–54. http://dx.doi.org/10.1016/0300-9629(90)90704-v.
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Cown, PE, and DS Rhodes. "Restricting the movements of brushtail possums (Trichosurus vulpecula) on farmland with electric fencing." Wildlife Research 19, no. 1 (1992): 47. http://dx.doi.org/10.1071/wr9920047.
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A trial was conducted to test whether an electric fence would limit local movements of brushtail possums (Trichosurus vulpecula) on farmland in the central North I. of New Zealand. If effective, such a system could be used to reduce possum and cattle interactions and the spread of bovine tuberculosis. A 3-km-long, 9-strand electric fence was erected from ridge to ridge across a valley catchment of about 160 ha. Possums were live-trapped and released at bush patches within the study area and in open areas immediately adjacent to the electric fence. Only about 30% of possums caught at local bush patches were ever retrapped at the fence, and most were caught only once at the fence. About a third of possums caught at the fence were trapped at least once on both sides of the fence. The electric fence reduced possum movements through the fenced area by about 60-80%. Most possums trapped at the fence had come from bush patches within 200 m of the fence. When the fence was switched off, possum captures on the outside increased rapidly. The effectiveness of the fence was reduced because of frequent voltage reduction by earthing from a wide variety of causes, and because possums learned to move around the ends of the fence and the fences along the farm roads. Improvements to fence design are discussed.
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Gemmell, R. T. "Breeding Biology of Brushtail Possums Trichosurus vulpecula (Marsupialia, Phalangeridae) in Captivity." Australian Mammalogy 18, no. 1 (1995): 1. http://dx.doi.org/10.1071/am95001.
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The brushtail possum is a common arboreal marsupial that is well adapted to the Australian urban environment and to rearing in captivity. Data obtained from 100 female possums housed in a semi-captive colony over a 7 year period demonstrate the reproductive capability of this marsupial. The main breeding season is from March to June with a declining number of births occurring from July to October. The possums gave birth to 259 single young and one set of twins. The range of the lactation period was from 177 to 200 days with the birth of the subsequent young occurring at 188.4 ± 4.1 days post partum (SD, n = 5). The growth rate of the young female possum varied greatly after day 100 post partum, the mean body weight of possums at day 172, being 753.0 ± 76.2g (SD, n = 5) with a range of 685 to 851 g. Female possums, with a mean body weight of 2171 ± 388g, gave birth to their first litter on day 345.9 ± 69.3 days postpartum (mean, SD, n = 7). Although two female possums trapped in the wild were held in captivity for 64 and 63.4 months and one possum bred in captivity had a life span of 51.5 months, the mean life span was 21.0 ± 12.5 months (SD, n =3D 8), with a range of 14.3 to 51.5 months. This life span is very variable and it is of interest to determine if this is an artefact of captivity or is also observed in the wild.
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Ball, Stephen J., David Ramsey, Graham Nugent, Bruce Warburton, and Murray Efford. "A method for estimating wildlife detection probabilities in relation to home-range use: insights from a field study on the common brushtail possum (Trichosurus vulpecula)." Wildlife Research 32, no. 3 (2005): 217. http://dx.doi.org/10.1071/wr03125.
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Using field data from brushtail possums (Trichosurus vulpecula), we present a method for modelling wildlife detection probabilities. Whereas detection functions typically (e.g. for distance sampling) describe the probability of direct human observations of animal subjects, we adapted this approach for cryptic species where observation depends on animals being caught in traps. Specifically, we characterised the probability of individual brushtail possums being caught by leg-hold traps in an area of farmland and native forest in New Zealand. Detection probability was defined as the per-individual, per-trap, per-night probability of a possum being captured, and was modelled as a function of home-range utilisation. Radio-telemetry was used to define the home-range distributions of 18 possums, and a combination of scanning radio-receivers and movement-activated video-cameras recorded instances when radio-collared possums encountered and stepped on the trigger of leg-hold traps (inactivated by being wired open). We estimated a 5% chance of trapping individual possums with a single leg-hold trap located in the centre of their home range for one night (median value across possums). Furthermore, this probability decreased rapidly as a function of distance, so that at 120 m from the centre of the home range there was less than a 1% chance of trapping success per possum per night. The techniques developed in this study could be applied to a wide variety of species and sampling methods.
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Kerle, JA, and CJ Howe. "The Breeding Biology of a Tropical Possum, Trichosurus-Vulpecula-Arnhemensis (Phalangeridae, Marsupialia)." Australian Journal of Zoology 40, no. 6 (1992): 653. http://dx.doi.org/10.1071/zo9920653.
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The breeding biology of Trichosurus vulpecula has been studied in some detail for temperate populations but not for the northern brushtail possum (T. v. arnhemensis), the tropical form of this species. Data for the distribution of births and sex ratio of the young, growth and development of the young and reproductive cycles of both males and females were obtained. Most data were collected from a captive breeding colony of northern brushtails and supplemented with data from wild populations. The reproduction, growth and development of T. v. arnhemensis are very similar to those already described for other populations of T vulpecula. The observed differences can be explained by variation in the size of the animals and the absence of a restricted breeding season. Neither males nor females showed any periodicity in their reproductive strategy. This continuous breeding cycle can be attributed directly to their tropical environment. These tropical possums occupy a stable habitat, mature early and have a higher reproductive effort than populations in more seasonal and unpredictable environments. This suggests that the northern brushtail has a stochastic or 'bet-hedging' reproductive strategy.
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Harper, Michael J., Michael A. McCarthy, and Rodney van der Ree. "The use of nest boxes in urban natural vegetation remnants by vertebrate fauna." Wildlife Research 32, no. 6 (2005): 509. http://dx.doi.org/10.1071/wr04106.
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Nest boxes are routinely installed as a substitute for natural tree hollows to provide den and nest sites for a range of hollow-utilising fauna. We installed 120 nest boxes in 20 patches of indigenous vegetation (remnants) across the urban/suburban landscape of Melbourne, south-eastern Australia, and investigated their use by indigenous and exotic vertebrate species over a period of 12 months. Nest-box use was dominated by the common brushtail possum (Trichosurus vulpecula), the common ringtail possum (Pseudocheirus peregrinus) and the common myna (Acridotheres tristis), an aggressive introduced bird. We found that brushtail and ringtail possums utilised nest boxes all year round but more frequently in cooler months (May–August). Common mynas dominated nest-box use during spring/summer, potentially reducing the availability of this resource to indigenous species. We found evidence that the probability of a nest box being occupied by either species of possum was greater in remnants with abundant possum populations. Brushtail possums preferred thick-walled pine nest boxes over thin-walled plywood nest boxes, most likely owing to differences in their thermal insulation properties. Although considerable economic costs would be involved in using nest boxes as a long-term substitute for hollow-bearing trees, nest boxes may provide a temporary hollow resource until hollow-bearing trees are recruited in urban remnants.
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Curlewis, JD, and GM Stone. "Reproduction in Captive Female Brushtail Possums, Trichosurus-Vulpecula." Australian Journal of Zoology 34, no. 1 (1986): 47. http://dx.doi.org/10.1071/zo9860047.
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Basic reproductive data were collected from a group of wild-caught brushtail possums during three breeding seasons. The mean (�SE) oestrous cycle length, gestation length and interval from removal of pouch young (RPY) to oestrus were 26.3 � 1.46 (n = 39), 17.1 � 0.14 (n = 21) and 9.0 � 0.46 (n = 41) days respectively, agreeing closely with previously published reports. Sperm were first observed in the vaginal smear on days 0 and 1 of the cycle in mated animals, but 27% of matings did not result in the production of a neonate. There was no effect of age of pouch young on the interval between RPY and oestrus but the incidence of mating was greater when pouch young were removed at an early age. In 25 animals examined during an oestrous cycle corpora lutea or Graafian follicles were unequally distributed between left and right ovaries. During the course of the study, four animals were identified in which oestrus was not followed by a luteal phase.
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Day, T. D., C. E. O’Connor, J. R. Waas, and L. R. Matthews. "Social interactions among captive brushtail possums (Trichosurus vulpecula)." Applied Animal Behaviour Science 70, no. 2 (December 2000): 157–65. http://dx.doi.org/10.1016/s0168-1591(00)00144-1.
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Efford, Murray, Bruce Warburton, and Nick Spencer. "Home-range changes by brushtail possums in response to control." Wildlife Research 27, no. 2 (2000): 117. http://dx.doi.org/10.1071/wr99005.
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Common brushtail possums (Trichosurus vulpecula) are intractable pests in New Zealand. The effectiveness of local control can be limited by immigration, some of which has been attributed to a ‘vacuum effect’ – directed movements induced by the control itself. To characterise the vacuum effect we examined changes in the home ranges of trapped possums following control in a 6-ha block at one end of a 13-ha forest patch on farmland near Dunedin, New Zealand. We also monitored a sample of possums by radio-telemetry. After control, the density was 3 ha–1 inside the removal area and 16 ha–1 outside. During the year after the removal, 29% of possums within 100 m of the boundary of the removal area (n = 38) shifted their range centre at least 50 m towards it. The effect diminished rapidly with distance: only 1 of 28 animals moved more than 200 m from the boundary. The size of the previous range was a significant predictor of movement among males, but this may be partly a sampling artifact. We measured a net flux of 69 possums km–1 across the boundary in the 12 months after control, and possums settled on average 44 6.9 m inside the boundary. The vacuum effect in brushtail possums appears largely confined to home-range adjustments by individuals with ranges overlapping the area of reduced density. This limits its potential role in population recovery.
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Hill, Nichola J., Elizabeth M. Deane, and Michelle L. Power. "Prevalence and Genetic Characterization of Cryptosporidium Isolates from Common Brushtail Possums (Trichosurus vulpecula) Adapted to Urban Settings." Applied and Environmental Microbiology 74, no. 17 (July 18, 2008): 5549–55. http://dx.doi.org/10.1128/aem.00809-08.
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ABSTRACT The common brushtail possum (Trichosurus vulpecula) is one of the most abundant native marsupials in urban Australia, having successfully adapted to utilize anthropogenic resources. The habituation of possums to food and shelter available in human settlements has facilitated interaction with people, pets, and zoo animals, increasing the potential for transmission of zoonotic Cryptosporidium pathogens. This study sought to examine the identity and prevalence of Cryptosporidium species occurring in possums adapted to urban settings compared to possums inhabiting remote woodlands far from urban areas and to characterize the health of the host in response to oocyst shedding. Findings indicated that both populations were shedding oocysts of the same genotype (brushtail possum 1 [BTP1]) that were genetically and morphologically distinct from zoonotic species and genotypes and most closely related to Cryptosporidium species from marsupials. The urban population was shedding an additional five Cryptosporidium isolates that were genetically distinct from BTP1 and formed a sister clade with Cryptosporidium parvum and Cryptosporidium hominis. Possums that were shedding oocysts showed no evidence of pathogenic changes, including elevated levels of white blood cells, diminished body condition (body mass divided by skeletal body length), or reduced nutritional state, suggesting a stable host-parasite relationship typical of Cryptosporidium species that are adapted to the host. Overall, Cryptosporidium occurred with a higher prevalence in possums from urban habitat (11.3%) than in possums from woodland habitat (5.6%); however, the host-specific nature of the genotypes may limit spillover infection in the urban setting. This study determined that the coexistence of possums with sympatric populations of humans, pets, and zoo animals in the urban Australian environment is unlikely to present a threat to public health safety.
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Holland, O. J., P. E. Cowan, D. M. Gleeson, and L. W. Chamley. "413. Genetic diversity of the major histocompatibility complex and response to immunocontraceptives in the brushtail possum." Reproduction, Fertility and Development 20, no. 9 (2008): 93. http://dx.doi.org/10.1071/srb08abs413.
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The brushtail possum (Trichosurus vulpecula) is a major invasive pest in New Zealand. One option for its control is the use of an immunocontraceptive vaccine, a method of fertility control that employs the immune system to attack reproductive cells or proteins. Initial trials of immunocontraceptive vaccines have shown individual variation in immune response. Concerns have been raised that the use of such a vaccine on wild populations could result in selection for possums that remain fertile because of low or no response, and subsequently negate the efficacy of the vaccine. Therefore, it is important to establish the basis of this variation. The major histocompatibility complex (MHC) is an important component of the immune system which influences the nature of immune responses. This study aimed to document genetic variation in MHC loci of New Zealand possums, and investigate whether there was a relationship between MHC haplotypes and individual immune responses to immunocontraceptive vaccines. We used known marsupial (possum, red-necked wallaby, tammar wallaby, opossum) MHC sequences to design PCR primers for possum MHC loci. The variability of these loci was screened in populations of possums from locations throughout New Zealand, and between individuals with known responses to immunocontraceptive vaccines. We identified 71 novel class I and class II MHC alleles and observed significant variation in allele identity and frequency between geographically separate possum populations in New Zealand. Comparisons of MHC haplotype and immunocontraceptive vaccine response showed that some of these alleles differ between high-responding and low-responding possums. The considerable variation we have found in the possum MHC, combined with differences in the occurrence of MHC genes at locations around New Zealand, provide a potential basis for the observed variability of individual possum's responses to immunocontraceptive vaccines.
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Potts, Annie. "Kiwis Against Possums: A Critical Analysis of Anti-Possum Rhetoric in Aotearoa New Zealand." Society & Animals 17, no. 1 (2009): 1–20. http://dx.doi.org/10.1163/156853009x393738.
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AbstractThe history of brushtail possums in New Zealand is bleak. The colonists who forcibly transported possums from their native Australia to New Zealand in the nineteenth century valued them as economic assets, quickly establishing a profitable fur industry. Over the past 80 or so years, however, New Zealand has increasingly scapegoated possums for the unanticipated negative impact their presence has had on the native environment and wildlife. Now this marsupial—blamed and despised—suffers the most miserable of reputations and is extensively targeted as the nation's number one pest. This paper examines anti-possum rhetoric in New Zealand, identifying the operation of several distinct—yet related—discourses negatively situating the possum as (a) an unwanted foreign invader and a threat to what makes New Zealand unique; (b) the subject of revenge and punishment (ergo the deserving recipient of exploitation and commodification); and (c) recognizably “cute, but...” merely a pest and therefore unworthy of compassion. This paper argues that the demonization of possums in New Zealand is overdetermined, extreme, and unhelpfully entangled in notions of patriotism and nationalism.
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O'Keefe, J. S., W. L. Stanislawek, and D. D. Heath. "Pathological studies of wobbly possum disease in New Zealand brushtail possums (Trichosurus vulpecula)." Veterinary Record 141, no. 9 (August 30, 1997): 226–29. http://dx.doi.org/10.1136/vr.141.9.226.
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Harris, PM, DW Dellow, and RB Broadhurst. "Protein and Energy Requirements and Deposition in the Growing Brushtail Possum and Rex Rabbit." Australian Journal of Zoology 33, no. 4 (1985): 425. http://dx.doi.org/10.1071/zo9850425.
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Nitrogen and energy requirements of the growing brushtail possum Trichosurus vulpecula and the Rex rabbit were studied by means of growth, balance and calorimetry techniques in 2 trials. The maintenance requirements of apparently digestible N were estimated from balance as being 358 and 442 mg/kg0.75 daily for the possums and rabbit, respectively. The standard metabolic rates were 200 and 359 kJ/kg0.75 daily; requirements of apparently digestible energy for maintenance were 370 and 480 kJ/kg daily. The possums grew more slowly over the same weight range as the rabbits and deposited a greater proportion of their gain as fat. At the end of both trials the possums had a greater proportion of carcass fat than the rabbits, and both experimental groups of rabbits and possums were fatter than feral possums of the same weight.
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Dix, ID, SE Jolly, LS Bufton, and AI Gardiner. "The potential of electric shock for humane trapping of brushtail possums, Trichosurus vulpecula." Wildlife Research 21, no. 1 (1994): 49. http://dx.doi.org/10.1071/wr9940049.
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The Australian brushtail possum is a major pest in New Zealand, and a device to kill possums in the wild by electric shock has been proposed. This investigation was to determine the best waveform and energy level for an electric device to humanely kill possums. The criterion set was a shock which would cause ventricular fibrillation and result in irreversible unconsciousness within a few minutes. Anaesthetised possums were shocked with sinusoidal alternating currents, direct current bursts and impulse waveforms of varying intensities and durations. An electrocardiogram was used to monitor the cardiac response. Although sinusoidal waveforms of a long duration did disrupt the heartbeat and might result in death, even shocks of very high energy levels did not consistently result in ventricular fibrillation. The use of electricity to trap and kill possums appears unacceptable on humanitarian grounds.
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Clapperton, BK, and LR Matthews. "Trials of electric fencing for restricting movements of common brushtail possums, Trichosurus vulpecula Kerr." Wildlife Research 23, no. 5 (1996): 571. http://dx.doi.org/10.1071/wr9960571.
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The responses of common brushtail possums, Trichosurus vulpecula, to a mesh fence with electrified outrigger wires were examined in a series of trials in an outside enclosure. Possums initially had no hesitation in approaching the fence. Their first contact was usually with the lower hot wire(s). Possums responded to shocks by jumping back, rolling, running away, grooming and head-shaking. Responses depended upon the part of the body contacting the fence. No possums climbed over the electrified fence during a total of 50 trials. Over three or four repeated exposures, eight possums successively took longer to approach the fence and longer to receive the first shock, spent less time in the vicinity of the fence, and received fewer shocks during the first 2 h of the trial. However, over the whole night there was no significant drop in shock frequencies. The addition of a second lower hot wire and an increase in the pulse rate did not prevent possums that had successfully been contained by the fence from breaching the fence when chased towards it repeatedly; 7 of 12 possums were forced over the fence. Possums that had learned to avoid the live fence crossed the fence within 1-7 h after the fence was turned off. Speed and duration of avoidance learning in possums are compared with those in other species. These trials suggest that a combination fence of electrified 'hot wire' and mesh could be useful in reducing contact between possums and farm animals for the control of tuberculosis, reducing possum migration into areas that are free of tuberculosis or of high conservation value, and protecting crops.
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Rouco, C., C. Jewell, K. S. Richardson, N. P. French, B. M. Buddle, and D. M. Tompkins. "Brushtail possum (Trichosurus vulpecula) social interactions and their implications for bovine tuberculosis epidemiology." Behaviour 155, no. 7-9 (2018): 621–37. http://dx.doi.org/10.1163/1568539x-00003512.
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Abstract The brushtail possum is the main reservoir of bovine tuberculosis in New Zealand. Disease prevalence is generally higher in males than in females. This has conventionally been assumed due to greater infection rates of males, but recent work has raised the hypothesis that it may instead be driven by survival differences. With bovine tuberculosis transmission among possums most likely occurring between individuals in close proximity, here we analyse social networks built on data from wild possums collared with contact loggers inhabiting a native New Zealand forest, to investigate whether there is mechanistic support for higher male infection rates. Our results revealed that adult female possums were generally just as connected with adult male possums as other adult males are, with male–female connection patterns not being significantly different. This result suggest that the new ‘survivorship’ hypothesis for the sex bias is more likely than the conventional ‘infection rate’ hypothesis.
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Lohr, Cheryl A., Harriet Mills, Helen Robertson, and Roberta Bencini. "Deslorelin implants control fertility in urban brushtail possums (Trichosurus vulpecula) without negatively influencing their body-condition index." Wildlife Research 36, no. 4 (2009): 324. http://dx.doi.org/10.1071/wr08050.
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Wild brushtail possums (Trichosurus vulpecula) occur in large numbers in the grounds of Perth Zoo, Western Australia. These possums are a problem because they consume feed the zoo buys for its captive animals, damage seedlings and trees and many need to be treated for injuries sustained during fights with conspecifics. A contraceptive implant, which contains the gonadotrophin releasing hormone (GnRH) agonist deslorelin, could be a potential method of managing this population. We tested the efficacy of the implant and its impact on the body-condition index of treated possums with Kaplan–Meier analysis and a mixed model with residual maximum likelihood. We implanted 60 female possums with deslorelin and monitored reproductive success of treated and untreated possums for the following 18 months. At the conclusion of the study, 80% of 20 treated females recaptured had shown no evidence of breeding activity, giving an average minimum duration of effective contraception of 381 days. The implant did not have a negative impact on the body-condition index of treated possums during the course of the study. Our results suggest that deslorelin implants could be an effective management tool for brushtail possums at Perth Zoo and in other urban environments.
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Morgan, DR, G. Morriss, and GJ Hickling. "Induced 1080 Bait-Shyness in Captive Brushtail Possums and Implications for Management." Wildlife Research 23, no. 2 (1996): 207. http://dx.doi.org/10.1071/wr9960207.
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The probable cause of possums (Trichosurus vulpecula) becoming 'shy' towards 1080 [sodium fluoroacetate] bait, a growing problem in the control of this pest, was determined. Possums captured from North Canterbury, New Zealand, (n = 131) were offered sublethal baits (1 or 2.5 g) followed by lethal (6 g) baits 2 days later. Most possums became bait shy and the proportion becoming shy appeared to be related to the size of the initial sublethal dose. Most of a group of survivors retested after 3 months with toxic pellets were still shy. Shyness was not overcome by changing to a different mask (orange flavour, as opposed to cinnamon flavour) or toxin (brodifacoum), but changing to both a different bait base (carrot) and mask (orange) resulted in most shy possums eating a lethal quantity of bait. Possums therefore appeared to learn to recognise the bait base as the cue for avoiding poisoning. More shy possums than naive possums rejected non-dyed, non-masked, non-toxic pellets, confirming that shy possums recognised the bait base. Green dye appears to act as a secondary cue for avoiding pellets as a higher percentage of 'shy' possums than naive possums rejected dyed baits.
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Arthur, A., D. Ramsey, and M. Efford. "Impact of bovine tuberculosis on a population of brushtail possums (Trichosurus vulpecula Kerr) in the Orongorongo Valley, New Zealand." Wildlife Research 31, no. 4 (2004): 389. http://dx.doi.org/10.1071/wr03097.
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Brushtail possums are the main wildlife vectors of bovine tuberculosis (Tb) in New Zealand. Possum–Tb models form the basis of possum control aimed at eradicating the disease, and yet competing models show different behaviour, and are highly sensitive to parameters about which there is considerable uncertainty. One area of great uncertainty is the impact of the disease on possum populations. We investigated the impact of Tb on a local population of brushtail possums in the Orongorongo Valley, Wellington. Bovine Tb was first detected in 1997 at one site within an intensively studied population, but has not been detected in another intensively studied population 3 km away since the early 1980s. Using a Before-After-Control-Impact (BACI) analysis, detection of Tb coincided with a 42% (95% CI = 23–56%) reduction in the odds of apparent yearly survival of a possum >17 months of age, i.e. a decrease in yearly survival from 0.85 to 0.77 in 'good' years, and a decrease from 0.71 to 0.60 in 'bad' years. This suggests that Tb had a significant impact on overall survival. However, there was no impact on local population density in September each year due to compensatory recruitment.
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Pattabiraman, Nimeshika, Mary Morgan-Richards, Ralph Powlesland, and Steven A. Trewick. "Unrestricted gene flow between two subspecies of translocated brushtail possums (Trichosurus vulpecula) in Aotearoa New Zealand." Biological Invasions 24, no. 1 (September 29, 2021): 247–60. http://dx.doi.org/10.1007/s10530-021-02635-z.
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AbstractTwo lineages of brushtail possums (Trichosurus vulpecula) were historically introduced to Aotearoa New Zealand, and these two subspecies have different phenotypic forms. Despite over 100 years of potential interbreeding, they appear to retain morphological differences, which may indicate reproductive isolation. We examined this using population samples from a confined landscape and scored each specimen for phenotype using a number of fur colour traits. This resulted in a bimodal trait distribution expected for segregated grey and black lineages. We also sought evidence for genetic partitioning based on spatial and temporal effects. Genetic structure and rates of genetic mixing were determined using seven neutral, species-specific nuclear microsatellite markers and mitochondrial DNA control region sequence. Genotype analyses indicated high levels of variation and mtDNA sequences formed two major haplogroups. Pairwise tests for population differentiation of these markers found no evidence of subdivision, indicating that these brushtail possums behave as a single randomly mating unit. Despite maintenance of two main colour phenotypes with relatively few intermediates, previous inference of assortative mating and anecdotes of distinct races, our data indicate that New Zealand brushtail possums can freely interbreed, and that in some locations they have formed completely mixed populations where neutral genetic markers are unrelated to phenotype. This has implications for effective pest management towards eradication.
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Coleman, JD. "Distribution, Prevalence, and Epidemiology of Bovine Tuberculosis in Brushtail Possums, Trichosurus-Vulpecula, in the Hohonu Range, New-Zealand." Wildlife Research 15, no. 6 (1988): 651. http://dx.doi.org/10.1071/wr9880651.
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Over a 12-month period, 1467 brushtail possums were trapped and then killed or were poisoned along sampling lines on pasture-forest margins and in nearby forest. An additional 334 possums were shot on adjacent farm land. All possums were necropsied, and 141 had macroscopic lesions typical of bovine tuberculosis. Infected possums occurred most commonly in small foci of 2-5 individuals along pasture-forest margins; the furthest from pasture that an infected animal was taken was 4050 m. Lesions occurred in possums of all ages in both sexes, but disease prevalence was highest in immature males and during autumn and winter. Infected possums bred as successfully as non-infected individuals, but were of lighter body weight. Macroscopic lesions occurred in a wide range of visceral and lymph node sites. Lesions were most common in the lungs and axillary nodes, and occasionally formed open sinuses from which infected possums could shed M. bovis readily, and thus were likely to be highly infective. Evidence suggested that disease transmission occurs most frequently on pasture-forest margins, where possum numbers are greatest and possum and cattle mix most freely.
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Baillie, Gregory J., and Richard J. Wilkins. "Endogenous Type D Retrovirus in a Marsupial, the Common Brushtail Possum (Trichosurus vulpecula)." Journal of Virology 75, no. 5 (March 1, 2001): 2499–507. http://dx.doi.org/10.1128/jvi.75.5.2499-2507.2001.
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ABSTRACT We have sequenced and characterized an endogenous type D retrovirus, which we have named TvERV(D), from the genome of an Australian marsupial, the common brushtail possum (Trichosurus vulpecula). Intact TvERV(D) gag, pro, pol, andenv open reading frames were detected in the possum genome. TvERV(D) was classified as a type D retrovirus, most closely related to those of Old World monkeys, New World monkeys, and mice, based on phylogenetic analyses and genetic organization. Approximately 30 TvERV(D) proviruses are present in the genomes of possums, as detected by Southern hybridization. However, variability in fragment patterns between possums was observed and suggests recent (or ongoing) retrotranspositional activity.
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Carman, RM, and KD Klika. "Partially Racemic Compounds as Brushtail Possum Urinary Metabolites." Australian Journal of Chemistry 45, no. 4 (1992): 651. http://dx.doi.org/10.1071/ch9920651.
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The hydroxycineole (2) and cineolic acid (3) obtained as urinary metabolites from the brushtail possum (Trichosurus vulpecula) after the ingestion of l,8-cineole (1), are partial racemates. The compounds have been examined by gas chromatographic analysis over chiral stationary phases, and by the synthesis of optically pure enantiomers. Female possums show different enantiomeric ratios from males. Possible advantages to the animal in the use of a partial racemate as a pheromone are discussed.
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Cope, Holly R., Tamara Keeley, Joy Keong, Daniel Smith, Fabiola R. O. Silva, Clare McArthur, Koa N. Webster, Valentina S. A. Mella, and Catherine A. Herbert. "Validation of an Enzyme Immunoassay to Measure Faecal Glucocorticoid Metabolites in Common Brushtail Possums (Trichosurus vulpecula) to Evaluate Responses to Rehabilitation." Animals 12, no. 13 (June 24, 2022): 1627. http://dx.doi.org/10.3390/ani12131627.
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Volunteer wildlife rehabilitators rescue and rehabilitate thousands of native animals every year in Australia. However, there is little known about how exposure to novel stimuli during rehabilitation could affect the physiology of wildlife. We investigated this question in a species that commonly enters rehabilitation, the common brushtail possum (Trichosurus vulpecula). We evaluated five enzyme immunoassays (EIA) to determine the most suitable for measuring faecal glucocorticoid metabolites (FGM) as a proxy for evaluating the response of brushtail possums to potential stressors during rehabilitation. An adrenocorticotrophin hormone (ACTH) challenge was conducted on wild-caught possums to determine the best-performing EIA based on the successful detection of FGM peaks in at least two of three possums. While a number of assays met these criteria, the 11-oxoaetiocholanolone (abbreviation: 72a) EIA was selected as it had the largest amplitude of change in response to the ACTH challenge. This assay was then used to measure FGM concentrations in 20 possums during rehabilitation. There was high variation in baseline FGM concentrations and response to captivity between possums. Significant changes in FGM levels were detected in most possums during captivity, but were not reliably associated with potentially stressful events that were identified by rehabilitators. The probability of an FGM peak occurring within five days of a potentially stressful event was about 50%, regardless of the type of event. Our study has demonstrated that injured and orphaned possums show changes in FGMs during captivity and rehabilitation and has identified events that can induce a physiological response in some individuals. We recommend that research now focus on the relationship between these responses during rehabilitation and pre- and post-release survival.
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Moss, Zane N., Cheryl E. O'Connor, and Graham J. Hickling. "Implications of prefeeding for the development of bait aversions in brushtail possums (Trichosurus vulpecula)." Wildlife Research 25, no. 2 (1998): 133. http://dx.doi.org/10.1071/wr97018.
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Development of aversions, or learned ‘bait-shyness’, in frequently poisoned possum (Trichosurus vulpecula) populations is becoming increasingly detrimental to the efficacy of pest-control operations in New Zealand. This experiment aimed to identify the effects of prefeeding, a common management procedure, on the subsequent development of aversions in possums. Wild possums (n = 96) were captured and acclimatised, then allocated to one of three treatments groups that for seven days received either (i) no prefeed, (ii) plain RS5 cereal baits, or (iii) green-dyed and cinnamon-lured RS5 cereal baits. The possums were then offered a standard green-dyed and cinnamon-lured RS5 bait that contained a sublethal dose (0.4 mg kg-1) of the toxin sodium monofluoroacetate (1080). The possums were tested for development of an aversion towards a toxic RS5 1080 bait, a prefeed bait, and a prefeed bait containing an alternative toxin, brodifacoum. Most (96%) of the non-prefed possums became averse to the 1080 bait after two exposures, compared with only 55% and 9% of the two prefed groups. Similarly, 90% and 92% of the non-prefed possums were averse to prefeed and brodifacoum baits, respectively, compared with 8% and 14% of the prefed possums. This suggests that pest managers can reduce the risk of ‘bait shyness’ by prefeeding. A further advantage of prefeeding is that if poison shyness develops, use of an alternative toxin such as brodifacoum in the original bait base may still be successful.
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Cowan, Phil, and Guy Forrester. "Behavioural responses of brushtail possums to live trapping and implications for trap-catch correction." Wildlife Research 39, no. 4 (2012): 343. http://dx.doi.org/10.1071/wr11127.
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Context The behavioural response of animals to repeated trapping has implications for correction of population and monitoring indices that use catch per unit effort. Failure to account for sprung traps introduces biases into estimates of relative abundance. The time when animals get caught in live traps is often ignored, but it can provide important information about temporal movement patterns relevant to this issue. Aims We assessed changes in the behaviour of brushtail possums (Trichosurus vulpecula), a nocturnal marsupial, in response to repeated trapping and evaluated the potential benefit of correcting a commonly used index of abundance by using time-of-capture information. Methods Possums were live-trapped for three nights each month over a 20-month period in baited cage traps in a 6-ha area of native lowland forest in the southern North Island, New Zealand. Trapped possums were individually identified on first capture. Timing devices were attached to the traps to measure how long after sunset traps were sprung and how that time related to the duration of the trap-night (sunset to sunrise). Key results Possums were trapped, on average, ~1.25 h after sunset. Traps triggered other than by possums were sprung on average 1–2 h later. Possums caught on the first night of a trapping session were caught significantly earlier than those caught on subsequent nights. Previous capture influenced the time of subsequent capture in a trapping session in complex ways, and recapture times were generally earlier than times of first capture. Possums were captured, on average, after 11% of the duration of a trap-night and traps were triggered by animals other than possums, on average, after 22% of the duration of a trap-night. Conclusions The data on time of capture of possums and triggering of sprung traps suggested a need to alter the commonly used correction factor for population indices for possums, because, on average, traps were sprung for significantly more of each trapping interval (i.e. trap-night) than the half a trap-night assumed in the correction factor. Implications Better understanding of possum foraging behaviour is a key to more effective control using traps. In that context, more research is needed to understand the reasons for individual differences in trappability. Although it is theoretically desirable to account for sprung traps when trapping is used to index populations, to reduce biases in estimates of relative abundance, correction of the standardised residual trap-catch index for possums is probably unimportant in practical terms, because most possum control reduces numbers to levels (2–5% trap catch) at which correction of the index is unimportant. The principal exception to this is likely to be when there is a high level of non-target interference from rodents.
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Munks, SA, R. Corkrey, and WJ Foley. "Characteristics of Arboreal Marsupial Habitat in the Semi-Arid Woodlands of Northern Queensland." Wildlife Research 23, no. 2 (1996): 185. http://dx.doi.org/10.1071/wr9960185.
Full textAbstract:
The distribution of the koala (Phascolarctos cinereus) and the common brushtail possum (Trichosurus vulpecula) within the Prairie-Torrens Creek Alluvials province of the Desert Upland region of north-western Queensland was examined. The optimum habitat for each species as indicated by the occurrence of faecal pellet groups was found to be that associated with creek-lines. However, other land types were also used by each species to varying degrees. The relationship between various habitat variables and pellet group counts was investigated using Multiple regression and a Generalised linear model. Proximity to creek-bed, total basal area of trees, species richness and Acacia basal area (negative) best explained the occurrence of koalas. Proximity to creek-bed, Acacia basal area (negative), total basal area of trees, and available water (negative) best explained the occurrence of brushtail possums. In contrast to studies of arboreal species in the moist-south-eastern forests of Australia no relationship was found between foliar nutrient concentrations and the occurrence of koalas or brushtail possums. However, a significant relationship was found between leaf water concentration and the occurrence of koalas. It is suggested that water availability is the paramount factor defining preferred arboreal habitat in arid and semi-arid woodlands.
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Littin, K. E., C. E. O'Connor, N. G. Gregory, D. J. Mellor, and C. T. Eason. "Behaviour, coagulopathy and pathology of brushtail possums (Trichosurus vulpecula) poisoned with brodifacoum." Wildlife Research 29, no. 3 (2002): 259. http://dx.doi.org/10.1071/wr01068.
Full textAbstract:
Brodifacoum is a second-generation anticoagulant rodenticide used widely for controlling brushtail possums (Trichosurus vulpecula) in New Zealand. We determined its toxic effects on possums to make inferences about the welfare of brodifacoum-poisoned possums. Caged possums were fed a lethal dose of brodifacoum in cereal baits then either bled and killed 4, 8, 12, 16 or 20 days later to establish the effects on blood-clotting, or observed for behavioural changes until death. Blood-clotting time was prolonged 8 days after possums first began ingesting brodifacoum and time to death was 20.7 ± 1.7 days (mean ± s.e.m.). Clinical signs of poisoning, including changed appearance, pale noses and external bleeding, appeared from 14 days after initial poisoning (7 days before death). Possums gradually became inactive and lethargic, typically crouching and lying in abnormal postures for 6 days before death. Feed intake reduced concurrently, resulting in significant loss of body weight of 5.9 ± 2.1%. All possums had widespread, usually severe, haemorrhaging. Internal haemorrhages first appeared in all possums 8 days after initial ingestion. These haemorrhages, and consequent blood loss, may cause distress, pain, weakness or sickness, and this is supported by evidence from humans and other animals. Reduced feed intake, inactivity, lethargy and the display of abnormal postures suggest that possums do experience distress for at least 6 days before death.
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Hufschmid, J., K. A. Handasyde, and I. Beveridge. "The role of host and environmental factors in the epidemiology of rumpwear in brushtail possums." Australian Journal of Zoology 58, no. 4 (2010): 250. http://dx.doi.org/10.1071/zo10030.
Full textAbstract:
Rumpwear is a common, but poorly defined and understood disease of brushtail possums (Trichosurus spp.) in Australia and New Zealand, resulting in varying degrees of fur loss. Populations of Trichosurus cunninghami (mountain brushtail possum) and T. vulpecula (common brushtail possum) were studied over two years at Boho South (Victoria), to describe the disease, investigate its prevalence and explore its epidemiology. The main type of lesion observed was coat damage in the lumbo-sacral region, and increased severity of rumpwear was related to decreased coat length and increased hair breakage. Significant skin lesions were rare and hair breakage patterns suggested mechanical damage. Rumpwear was very prevalent in both T. cunninghami and T. vulpecula, but very severe rumpwear was rare. There was no true seasonal pattern to the prevalence of rumpwear in T. cunninghami and sex and habitat did not affect prevalence or severity. Prevalence and severity of rumpwear did, however, increase with age. There were no significant relationships between the number of previous captures or body condition index with rumpwear.
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Cowan, PE, DK Blackmore, and RB Marshall. "Leptospiral Infection in Common Brushtail Possums (Trichosurus Vulpecula) From Lowland Podocarp/Mixed Hardwood Forest in New Zealand." Wildlife Research 18, no. 6 (1991): 719. http://dx.doi.org/10.1071/wr9910719.
Full textAbstract:
A survey of 261 common brushtail possums (Trichosurus vulpecula) from New Zealand lowland podocarp/mixed hardwood forest showed 34% of possums with antibodies to Leptospira interrogans serovar balcanica, 35% with antibodies to serovar hardjo, and isolation of balcanica leptospires from 23% of kidney cultures. One possum showed a titre to serovar ballum, leptospires of which were subsequently isolated in culture. Seroprevalences and isolation rates were similar in mature males and females, and increased with age. Sexually immature possums were rarely infected, but recently matured animals had significant rates of infection. Seroprevalence was elevated during the breeding season, suggesting that primary infections were generally acquired in association with sexual maturity and mating. There was no significant association between prevalence of infection and genotype, based on 8 polymorphic proteins. Infection had no significant effect on various indices of possum condition. In their response to infection, possums displayed characteristics typical of a maintenance host.
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Richardson, K. S., C. Rouco, C. Jewell, N. P. French, B. M. Buddle, and D. M. Tompkins. "Investigating brushtail possum (Trichosurus vulpecula) home-range size determinants in a New Zealand native forest." Wildlife Research 44, no. 4 (2017): 316. http://dx.doi.org/10.1071/wr16215.
Full textAbstract:
Context The Australian brushtail possums (Trichosurus vulpecula) introduction to New Zealand has exacted a heavy toll on native biodiversity and presented the country with its greatest wildlife reservoir host for bovine tuberculosis (TB). Management efforts to control both possums and TB have been ongoing for decades, and the biology of possums has been studied extensively in Australia and New Zealand over the past 50 years; however, we still do not have a clear understanding of its home-range dynamics. Aims To investigate determinants of home range size by using a uniquely large dataset in the Orongorongo Valley, a highly monitored research area in New Zealand and compare our findings with those of other studies. Methods Possum density was estimated, for subpopulations on four 13-ha cage-trap grids, by the spatially explicit capture–mark–recapture analysis of trapping data from 10 consecutive months. Home ranges were estimated from trap locations using a 100% minimum convex polygon (MCP) method for 348 individuals and analysed with respect to grid, age and sex. Key results Mean (standard error) possum density, estimated as 4.87 (0.19), 6.92 (0.29), 4.08 (0.21) and 4.20 (0.19) ha–1 for the four grids, was significantly negatively correlated with mean MCP home-range size. Grid, age, and the interaction of age and sex were significantly related to home-range size. Older possums had larger home ranges than did younger possums. When ‘juvenile cohort’ and ‘adult cohort’ data were analysed separately, to investigate the significant interaction, males in the ‘adult cohort’ had significantly larger home ranges than did females, with the grid effect still being apparent, whereas neither sex nor grid effects were significant for the ‘juvenile cohort’. Conclusions Our findings indicate that, in addition to density, age and sex are likely to be consistent determinants of possum home-range size, but their influences may be masked in some studies by the complexity of wild-population dynamics. Implications Our findings have strong implications regarding both disease transmission among possums and possum management. The fact that adult males occupy larger home ranges and the understanding that possum home range increases as population density decreases are an indication that males may be the primary drivers of disease transmission in possum populations. The understanding that possum home range increases as population density decreases could be a direct reflection of the ability of TB to persist in the wild that counteracts current management procedures. If individuals, and particularly males, infected with TB can withstand control measures, their ensuing home-range expansion will result in possible bacteria spread in both the expanded area of habitation and new individuals becoming subjected to infection (both immigrant possums and other control survivors). Therefore, managers should consider potential approaches for luring possum males in control operations.