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Many petrels show no obvious sex-linked dimorphism in plumage or size and consequently many researchers fail to sex the living individuals they study. Several methods of sex discrimination that do not rely on plumage- or obvious size-dimorphism can be used to sex live petrels. The effectiveness of three such techniques was evaluated: body condition at the time of laying, cloacal inspection, and discriminant function analysis (DFA) of external morphometrics. Gould's Petrel (Pterodroma leucoptera leucoptera) was used as the subject species. Sexing of breeding adults on the basis of body condition at laying proved to be highly accurate (100% of birds sexed correctly) but required detailed knowledge of the breeding biology. Following training, cloacal inspection proved to be an accurate (96%) method of determining the sex of breeding adults, but not of chicks. Unlike molecular sexing, the latter two methods of sex discrimination provide immediate knowledge of the sex of individuals in the field. DFA of external morphometrics predicted the sex of adults with an accuracy of 73% and the sex of near-fledged chicks with an accuracy of 66%. However, the probability of correct assignment of sex was low in most cases and, therefore, this is the least useful of the three techniques assessed here.

Malleefowl eggs were collected from the wild and incubated artificially. Week-old chicks were released into four I-ha enclosures of natural mallee vegetation. Water was placed into one enclosure, rabbits into another, seed into a third and a fourth was left unaltered. Of 20 chicks released into the non-seeded enclosures, all survived only 1-22 days (median = 4 days). Starvation was the underpinning cause of death, individuals losing body weight at a rate of up to 7% day-1. Chicks without sufficient food were more susceptible to chilling, particularly after rain, and more vulnerable to raptors than those fed ad libitum. Of nine chicks released into the enclosure with supplementary food, only one died (as a result of chilling six days after release); all the rest survived beyond 30 days (the duration of the experiment). Subsequent transfer of surviving chicks from the enclosure with supplementary food to others containing only natural mallee vegetation resulted in their body weight decreasing up to 6.4% day-1, sufficient to cause the death of one chick after just three days.

Free-ranging red and western grey kangaroos were fitted with radio transmitters which, when the kangaroo grazed, emitted a pulse rate different to that emitted during other activities. Red kangaroos grazed for between 7.1 and 10.5 h day-1; western grey kangaroos grazed for between 5.9 and 9.8 h day-1 . Red kangaroos grazed for the same amount of time each season despite fourfold changes in pasture biomass. The grazing time of western grey kangaroos was similar in autumn, winter and spring, but decreased by 22% in summer when pasture was most abundant. Males of both species grazed for about an hour longer than females each day. Most grazing (78% for red kangaroos; 86% for western grey kangaroos) took place between sunset and sunrise. The distribution of grazing activity with respect to time of day was bimodal; kangaroos grazed for extensive periods during the 6 h immediately after sunset and again during the few hours before and after sunrise. The time of grazing changed seasonally and these changes were associated with differences in daylength.

Captive-reared juvenile Malleefowl Leipoa ocellata (3-5 months old) experimentally released into Yathong Nature Reserve did not survive. From the first day after release Malleefowl were found dead, and mortality continued at a rapid rate until none remained alive: 50-58% were dead within 7 days; 83-96% were dead within 36 days; and none survived longer than 104 days. Predation by the introduced Red Fox Vulpes vulpes was the principal cause of mortality, accounting for at least 50% and perhaps as many as 92% of young Malleefowl. Twelve older captive-reared sub-adults (14-28 months of age) experimentally released into Yathong Nature Reserve fared somewhat better; three survived longer than 428 days. Again, predation by foxes was the chief cause of mortality. Mortality was particularly high during the first week following liberation, but the two age classes differed in their long-term survival. One third of sub-adults survived to breeding age (2.5 years), while no juvenile survived its first year. This implies a decrease in the vulnerability of Malleefowl to foxes between the first and subsequent years of life. Predation by foxes remained the major cause of mortality among sub-adults. Fox predation may well threaten the continued survival of Malleefowl in New South Wales because they killed sub-adult Malleefowl of a weight comparable to that of many adults, which suggests that the duration of vulnerability to foxes is protracted. Furthermore, this threat is not confined to the fragmented remnants of mallee vegetation within the wheat-belt but extends to Malleefowl populations in the remaining large expanses of mallee, remote from agriculture.

The remains of adult Gould's Petrels Pterodroma leucoptera leucoptera were recovered from the nesting site on Cabbage Tree Island, New South Wales. Entanglement in the sticky fruits of the Bird-lime Tree Pisonia urnbellifera was identified as a major cause of mortality. Removal of P. urnbellifera eliminated one cause of death but mortality of adult petrels continued at an unsustainable rate as the result of predation by the Pied Currawong Strepera graculina. Hunting and feeding behaviour of the Pied Currawongs were observed, including holding fast a petrel carcass while ripping flesh from the skeleton. Mortality of Gould's Petrels subsided immediately following the destruction of Pied Currawong nests and nestlings. Subsequent recurrences of predation were correlated with additional nesting attempts by Pied Currawongs but declined substantially following the instigation of a control program for Pied Currawongs on Cabbage Tree Island. Pied Currawongs take the eggs and nestlings of many species of birds, but losses of nesting adults or the decline of a seabird have not been attributed previously to currawong predation.

Home ranges of sympatric red kangaroos, Macropus rufus, and western grey kangaroos, M. fuliginosus, were determined by radiotracking 48 individuals over 20 months. More than 90% of individuals of each species remained within home ranges of less than 10 km2 (mean SE, 7.74 0.90, reds; 6.92 0.77, western greys). At no time did any individual disperse far, the longest movement being 13 km. Based on diurnal locations (resting sites) only, home ranges of red kangaroos were larger than those of western greys (P

Habitat utilisation by sympatric red kangaroos, Macropus rufus, and western grey kangaroos, M. fuliginosus, was monitored by aerial survey. Red kangaroos used floodplain and sandplain with equal intensity. Western grey kangaroos favoured floodplain and utilised woodland on both landforms relatively more than did red kangaroos. Movements of kangaroos between sandplain and floodplain paralleled changes in pasture condition. Red kangaroos responded to pasture growth, moving to sandplain immediately after rain. Western greys followed up to 3 months later, the increase in use of sandplain being weakly correlated (r = 0.70) to an increase in pasture biomass. There was no evidence of any temporal change in use of either woodland or open plain by either species.

Radiotelemetry was used to track 18 Nyctophilus gouldi to roosts in 38 trees within a logged forest. The species and sizes of trees selected by the bats were compared to trees measured in six randomly located plots in each of four major habitats. Only the unlogged gullies provided the species of trees required by the bats for roosting. Of these, the bats showed strongest preference for those trees with a diameter greater than 80 cm. As the first logging cycle removed many suitable roosts, we conclude that the second logging cycle, due before the turn of tbe century, will have a major deleterious impact on the local survival of N. gouldi unless gullies remain unlogged. This would require the redefinition of gullies in the forest management plan to include all drainage lines.

Between July 1979 and November 1980 a total of 261 red kangaroos, Macropus rufus, (216F; 45 M) and 170 western grey kangaroos, M. fuliginosus, (136F;34M) were caught and tagged with individually recognisable collars. Between July 1979 and January 1986, 1751 sightings of tagged individuals were recorded. Information gained from these sightings was used to assess how far each kangaroo ranged. More than 90% of individuals of either species did not range far (<9 km for reds; <6 km for western greys) even when local pastures were severely depleted during drought. A few individuals dispersed much further-up to 323 km. On average, red kangaroos ranged further than western greys. Kangaroos on Kinchega National Park ranged no less or no further than those on an adjacent pastoral leasehold. At least 17 tagged individuals crossed the macropod-deterrent fence surrounding Kinchega; several crossed repeatedly. Dispersal of kangaroos from Kinchega was slight, supporting the hypothesis of Bayliss (1985) that dispersal has no significant impact on population dynamics.