Live-trapping of the northern hairy-nosed wombat (Lasiorhinus krefftii): population-size estimates and effects on individuals

The northern hairy-nosed wombat, one of the most endangered large mammals known, occurs only in Epping Forest National Park, central Queensland. The results of a 3-stage trapping programme, carried out between 1985 and 1993, were used to estimate population size by means of three separate modelling approaches: minimum number alive (MNA), mark-recapture, and trapping effort. Trapping procedure varied among sessions, and each estimator was applied to sessions only where its use was appropriate. The population-size estimate for 1985-86 was 67 (trap effort) with MNA of 58; for 1988-89 it was 62 (Jolly-Seber mark-recapture estimate), with MNA of 48 and upper 95% confidence limit of 77; and for 1993 it was 65 (Chao mark-recapture and trap effort), with MNA of 43 and upper 95% confidence limit of 186 (Chao mark-recapture). No population trends were observed, although variability in estimates and wide confidence intervals meant that power to do so was limited. Trapping affected the health and behaviour of wombats. Animals that were trapped twice within 10 nights lost an average of 0.62 kg (P = 0.006) between captures. Wombats that were trapped twice within the first four nights of traps being set on a burrow showed less weight loss than those trapped for the second time after 5-7 nights (0.23 kg v. 1.54 kg). The effects of trapping appeared to remain with animals for some time, since animals trapped twice more than 30 nights apart and within six months weighed an average of 0.5 kg less (P = 0.013) on second capture. When areas were trapped twice in succession with a 3-week gap, population-size estimates were lower for the second period of trapping. Thus, some wombats may have temporarily left areas disturbed by trapping. The deleterious impact of trapping may be reduced by restricting trapping to periods of four nights. Trapping effectiveness may be increased by minimising disturbance immediately before trapping and by moving traps between periods of trapping.

An experimental test of affect, subjective craving, and alcohol outcome expectancies as motivators of young adult drinking

Research on motivations for alcohol use suggests that both positive and negative affect, craving, and outcome expectancies are good predictors of alcohol consumption. The present study tested the utility of these variables in predicting laboratory measures of alcohol consumption among young social drinkers. Two conditioning models of alcohol procurement guided analyses: the conditioned withdrawal model (represented by negative affect and craving) and the appetitive-motivational model (represented by positive outcome expectancies and subjective evaluations). Results showed that negative affect and craving did not significantly influence either subjects' latencies to begin drinking or speed of consuming one placebo beverage. Positive outcome expectancies and evaluations, however, had a marked impact on speed of drinking. Thus, the appetitive-motivational model appears to better characterize the drinking patterns of young social drinkers than does the conditioned withdrawal model.

Distribution of Feeding Activity of the Tasmanian Bettong (Bettongia Gaimardi) in Relation to Vegetation Patterns

The Tasmanian bettong (Bettongia gaimardi) feeds by digging for the fruit-bodies of hypogeous ectomycorrhizal fungi in dry sclerophyll forest. This study examined variations in the density of food-diggings of B. gaimardi in relation to vegetation patterns in a 150-ha study area. Density of B. gaimardi diggings was highest in Eucalyptus tenuiramus [E. tenuiramis] forest with a high density of mature stems and little ground vegetation; this type of vegetation was found on soils of low fertility. Density of diggings also increased towards the dry end of a moisture gradient characterized by a transition from E. amygdalina to E. obliqua, and increased with the density of Acacia dealbata stems. High densities of A. dealbata probably indicate recent burning. Analysis of the fine-scale distribution of diggings showed that diggings were clustered around Eucalyptus and Acacia stems, but showed no pattern in relation to density of ground vegetation.

Synthesis and evaluation of a series of aryl[e]fused pyrazolo[4,3-c]pyridines with potential anxiolytic activity

A series of pyrazolo[4,3-c]pyridines has been synthesized and evaluated as potential anxiolytic agents. Selected compounds from this series show a pharmacological profile of action different from that of diazepam. A number of the compounds possess higher affinity for central benzodiazepine receptors than diazepam, yet show less anticonvulsant activity and are less sedative. The structure-activity relationships of these potential anxiolytic agents are discussed.

If you had my brain, where would I be? Children's understanding of the brain and identity

When do children distinguish a person's subjective identity from their outward bodily characteristics? As adults this distinction is evident in our commonsense recognition that a hypothetical brain transplant would entail a transplant of the mind or self. 4 studies were conducted to examine children's judgments about hypothetical body part transplants, including transplants of the brain, heart, mouth, and face. The results showed that during the elementary school years children are acquiring a firm understanding of the brain as the primary locus of psychological attributes and identity. The early school years, between the ages of 5 and 7 years, appeared to be a transitional phase, with performance being variable and subject to task conditions. While children this age readily imagined the consequences of transplants between themselves and another character of categorically different status (i.e., a pig or baby), they had great difficulty with proposed transplants between themselves and another child of the same status. Knowledge about categorical differences appeared to provide a needed framework for children's budding thinking about psychological differences.

Macropod Studies at Wallaby Creek .8. Individual Recognition of Kangaroos and Wallabies

Recognition of individual large mammals by natural features is an ancient practice, the usefulness of which has recently become appreciated in field studies. We show that such recognition is possible and repeatable, under particular circumstances, with macropodid marsupials in the field in Australia. In trials, there was a 98% agreement between observers in identification of individuals of both eastern grey kangaroos Macropus giganteus and red-necked wallabies M. rufogriseus. Characters used to identify individuals were first definitive ('oddity') characters, and then specific sets of character-states. However, in time observers came to recognise individuals 'on sight', by unconscious summation of character-states. Recognition skills could be readily learned by observers, allowing almost complete populations of these species to be known and the component members studied individually. The technique should be applicable in studies of other macropodid populations.

Dispersal and the sex ratio at birth in primates

The females of many species of primates settle for life within the home ranges of their mothers, whereas males disperse as immatures. According to the theory of sex allocation, the costs incurred by mothers through local competition for resources with their philopatric daughters should favour the evolution of male-biased sex ratios at birth. I report here two tests of this hypothesis based on data from 15 genera of primates. First, I show that the intensity of competition for resources within kin groups is strongly and positively correlated with sex ratios at birth. Second, I show that sex ratios at birth are higher in genera with female-biased philopatry than in genera in which philopatry is not female-biased. These analyses suggest that local resource competition among kin powerfully influences the evolution of sex ratios in primates.

Macropod Studies at Wallaby Creek .1. The Area and Animals

This paper introduces a series of papers on the ecology, social organisation and behaviour of populations of sympatric macropods (Macropodoidea : Marsupialia) in north-eastern New South Wales. The study site, in the valley of Wallaby Creek, covers partly tree-cleared cattle-grazed pastures and also wet and dry forest communities; 10 species of macropods live there. The valley has a moderately high rainfall (1023 mm per annum), falling predominately in summer, and an equable climate of cool winters and warm summers. Soils derived from sedimentary and basaltic rocks and alluvium support naturally diverse plant associations further diversified by clearing and establishment of pasture and weed species. Macropods favouring open country occupy the pastures, which can also be used by cover-dependent species where pasture abuts forest or remnant patches of cover. Composition of the macropod community has changed since development of the pasture zone. Dingoes, major predators of some of the macropods, are abundant, and all exotic mammals other than cattle are rare. Populations of two of the macropod species are habituated to approach by observers, and close observation, on foot, of undisturbed animals has become our common study technique. A 1-ha grid has been established over 3.7 km2 of the study site to facilitate exact location of animals and observations. The suitability of the macropod populations for this kind of study results from the attitudes of the landholders.

Variations in Group Size and Composition in Red and Western Grey Kangaroos, Macropus rufus (Desmarest ) and M. fulignosus (Desmarest)

Data on group size and composition in red and western grey kangaroos are analysed with respect to population density and season. In red kangaroos, typical group sizes were correlated with density at all times of the year. Analyses of density-group size relationships in each sex showed female typical group size to be correlated with female density but male densities and group sizes to be uncorrelated. Small adult males were the least likely to be with near-oestrous females, and apparently tend to disperse into suboptimal habitats. In the seasonally breeding western grey kangaroos, densities and typical group sizes were correlated during spring and summer, but not during autumn and winter, when groups tended to be larger. This seasonal shift is mainly due to changes in the grouping behaviour of males. These patterns are interpreted as being due to dominance relationships and seasonal reproductive strategies of males.

Behaviour of the Bilby, Macrotis lagotis (Reid), (Marsupialia : Thylacomyidae) in Captivity

The behaviour was observed, in captivity, of the bilby Macrotis lagotis, a fossorial bandicoot of central Australia. Most of the observations were made at night, but some were of below-ground behaviour during the daylight hours. Bilbies proved to be relatively passive in comparison with other bandicoots, and a rigid dominance hierarchy amongst males was maintained without destructive fighting. Dominant males chased subordinate males out of and away from burrows and the alpha male maintained priority of access to all the well used burrows in the enclosure. Males scent-marked around burrows; the dominant male usually marked over scents left by other bilbies. Males shared burrows freely with females, and copulation appears to take place down burrows. Information is also given on female-female and mother-young behaviour, and some suggestions are made concerning the social structure of wild bilbies. Activity cycles, feeding behaviour, etc. are described.

Children's developing conceptions of the mind and brain

Previous investigators have examined children's knowledge about particular cognitive performances such as metamemory, or particular mental acts, such as dreams. The present research adds a new dimension by considering children's concepts of the mind as a whole. The development of concepts of both the mind and brain is examined in subjects from preschool age through adulthood. Evidence is presented to show that by ages 4 and 5 years children commonly regard the brain as an internal mindlike entity associated with a class of distinctly mental acts. This runs counter to previous characterizations of young children as failing to distinguish mental from overt behavioral acts. Young children begin with undifferentiated conceptions of the mind and brain. Both entities are regarded as necessary for mental, but not sensory-motor actions. In subsequent developments, the concepts of the mind and brain are differentiated along 2 lines. Ontologically, the mind is distinguished by its immateriality; functionally, the brain is distinguished by its involvement in bodily actions. The development of knowledge about the brain is discussed with respect to acquiring "popular" and "technical" definitions. The results are regarded as contributing toward understanding how children come to organize information about the mental world as a whole.

Habitat Selection by Sex, Age and Reproductive Class in the Red Kangaroo, Macropus rufus, in Western New South Wales

The kangaroo populations of Kinchega National Park respond differently to shifts in pasture productivity, red kangaroos Macropus rufus being mobile and unevenly distributed with respect to soil and vegetation types, by comparison with the more evenly dispersed western grey kangaroos M. fuliginosus and the sedentary and localized euros M, robustus erubescens. Red kangaroo population classes tend to be differentially distributed, so that large males and heavily lactating females predominate on the seasonally preferred pastures, while other classes tend to predominate elsewhere. This finding has several implications for the management of red kangaroos and for our understanding of their resource ecology and mating systems.