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Fear may elicit behavioural and physiological responses in animals. We conducted a pilot study aiming to reduce bird nest predation in Tasmania by the introduced Sugar Glider (Petaurus breviceps) by broadcasting calls of predatory owls. We designed a solar‐powered, automated weatherproof stereo for long‐term call broadcast in a forest environment. This device may have useful applications in other environments where long‐term call broadcast is required in remote field conditions. Call broadcast did not reduce the likelihood of Sugar Glider nest predation on either active bird nests or artificial nests baited with farmed quail eggs. If we elicited fear in Sugar Glider individuals with call broadcast, this fear did not result in behavioural changes that could be exploited to achieve the conservation objective of lower predation.

Aim Range expansions facilitated by humans or in response to local biotic or abiotic stressors provide the opportunity for species to occupy novel environments. Classifying the status of newly expanded populations can be difficult, particularly when the timing and nature of the range expansion are unclear. Should native species in new habitats be considered invasive pests or actively conserved? Here, we present an analytical framework applied to an Australian marsupial, the sugar glider (Petaurus breviceps), a species that preys upon on an endangered parrot in Tasmania, and whose provenance was uncertain. Location Tasmania, Australia. Methods We conducted an extensive search of historical records for sugar glider occurrences in Tasmania. Source material included museum collection data, early European expedition logs, community observation records, and peer‐reviewed and grey literature. To determine the provenance of the Tasmanian population, we sequenced two mitochondrial genes and one nuclear gene in Tasmanian animals (n = 27) and in individuals across the species' native range. We then estimated divergence times between Tasmania and southern Australian populations using phylogenetic and Bayesian analyses. Results We found no historical evidence of sugar gliders occurring in Tasmania prior to 1835. All Tasmanian individuals (n = 27) were genetically identical at the three genes surveyed here with those individuals being 0.125% divergent from individuals from a population in Victoria. Bayesian analysis of divergence between Tasmanian individuals and southern Australian individuals suggested a recent introduction of sugar gliders into Tasmania from southern Australia. Main conclusions Molecular and historical data demonstrate that Tasmanian sugar gliders are a recent, post‐European, anthropogenic introduction from mainland Victoria. This result has implications for the management of the species in relation to their impact on an endangered parrot. The analytical framework outlined here can assist environmental managers with the complex task of assessing the status of recently expanded or introduced native species.

Gliding mammals are sensitive to habitat fragmentation that produces canopy gaps beyond their gliding capability. Specific structures (canopy-bridges and glide poles) are now commonly installed in large road construction projects to enable road crossing by threatened gliding mammals. However, these structures are being installed with limited understanding of how their design features influence their use. We conducted field testing of several design features (horizontal glide launch-beams at the top of poles; rope size and complexity in rope-bridges) using free-ranging gliding mammals, and scaled-down structures at two locations. Our aim was to identify preferred features to optimise structure use. This may confirm current designs or identify the need for refinement. We found that squirrel gliders (Petaurus norfolcensis) and sugar gliders (Petaurus breviceps) preferred a forward-pointing over a sideways-pointing glide beam. A single-rope rope-bridge was favoured over a mesh rope-bridge by sugar gliders but not squirrel gliders. No preference was shown by either species between mesh or ladder-style rope-bridges that differed in rope strand spacing. Large, permanently installed ladder or mesh rope-bridges commonly have single ropes connecting them to the adjacent forest. We investigated the use of a permanently installed 50-m long single-rope rope-bridge. Infra-red camera monitoring over 366 nights detected squirrel gliders on this bridge on 172 nights, common ringtail possums (Pseudocheirus peregrinus) on 144 nights and common brushtail possums (Trichosurus vulpecula) on 120 nights. This confirms acceptance of the single rope by a range of species and provides confidence in installing rope-bridges that may vary in rope size and complexity.

Millions of dollars are spent on wildlife crossing structures intended to reduce the barrier effects of roads on wildlife. However, we know little about the degree to which these structures facilitate dispersal and gene flow. Our study incorporates two elements that are rarely used in the evaluation of wildlife crossing structures: an experimental design including a before and after comparison, and the use of genetic techniques to demonstrate effects on gene flow at both population and individual levels. We evaluated the effect of wildlife crossing structures (canopy bridges and glider poles) on a gliding mammal, the squirrel glider (Petaurus norfolcensis). We genotyped 399 individuals at eight microsatellite markers to analyse population structure, first-generation migrants and parentage relationships. We found that the freeway was not a complete genetic barrier, with a strong effect evident at only one site. We hypothesise that the presence of corridors alongside the freeway and throughout the surrounding landscape facilitated circuitous detours for squirrel gliders. Installing a crossing structure at the location with a strong barrier effect restored gene flow within just 5 years of mitigation. Synthesis and applications. Our study highlights the importance of using genetic techniques not just to evaluate the success of road-crossing structures for wildlife, but also to guide their placement within the landscape. Managers wishing to reduce the effects of linear infrastructure on squirrel gliders and other arboreal mammals should aim to preserve and enhance vegetation along roadsides and within centre medians, as well as mitigate large gaps by implementing wildlife crossing structures.

Nest boxes are frequently used in conservation programs for tree-cavity dependent wildlife. There is growing concern that the poor insulation properties of nest boxes may produce an ecological trap, because species may require microclimates less extreme or less variable than those experienced inside nest boxes. I investigated the fitness consequences of nest box use in a non-flying mammal. Fifty-two of 104 squirrel gliders (Petaurus norfolcensis) trapped over a 3-year period used nest boxes. Population modelling of the capture data revealed that the probability of apparent survival increased with increasing nest box use. There was no difference in breeding frequency between females that used or did not use nest boxes. There was no evidence that offspring development was hindered within nest boxes. These findings may arise because: (1) gliders could access tree hollows during extreme temperatures, (2) ambient temperatures were mild during the study, (3) gliders construct leaf nests which insulate against low temperatures in winter, and (4) gliders breed between autumn and spring when temperatures are relatively benign. The estimate of annual survival of animals using nest boxes (0.60), was equivalent to estimates at locations where squirrel gliders were either reliant on nest boxes (0.54) or on tree cavities (0.55) for shelter. Studies such as this need to be conducted on a range of species across a range of locations to better understand the influence of nest box use on non-flying mammals.

Summary Southern Squirrel Glider (Petaurus norfolcensis) populations are genetically distinct and generally found in the agricultural landscapes inland of Australia's Great Dividing Range. These populations are considered to be under greater threat of extinction than northern, coastal populations and face a unique set of environmental conditions and conservation challenges. For these reasons, we suggest that southern populations qualify as a separate evolutionarily significant unit to those from the northern, coastal segment of the range and should be managed separately. We summarize the species’ ecology specific to southern populations and relevant to management. We conduct a basic SWOT (strengths, weaknesses, opportunities, threats) analysis to highlight potential future management directions. From our review of new and existing ecological data and SWOT analysis, we outline ten points of action important for securing the future of southern Squirrel Glider populations.

Tree-cavity-dependent wildlife faces future shortages of cavities due to a decline in the abundance of large, old trees in many parts of the world. Nest boxes are proposed as a tool to restore habitat value but evidence of their effectiveness for arboreal mammals remains equivocal. This may arise from a poor understanding of design preferences. We conducted investigations in two landscapes in eastern Australia to determine whether species show a preference for specific designs. We observed a preference by some mammal species for particular designs (33–78% occupied/used), suggesting that design refinement can improve the frequency with which nest boxes are used. Although feral species may out-compete target species for nest boxes, we did not observe this. We recorded feral honeybees (Apis mellifera) in 6–9% of nest boxes but they did not remain, and many occupied boxes were later used by mammals. The introduced common myna bird (Acridotheres tristis) was prevalent in one landscape, but competition for nest boxes was localized. For nest boxes to be an effective habitat restoration tool, they must be able to be occupied over long periods of time. We investigated this for the squirrel glider (Petaurus norfolcensis), an arboreal marsupial threatened through part of its geographic range. Squirrel gliders occupied and bred within nest boxes (100% used) at two locations continuously over a 10-year period with minimal nest box maintenance. Individuals occupied boxes for up to 7 years. This confirms that targeted nest box programs can be an effective restoration tool for cavity-dependent arboreal mammals.

Summary Listeria monocytogenes is a Gram-positive, facultative anaerobic, rod-shaped bacterium that can infect and cause disease in many species. In this case report, we describe a case of L. monocytogenes infection causing sepsis in a sugar glider (Petaurus breviceps). The sugar glider consumed a varied diet consisting of human food items, including cantaloupe. A nationwide outbreak of L. monocytogenes foodborne illness associated with cantaloupes occurred simultaneously with this incident case. In this case, the bacterial strains from the outbreak and glider were genetically distinct. Although rare, veterinarians should be aware of the emergence of foodborne pathogens' ability to infect exotic animals residing in domestic environments.

Aim Introduced predators are a global driver of species decline, but their impact on highly mobile species is poorly understood. We report the severe impact of a previously undocumented introduced predator on the endangered, migratory swift parrot (Lathamus discolor). Sugar gliders (Petaurus breviceps), a supposedly benign introduced species, were detected acting as a major opportunistic predator of cavity-nesting birds. We assessed the intensity and geographical extent of sugar glider predation and investigated whether habitat loss exacerbated predation risk to swift parrots. Location Tasmania, Australia. Methods We monitored nests of swift parrots for 3 years with motion-activated cameras. We used bioclimatic modelling to predict the potential distribution of introduced sugar gliders across the study area and assessed the predation risk to swift parrots and other threatened birds in the region using nest-survival analysis. Results Daily survival of nests in areas where sugar gliders occurred was mean 0.97, which equated to a true likelihood of 0.17 for a nest to survive the 60-day nesting period. No nests failed on an offshore island where sugar gliders were shown to be absent. Most cases (83.3%) of glider predation resulted in the death of the adult female parrot. On the Tasmanian mainland, there was a positive relationship between nest survival and increasing mature forest cover at the landscape scale. Main conclusions Predation risk varied dramatically across the breeding range of swift parrots, depending on the presence of sugar gliders. Offshore islands are an important refuge for swift parrots because sugar gliders are absent. However, islands are vulnerable, and our bioclimatic model shows that they are bioclimatically suitable for sugar gliders. Synergistic interactions between predation and habitat loss combine with low breeding-site philopatry to expose swift parrots to dramatic variation in predation risk depending on nesting location.

Habitat corridors that facilitate functional connectivity are a fundamental component of wildlife conservation in fragmented landscapes. However, the landscape matrix separating suitable habitat is not uniformly impermeable to movement and management to increase matrix permeability could be an alternative means to maintain connectivity. Gliding mammals are particularly sensitive to fragmentation because their movements are constrained by glide distance thresholds. Populations of gliders in cities are at risk of being isolated by increasing habitat loss and urban development, yet little is known about how the urban matrix affects glider movement. Here we investigate how the level of urbanization and tree cover in the matrix influence matrix permeability to sugar gliders (Petaurus breviceps) within suburban forest reserves. Twenty-two sugar gliders were radio-tracked over winter and summer at four reserves. Boundary crossing behaviour was measured as the number of times each glider crossed into the matrix, and matrix permeability was determined as the maximum distance travelled by gliders into the matrix. The majority of gliders (81%) were located in the matrix at least once, and rates of boundary crossing were consistent across urbanization and tree cover levels. Matrix permeability was negatively affected by matrix urbanization, but not by matrix tree cover, and no interaction effects were found. Although distances travelled by gliders into the matrix did not exceed 180m, they were comparable with typical movement distances by gliders in reserves. Our results demonstrate that the urban matrix can provide suitable habitat for gliding mammals to move and forage, but that increased urbanization may inhibit glider use of the matrix irrespective of tree cover. This finding has implications for conservation planning and suggests that structurally connected areas may not be used if movement behaviour is inhibited. Conversely, management of matrix permeability could be used to maintain connectivity without needing to construct physical corridors. © 2012 Ecological Society of Australia.

Tree-dwelling mammals may be vulnerable to road mortality if forced to cross canopy gaps on the ground. This group of mammals has received scant attention worldwide despite major road projects potentially causing severe fragmentation to their habitat. Gliding mammals may be enabled to cross road gaps that exceed their gliding capability by the installation of tall wooden poles to act as “stepping stones.” We investigated whether such glide poles installed across two land-bridges in eastern Australia could restore landscape connectivity for small gliding petaurid marsupials. Hair-traps revealed repeated use of all poles at both locations over periods of 1–3 years. Camera traps at one site suggest a crossing frequency on the poles by the squirrel glider (Petaurus norfolcensis) of once every 3.8 nights. Radio-tracked animals did not glide directly over the road but instead used the poles to cross on the bridge. Hair-traps and camera traps installed within the middle of two reference land-bridges that lacked glide poles failed to detect crossings by gliding mammals despite their presence in adjacent forest. These observations suggest that glide poles can facilitate road crossing and thereby restore habitat connectivity for gliding mammals. This lends support to the notion that glide poles have the potential to mitigate road-induced habitat fragmentation for gliding mammals worldwide.

Conservation biology and landscape ecology are increasingly concerned with the effects of urbanization on wildlife, including the influences of habitat edges. This is particularly important in landscapes where a restriction on species home-range movements may reduce an animal's ability to access habitat resources, which ultimately reduces population viability. Despite this, there is limited information available on the movement behavior of wildlife at forest edges adjoining urban areas. We addressed this by radiotracking 30 squirrel gliders Petaurus norfolcensis in forest interiors and near road and residential edges in the fragmented urban landscape of south-east Queensland, Australia. An assessment of fixed-kernel (FK100% and FK50%) and minimum convex polygon (MCP100%) methods revealed that FK provided the most reliable home-range estimates. We applied a general linear model to test the influence of season, age and sex relative to habitat type (forest interiors, road edge, residential edge) on squirrel glider home-range size (FK95% & FK50%). We found that squirrel gliders living in interior habitats had significantly larger home ranges (7.07 ha±0.43) than individuals living near roads (3.79 ha±0.22) and residential areas (3.40 ha±0.26). Similarly, home-range core areas (FK50%) were significantly larger in forest interiors (1.49±0.13 ha) than near road (0.78±0.07 ha) and residential edges (0.70±0.08 ha). We also found that squirrel gliders regularly cross narrow roads up to 20 m wide and with a tree gap up to 15 m to access adjacent vegetation, and are willing to utilize foraging resources in residential backyards. Changes in squirrel glider home ranges near edges identified in this study have implications for understanding how this species responds to urban edges, and we highlight important areas for future edge-related studies to correctly inform conservation and management.

Urban landscapes often expose wildlife populations to enhanced edge effects where the biotic and abiotic attributes of native ecosystems have been significantly altered. While some species may respond favourably to edges, there are likely to be varying negative consequences for many forest-dependent species. In particular, marsupial gliders are influenced by changes in forest composition and structure near edges due to highly specific feeding and nesting requirements, and a high reliance on tree cover to traverse a landscape. We addressed this problem using the squirrel glider (Petaurus norfolcensis) in the fragmented urban landscape of southeast Queensland, Australia. Analysis of variance was applied to determine differences in habitat resources and structure in relation to glider presence and trap success rates in forest fragment interiors compared with road (minor & major) and residential edge habitats. We postulate that an increased presence of squirrel gliders in sites adjacent to minor road and residential edges may be due to the availability of additional resources and/or varying dispersal opportunities. Conversely, forest fragment interiors contain a higher abundance of nest hollows and large trees, together with a greater floristic species richness providing more reliable seasonal foraging sources, which may explain the greater trap success rates of squirrel gliders in these sites. We conclude that while forest fragment interiors provide habitat suitable for year-round use by greater numbers of squirrel gliders, the conservation value of some edge habitats that provide additional resources and dispersal opportunities should not be underestimated for forest-dependent mammals; however, each edge type must be assessed individually.

Surveys that record the presence or absence of fauna are used widely in wildlife management and research. A false absence occurs when an observer fails to record a resident species. There is a growing appreciation of the importance of false absences in wildlife surveys and its influence on impact assessment, monitoring, habitat analyses, and population modeling. Very few studies explicitly quantify the rate of these errors. Quantifying the rate of false absences provides a basis for estimating the survey effort necessary to assert that a species is absent with a pre-specified degree of confidence and allows uncertainty arising from false absences to be incorporated in inference. We estimated the rate of false absences for 2 species of forest owl and 4 species of arboreal marsupial based on 8 repeat visits to 50 survey locations in south-eastern Australia. We obtained estimates using a generalized zero-inflated binomial model. We presented detectability curves for each species to convey the number of visits required to achieve a specified level of confidence that resident species will be detected. The observation error rates we calculated were substantial but varied between species. For the least detectable species, the powerful owl (Ninox strenua), our standard surveys returned false absences on 87% of visits. However, our surveys of the more detectable sugar glider (Petaurus breviceps) returned a 45% false absence rate. We predict that approximately 18 visits would be required to be 90% sure of detecting resident owls and approximately 5 visits would provide 90% confidence of detecting resident sugar gliders. We fitted hierarchical logistic regression models to the data to describe the variation in detection rates explained by environmental variables. We found that temperature, rainfall, and habitat quality influenced the detectability of most species. Consideration of observation error rates could result in important changes to resource management and conservation planning.

Summary Major roads and highways disrupt ecological flows and create barriers or filters to the movement of many species of wildlife, including gliding mammals. Mitigating these impacts presents major challenges for road authorities. One approach has been the retention of forest vegetation in median strips to serve as ‘stepping stones’ for gliding mammals to cross road gaps otherwise beyond their glide capacity. A recently upgraded section of the Pacific Highway through tall open forest near Bonville in north-east New South Wales retained forest within two 10- to 45-m-wide median strips separating each carriageway and a service road. We investigated whether Sugar Gliders (Petaurus breviceps) used these median strips to cross an 85 to 135 m-wide road corridor. Three radio-collared Sugar Gliders (one male and two females) moved between both highway medians and forest on either side of the road corridor during 32 days of radio-tracking. Although the sample size is small, these results suggest that highway median strips, featuring mature vegetation with a major den tree, can provide ‘stepping stones’ for gliding mammals to cross a highway that would otherwise function as a movement barrier or filter. Longer-term research with greater numbers of animals at this and other sites is required to determine whether such strips would be commonly used when den trees are absent and whether gliding via median strips may also increase road mortality of the species.

Linear strips of natural or semi-natural vegetation are a characteristic feature of rural landscapes throughout the world. Their value for the conservation of fauna in heavily modified landscapes depends on the response of species to the linear shape of the habitat, and the pressures this imposes on population processes and spatial organization. In south-eastern Australia, woodland habitats occupied by the squirrel glider Petaurus norfolcensis, a threatened species of arboreal marsupial, have been preferentially cleared for agriculture leaving only remnants within cleared farmland. In this study, the home range of P. norfolcensis was investigated by radio-tracking 40 gliders within a highly modified landscape where the majority (83%) of remaining wooded habitat occurs as a network of linear strips along roadsides and streams. Individuals were tracked for one to four seasons, resulting in the collection of 4213 independent locational ‘fixes’. All fixes of animals were from remnant woodland. Home ranges were elongated and linear, primarily determined by the shape and arrangement of woodland habitat. Seasonal home ranges were small (mean of 1.4–2.8 ha) and ranged between 320 and 840 m long. Small patches of trees in farmland adjacent to the linear habitats were also extensively used. Despite the highly modified landscape structure, home ranges of P. norfolcensis in the linear network were smaller than those estimated from other studies of this species in continuous habitat. The apparent high quality of the linear habitats is attributed to the density of large old trees, which provide foraging and breeding resources, and the productivity of the environment. Linear landscape elements may have a valuable conservation function where they provide resident habitat or enhance landscape connectivity, but their long-term viability is vulnerable to disturbance.

Summary Small artificial nest/roost boxes, originally designed for microbats, were deployed in three farm forest plantations and at one native forest site in southeast Queensland in order to assess their use by vertebrates and their contribution toward enhancing biodiversity in plantation forests through the provision of habitat. Two sites were located in a relatively ‘intact’ forest landscape (SF 351 and Strano) and two sites in a more ‘fragmented’ or ‘variegated’ landscape (Askham and Thomas). Twenty-four boxes were placed at each site over an area covering approximately 1.2–1.8 ha. Each site was checked from five (SF 351) to nine (Askham) times between April 1996 and November 2000. The artificial nest/roost boxes were attractive to a range of small fauna that included Feathertail Gliders (Acrobates pygmaeus), Sugar Gliders (Petaurus breviceps), Squirrel Gliders (Petaurus norfolcensis) and the Yellow-footed Marsupial Mouse (Antechinus flavipes), all of which constructed nests inside boxes. Gould’s Long-eared Bats (Nyctophilus gouldi) used boxes primarily as roosts and maternity sites. In general, fewer animals were recorded in boxes at the two sites located within a relatively ‘intact’ landscape, while the highest numbers of animals were recorded in boxes in two farm forest plantations within ‘variegated’ landscapes. The availability of alternative natural hollows and landscape factors appear to be important determinants of the extent to which boxes are occupied. The present study indicates that the biodiversity of farm forests can be enhanced through simple habitat manipulation utilizing artificial roosting or nesting boxes. Key words Antechinus, biodiversity, farm forestry, glider, marsupial, microbat, nest box, roost.

Young, relatively undeveloped sugar gliders Petaurus breviceps have been observed to be left alone in the nest while the mother forages and may be subject to considerable thermal or energetic stress. As no information is available on the development of thermoregulation in this species, which begins reproduction in winter, we measured resting metabolic rate (RMR), body temperature (T b) and thermal conductance over a range of ambient temperatures (T a) in 10 sugar gliders from c. 55 days of age until they had grown to adult size. Sugar gliders were unable to maintain a stable T b over a T a range of 30‐158C until the age of 95‐100 days, although they raised RMR somewhat as T a decreased. Further growth resulted in a steady decrease in mass-specific RMR, an increase in T b and a substantial decrease in thermal conductance. Our study shows that young gliders below the age of 100 days rely largely on heat produced by adults to maintain a high T b, but are well able to cope with regular falls in T b of > 108C and a concomitant decrease of RMR. This thermal tolerance and reduction in energy expenditure should allow the mother to forage and replenish her own body fuels while her offspring are left alone in the nest.

The gliding angle of the Mahogany Glider Petaurus gracilis and the Sugar Glider Petaurus breviceps was determined from field studies by measuring the height of launch and landing of glides and the distance travelled. This showed no significant difference between these two species in glide ratio, which averaged 1.91 and 1.82 m distance per 1 m loss in altitude, respectively, nor in glide angle which averaged 28.26° and 29.69° for the Mahogany Glider and Sugar Glider, respectively. Significant differences were found between them for height of launch (19.75 and 11.96 m, respectively), height of landing (4.48 and 1.95 m, respectively), diameter at breast height of landing tree (44.12 and 23.22 cm, respectively), and glide distance (29.71 and 20.42 m, respectively). An examination of the ratio of interorbital width to maximum skull width of gliding and nongliding possums was measured from museum skulls to examine whether gliders have eyes wider apart, to allow triangulation of distance in preparation for gliding. Gliding possums showed a trend toward having a larger interorbital width than nongliding possums, although there appear to be several factors acting on the interorbital width. Museum study skins of all gliding marsupials were measured to determine the relationship between patagium surface area and body mass which showed a clear relationship (r2 = 0.9688). A comparison of gliding behaviour, patagium, development of limbs, tail morphology and mass was also made between gliding marsupials and other gliding mammals.

We describe a landscape-scale study of fragmentation effects on arboreal marsupials at Tumut, southeastern Australia. Embedded within a 55000-ha plantation of exotic Monterey pine (Pinus radiata) are 192 patches of remnant Eucalyptus forest, with large contiguous areas of eucalypt forest beyond the plantation boundary. We compared presence and estimated abundance of arboreal marsupials in three broad groups of sites: remnants of native Eucalyptus forest in the P. radiata plantation; P. radiata stands in the plantation; and large areas of contiguous Eucalyptus forest surrounding the plantation. The study animals were Trichosurus vulpecula, T. caninus, Petaurus breviceps, P. norfolcensis, P. australis, Acrobates pygmaeus, Pseudocheirus peregrinus, and Petauroides volans. We used randomized, replicated statistical procedures to sample 86 eucalypt remnants varying in size, shape, and other features. We matched 40 sites in large contiguous Eucalyptus forest to those remnants, based on environment, climate, ter...

The sugar glider Petaurus breviceps is generally considered to be a polygynous, group-nesting species. However, recent captive studies have indicated that dominance hierarchies and shared codominance amongst males formed when males were housed in multiple-male, multiple-female cages with male-biased sex ratios. This study uses data from sugar glider groups in natural populations to assess the probability of male dominance hierarchies and the opportunity for codominant father–son coalitions. Nesting groups of sugar gliders were found to have female-biased sex ratios ranging from 1:1.5 to 1:2.7 males:females. The dispersing sex was male – there were four records of recruitment into the natal group, all of which were female. Only one example was found of a long-term adult male association between a father and putative son, which did not occur in the natal group of the son. The evidence suggests that though father–son associations may occur, the opportunities for male dominance hierarchies or male coalitions are rare in sugar glider nesting groups in the natural environment.

Patterns of co-occurrence were examined among the suite of species of arboreal marsupials that inhabit the montane ash forests of the Central Highlands of Victoria, southeastern Australia. The data used in our analyses were counts of different species of arboreal marsupials derived from stagwatching surveys of 152 sites throughout the Central Highlands region. Our work investigated both the number of species that tend to occur together, as well as identity of the taxa in such associations. A total of eight different species of arboreal marsupials were recorded from field surveys of montane ash forests: Leadbeater's Possum (Gymnobelideus leadbeateri), Sugar Glider (Petaurus breviceps), Yellow-bellied Glider (Petaurus australis), Greater Glider (Petauroides volans), Mountain Brushtail Possum (Trichosurus caninus), Feathertail Glider (Acrobates pygmaeus), Common Ringtail Possum (Pseudocheirusperegrinus), and Eastern Pygmy Possum (Cercartetus nanus). Large assemblages of taxa were rare and no sites supported the full array of species of arboreal marsupials– the maximum number of species recorded on a given 3 ha site was five. The results of our analyses indicated that if any one species of arboreal marsupials was present at a site, then on average 1. 5 other taxa will co-inhabit that site. The exception was the Common Ringtail Possum. When this species was detected, few other arboreal marsupial taxa tended to be recorded with it. Principal Co-ordinates Analysis showed that although combinations of animals comprised of either Mountain Brushtail Possum, Leadbeater's Possum, or Greater Glider were often recorded, there were no strong patterns in the identities of co-occurring taxa. This finding, together with the result that most taxa in these forests typically co-occurred with one or two other species, indicates that none of the arboreal marsupials inhabiting the montane ash forests of the Central Highlands of Victoria would be a good surrogate for (or ‘indicator’ of), the presence of the suite of other species in the assemblage.

Co-operation between two or more individuals has been shown to yield benefits in some vertebrate species (Bygott, Bertram & Hanby, 1979; Packer & Pusey, 1982; Grinnell, Packer & Pusey, 1995), however, until now such behaviour has not been described for marsupials. In this two-and-a-half-year study co-operative behaviour among male sugar gliders (Petaurus breviceps) was revealed. A dominant relationship to females was not observed. Male sugar gliders not only showed extensive co-operative behaviour in suppressing subordinate males, but in sharing food and nesting boxes as well as taking care of the offspring. DNA fingerprinting has been used to describe the genetic variability in relatedness of the coalition partners. Co-operative behaviour in male sugar gliders was exclusively observed among closely related individuals, therefore supporting the kin-selection theory in this small marsupial. We describe the genetic variability in relatedness, the behaviour and some physiological parameters of male sugar gliders in four captive groups to test the hypothesis that the sugar glider is an example of co-operative behaviour involving kin selection in marsupials

The effect of gonadotrophin-releasing hormone GnRH on plasma testosterone was examined in male sugar gliders Petaurus breviceps that were judged to occupy either the highest or lowest position in stable colonies consisting of up to four males and two females. Experiment were carried out at a time when breeding occurred in two of the three colonies, as evidenced by the presence of pouch young.

Habitat destruction is causing population decline of many hollow dependent species such as gliding marsupials of the Family Petauridae. Three petaurid species are now listed in some Australian states as either threatened, rare or vulnerable, precipitating a need for information on their basic biology and population structure. We isolated and characterized three polymorphic microsatellite loci from the yellow-bellied glider (Petaurus australis) and six polymorphic microsatellite loci from the sugar glider (P. breviceps). Per-locus heterozygosities range from 42%–92%, and cross-species amplification studies show that between five and seven loci are polymorphic in the two target species as well as a related species P. norfolcensis.

The extent to which the different molar morphologies of two similar-sized mammals, Petaurus breviceps (sugar glider) and Dasyuroides byrnei (kowari), could affect the digestion of larval insect nitrogen was investigated. Nitrogen digestibility of Tenebrio larvae treated with a proteolytic enzyme (trypsin) increased with decreasing larval piece size. However, it was found that the molars of P. breviceps, with their minimal shearing capacity compared with D. byrnei, can only compress rather than finely comminute Tenebrio larvae. As a result, P. breviceps have less efficient nitrogen digestibility than D. byrnei whose shearing molars can finely comminute larvae. Petaurus breviceps molars are inefficient at breaking down insects possibly because of functional constraints, where the molars must perform several different tasks with competing morphological demands, or because of phylogenetic constraints.

Observations were made of a wild population of sugar gliders (Petaurus breviceps) by live-trapping and on four captive colonies to establish the relationship between blood concentration of testosterone, body weight, social dominance and the timing of births. In both the wild and in captivity one male exhibits a testosterone concentration far higher than his fellows, during the breeding season. This male is also the heaviest. In captivity this male is observed to be socially the most dominant and undertakes almost all of the scent-marking. At least three-quarters of each breeding season's births occur during the first month of the three- to four-month season (July-September/October), a passage of time during which the body weight of the most dominant male falls more than that of the subordinates. It is suggested that this species is highly polygynous, with the ecological and evolutionary benefits of high social status being immense.

A study spanning two breeding seasons was carried out to examine changes in the size of the dorsal paracloacal glands and testes in the marsupial sugar glider Petaurus breviceps Waterhouse 1839. These changes were related to seasonal increases in the plasma testosterone concentration and to morphological changes in the frontal and gular cutaneous scent glands of males. Both dorsal paracloacal glands and testes underwent a seasonal cycle of development which reached its maximum during the June-September breeding season. These changes coincided with an increase in the plasma testosterone concentration and with the increase in activity of certain cell types within the frontal and gular glands. Castration caused a significant decrease in the size of the dorsal paracloacal glands, while androgen replacement was effective in restoring the glands to their pre-castration size thus demonstrating the influence of androgens upon the activity of these glands. The synchronization which exists between plasma testosterone concentration, cutaneous scent gland morphology and the size of the dorsal paracloacal glands of males, suggests that the dorsal paracloacal glands, or more likely their secretions, are important in social organization in this species.

Early developmental and demographic events in many marsupials occur in the mother's pouch out of animal managers' sight. Because pouch examination is perceived as being stressful both to animal and handler, the pouch has proven to be a formidable physical and psychological barrier to the study of early life history events in marsupials in zoos. Demographic and developmental data such as litter size at birth, secondary sex ratios, infant mortality rates, and early rates of growth and development, normally considered essential information for the development of breeding programs, are therefore essentially unavailable for most zoo populations of marsupials. Here we describe a technique for the safe and non-stressful examination of the pouches of small (< 2 kg) marsupials that enables the capture of such data. The technique, involving the use of transparent plastic tubes of slightly different diameters for restraining the animals and an otoscope for examining the pouch and its contents, has been very successfully applied to life history studies of four species at the National Zoological Park: Pseudocheirus peregrinus, Petaurus breviceps, Philander opossum, and Chironectes minimus.

Summary. 1 We present a survey of the literature on the occurrence of bilateral anterior venae cavae in mammals. In some they are to be regarded as normal, in others as exceptional. 2 We ourselves have found bilateral anterior vanae cavae in two red kangaroos, two Bennett's wallabies, one African elephant, and one Indian fruit-bat; in all these animals they are to be regarded as normal. We have also found them in a lion and a brown capuchin monkey; in these animals they are to be regarded as exceptional. 3 In agreement with the observation made by Forbes (1881), we report the occurrence of a single A.V.C. in a specimen of the short-headed fiying-opossum (Petaurus breviceps Waterh.), an exception to Owen's generalization that all marsupials have bilateral anterior venae cavae.