bluuebunny/crossref_metadata_2025 huggingface dataset:
Initial effects of rabbit haemorrhagic disease on free-living rabbit (Oryctolagus cuniculus) populations in central-western New South Wales
Authors: Saunders Glen , Choquenot David , McIlroy John , Packwood Rossanne
Published: January 2006

Quarterly spotlight counts of rabbits were conducted at three sites in
central-western New South Wales. These counts commenced two years before the
arrival of rabbit haemorrhagic disease (RHD) in the winter of 1996. The
existing data on quarterly rates of change in rabbit abundance for the three
populations provided a unique opportunity to study the effects of RHD on
rabbit demography. Prior to the arrival of RHD, all three populations
underwent phases of sequential increase and decrease in each year. On the
basis of these patterns, RHD had a variable influence on the demography of the
three rabbit populations. In 1996–97, the density of two populations
declined over an expected period of increase, while at the third site the
density increased as expected from pre-RHD patterns. Twelve months after their
failure to generate expected positive rates of increase the two affected
populations had returned to the normal sequence of increases and decreases in
density although still at comparatively low numbers.
Influence of shade covers on pitfall trap temperatures and capture success of reptiles and small mammals in arid Australia
Authors: Hobbs Trevor J. , James Craig D.
Published: January 2006

Shade covers for pitfall traps can be used to reduce the amount of solar
radiation penetrating to the bottom of pitfall buckets, thereby reducing the
number of captured animals dying from heat-stress. We tested the effectiveness
of a variety of shade covers for reducing temperatures in pitfalls and trap
mortality of small vertebrates, and examined the effect of one cover design on
trap success in arid landscapes. Shade covers made of insulation foil were
found to reduce core pitfall temperatures by 20–22˚C compared with
uncovered buckets, which reached temperatures greater than 66ºC. Other
cover types tested (plastic lid or cardboard) were found to be less effective:
core bucket temperatures still reached 48–53ºC. While foil covers
do reduce temperatures and therefore the probability of heat-stress-related
mortality, above-ground foil covers also influence trap success. Traps with
above-ground foil covers caught 39–43% fewer small vertebrates
and 7–42% fewer species than uncovered traps. Above-ground foil
covers had the greatest influence on the sampled abundance of scincid lizards
(reduced by 50–52%), reduced the sampled abundance of most other
lizard families and mammals, but increased capture success for snakes. If
shade covers are required to minimise heat stress and mortality in pitfall
buckets we recommend foil covers placed inside the bottom pitfall buckets as
they significantly reduce pitfall temperatures and are likely to have minimal
influence on trap success. However, regular checking of traps is still one of
the most reliable ways to reduce heat-stress- related and other deaths in
pitfall traps.
When, where and why do people encounter Australian brownsnakes (Pseudonaja textilis : Elapidae)?
Authors: Whitaker P. B. , Shine R.
Published: January 2006

Encounters between humans and dangerously venomous snakes put both
participants at serious risk, so the determinants of such encounters warrant
attention. Pseudonaja textilis is a large fast-moving
elapid snake responsible for most snakebite fatalities in Australia. As part
of a broad ecological study of this species in agricultural land near Leeton,
New South Wales, we set out to identify factors influencing the probability
that a human walking in farmland would come into close proximity to a
brownsnake. Over a three-year period, we walked regular transects to quantify
the number and rate of snake encounters, and the proportion of snakes above
ground that could be seen. The rate of encounters depended upon a series of
factors, including season, time of day, habitat type, weather conditions (wind
and air temperature) and shade (light v. dark) of the observers’
clothing. Interactions between factors were also important: for example, the
effect of air temperature on encounter probability differed with season and
snake gender, and the effect of the observers’ shade of clothing
differed with cloud cover. Remarkably, even a highly-experienced observer
actually saw <25% of the telemetrically monitored snakes that were
known to be active (i.e. above ground) nearby. This result reflects the
snakes’ ability to evade people and to escape detection, even in the
flat and sparsely vegetated study area. The proportion of snakes that were
visible was influenced by the same kinds of factors as described above. Most
of the factors biasing encounter rates are readily interpretable from
information on other facets of the species’ ecology, and knowledge of
these factors may facilitate safer coexistence between snakes and people.
Population dynamics and life history of the mahogany glider, Petaurus gracilis, and the sugar glider, Petaurus breviceps, in north Queensland
Authors: Jackson Stephen M.
Published: January 2006

Mahogany gliders, Petaurus gracilis, and sugar gliders,
Petaurus breviceps, were trapped in an area of open
woodland in north Queensland between 1994 and 1996 to examine their population
ecology and life history. This study area contained two smaller areas, one
consisting of continuous habitat and the other an area of fragmented habitat
adjacent to the continuous habitat. Within the continuous area, the mahogany
glider had an average density of 0.24 ha–1 whereas
the sugar glider had an average density of 0.27
ha–1. In contrast, the density of mahogany gliders
in the fragmented habitat averaged only 0.16 ha–1
whereas the density of sugar gliders was higher, at 0.46
ha–1. Both the mahogany glider and the sugar
glider showed sexual dimorphism in their weight, head length and head width.
The average body weight of both species fluctuated throughout the year with no
consistent pattern. The mahogany glider showed a distinct breeding season,
with births being recorded between April and October, whereas the sugar glider
showed no pattern, with births being recorded during all months except
February and April. During the study, all adult females of both species were
observed to have bred, with an average litter size of 1.55 and a natality rate
of 2.09 for the mahogany glider, and an average litter size of 1.83 and a
natality rate of 2.14 for the sugar glider. The sugar glider was able to raise
two litters of young within a single year whereas a second litter was raised
by the mahogany glider only if the first litter was lost.
Habitat relationships of the mahogany glider, Petaurus gracilis, and the sugar glider, Petaurus breviceps
Authors: Jackson Stephen M.
Published: January 2006

Trapping data of the mahogany glider, Petaurus gracilis,
and the sugar glider, Petaurus breviceps, in sympatry,
in north Queensland, were analysed with vegetation variables to determine the
habitat relationships of these two species. The study area contained a
trapping grid (80 traps) within an area of continuous forest and trapping
transects within an adjacent area of fragmented forest (44 traps). The
mahogany glider was trapped more often at 43 of the 124 locations (38 in the
continuous and 5 in the fragmented forest), with the sugar glider dominant at
46 locations (18 in the continuous forest and 28 in the fragmented forest).
The remaining 27 trap locations where gliders were caught did not favour
either species. Eight trap locations within riparian rainforest had no
captures of either species. The presence of mahogany gliders was significantly
correlated with the presence of Corymbia clarksoniana,
Eucalyptus platyphylla, the absence of
Corymbia intermedia and
Acacia mangium, and a small mid and upper canopy cover.
In contrast, the presence of sugar gliders was most correlated with a large
number of stems. When the presence of the mahogany glider was compared with
that of the sugar glider with respect to various habitat variables for the
entire study area, the mahogany glider was most associated with the presence
of C. clarksoniana,
Eucalyptus pellita,
Lophostemon suaveolens,
Melaleuca dealbata and a reduced lower and upper canopy.
In contrast, the sugar glider was most associated with
C. intermedia, A. mangium, a large
number of potential food species, rainforest species and a dense mid and upper
canopy cover.
Home-range and den use of the mahogany glider, Petaurus gracilis
Authors: Jackson Stephen M.
Published: January 2006

The home-range of the mahogany glider was estimated, and its social behaviour
examined, by following radio-collared animals over a two-year period within an
area of continuous habitat and an adjacent area of fragmented habitat. The
average home range within the continuous habitat was 19.25 ha for males and
20.34 ha for females, with male and female pairs occupying a combined area of
23.15 ha. In contrast, the average home range in the fragmented habitat was
11.05 ha for males and 6.80 ha for females, with a combined home-range of male
and female pairs being 11.60 ha. The average overlap of the home ranges of
paired males and females was 85.9%, compared with approximately
11% for non-paired individuals, which suggests that mahogany gliders
are socially monogamous. For a total of 46 nights on which gliders were
considered to behave normally for the entire night, the average foraging
distance was 1506 m (range 590–3420 m) with no significant difference
between males and females in either the continuous or fragmented habitat.
There was, however, a significant difference in the distance individuals
travelled during different times of the year, with longer distances being
travelled during late dry season/wet season and shorter distances during
the early to mid dry season. Mahogany gliders also travelled further when
there was a high availability of nectar and pollen than when there was lower
availability. A total of 83 dens (tree hollows) were recorded for the mahogany
glider, with the poplar gum, Eucalyptus platyphylla,
forest red gum, Eucalyptus tereticornis, and
Clarkson's bloodwood, Corymbia clarksoniana, being
most used.
Seal survey in the Great Australian Bight region of Western Australia
Authors: Dennis T. E. , Shaughnessy P. D.
Published: January 2006

In December 1996, a survey by helicopter of the Baxter Cliffs region of the
Great Australian Bight in Western Australia did not locate any previously
unreported colonies of the Australian sea lion or New Zealand fur seal.
Although geologically contiguous with the Bunda Cliffs in South Australia
(where sea lions have a scattered distribution), the Baxter Cliffs appeared
generally more weathered and stable, with fewer collapsed sections of cliff
forming platforms and providing habitat for seals.
In total, 29 Australian sea lions were observed during the survey. Most were
at a previously surveyed site approximately 2 km west of Twilight Cove. Ten
other sites were recorded as potentially providing haul- out opportunity for
sea lions; they were mainly caves and deep overhangs with access from the sea.
No fur seals were seen.
From this survey and from other records, we estimate the Australian sea lion
population along the Baxter Cliffs in the Great Australian Bight region of
Western Australia at less than 100 animals.
Reproduction in the Proserpine rock-wallaby, Petrogale persephone Maynes (Marsupialia : Macropodidae), in captivity, with age estimation and development of pouch young
Authors: Johnson Peter M. , Delean J. Steven C.
Published: January 2006

Reproduction in the Proserpine rock-wallaby,
Petrogale persephone, was studied in captivity. Sexual
maturity, defined as age at first fertility, was attained at 20.5 months in
females whereas males were not mature until 24.8 months.
P. persephone is capable of breeding throughout the
year. The length of the oestrous cycle was 33–38 days, while the period
of gestation was 30–34 days. Birth was usually followed by an oestrus
and mating, and a subsequent lactation-controlled embryonic diapause. The mean
interval between loss of a pouch young and birth was 31.5 days. Pouch life was
203–215 days and young at foot were weaned 105–139 days after
permanent emergence from the pouch. Linear mixed-effects models were used to
describe polynomial growth equations for age determination of pouch young
using both head and pes length. The relationship between error in age
prediction and each body measurement was defined. Head measurements provided
the most accurate estimates of the age of pouch young.
Foraging behaviour and diets of red-necked stints and curlew sandpipers in south-eastern Australia
Authors: Dann Peter
Published: January 2006

Diet and feeding behaviour of red-necked stints
(Calidris ruficollis) and curlew sandpipers
(Calidris ferruginea) feeding in mixed flocks during the
non-breeding season were investigated in Western Port in Victoria,
south-eastern Australia. Surface pecking was the most common feeding action of
both species, followed by jabbing for red-necked stints and probing for curlew
sandpipers. Mean depths of substrate penetration were 3.4 mm (red-necked
stints) and 14.0 mm (curlew sandpipers). The preferred feeding zone for
red-necked stints was wet mud (86%) and for curlew sandpipers was
shallow water (40%).
Feeding rate did not vary between species but did vary between months and age
classes for curlew sandpipers. Gastropods made up 68% of the sample
volume for stints and two unidentified species in the families Hydrococcidae
and Fossaridae occurred most frequently in terms of occurrence in the guts and
total prey items. Curlew sandpipers took a wider variety of taxa (12) than did
red-necked stints (8), with polychaete worms (Nereidae) being their most
frequently recorded prey and comprising 63% of the volume of the gut
samples. When prey taxa overlapped in the diets of the two species, some size
differences of prey were apparent. Differences in bill morphology and feeding
behaviour, including microhabitat use, corresponded with these differences in
diets.
The tree species preferences of koalas (Phascolarctos cinereus) inhabiting forest and woodland communities on Quaternary deposits in the Port Stephens area, New South Wales
Authors: Phillips Stephen , Callaghan John , Thompson Valerie
Published: January 2006

An assessment of the tree species preferences of koalas inhabiting forest and
woodland communities growing on Quaternary deposits in the Port Stephens area,
New South Wales, was undertaken between November 1994 and March 1996. Using a
plot-based methodology, 3847 trees were sampled, comprising 15
Eucalyptus species and 17 species of non-eucalypt.
Evidence of tree use by koalas, specifically the presence of koala faecal
pellets, was recorded from beneath 10 Eucalyptus species
and 9 species of non-eucalypt. Tree species preferences were determined by
analyses of log- likelihood ratios derived from data based on the
presence/absence of koala faecal pellets, rather than on gross counts.
This approach confirmed significant variation in the levels of utilisation
amongst and between different tree species, and that two in particular –
swamp mahogany (E. robusta) and drooping red gum
(E. parramattensis) – were most preferred.
Increases in the levels of use of other tree species were also positively
associated with the presence of E. robusta and/or
E. parramattensis. Levels of utilisation of
E. robusta and E. parramattensis
did not alter significantly in response to changes in their respective
densities, suggesting that the relative abundance of both was important in
terms of understanding the carrying capacity of vegetation communities
utilised by koalas. The results have established the success with which an
enumerative approach to the interpretation of faecal pellet data can be
utilised to clarify the tree species preferences of koalas. Application of the
approach for habitat assessment and mapping purposes is also discussed.
1080-induced bait aversions in wild possums: influence of bait characteristics and prevalence
Authors: O'Connor C. E. , Matthews L. R.
Published: January 2006

The current experiment aimed to determine the proportion of wild-caught
possums from previously poisoned and non-poisoned populations that developed
aversions to 1080 baits. In addition, we aimed to identify the bait
characteristics mediating the ongoing aversions. In an initial test, animals
from areas previously exposed to a 1080 control-operation avoided 1080 baits
(60–80%), whereas few naive animals (0–20%) avoided
these baits. The baits comprised a green-dyed, cinnamon-lured cereal loaded
with 0.08% 1080. As a result of the exposure to the toxic baits, over
80% of the naive animals subsequently developed aversions to those
baits. Sixty-nine of these averse animals were allocated to one of 16
bait-treatment groups in a factorial design balanced for population, sex, age
and bodyweight. Each bait was characterised by four factors: (a) presence or
absence of 1080, (b) presence or absence of green dye, (c) lure type (cinnamon
or orange), and (d) bait type (No. 7 or carrot). The presence or absence of
1080 or green dye did not influence the degree of bait avoidance. Lure type
had a significant effect on consumption, with 53% of possums avoiding
an orange bait compared with 73% for cinnamon baits. Bait type also had
a significant effect on avoidance rates, with carrot baits being avoided by
42% of possums compared with 83% for No. 7 baits. Changing the
bait type would appear to hold the greatest promise for overcoming aversions
by possums to cereal bait.
Distribution and density estimates for urban foxes (Vulpes vulpes) in Melbourne: implications for rabies control
Authors: Marks Clive A. , Bloomfield Tim E.
Published: January 2006

The distribution and density of red fox populations was investigated in
metropolitan Melbourne from 1990 to 1993. Distribution data were collected
from sightings reported by members of the public, from spotlight and active
den surveys, and from trapping and road kills. Archival data suggested that
resident populations of foxes have been present within the inner metropolitan
area since the early 1940s. Contemporary fox populations were found to be
extensively distributed throughout the urban area, with few 1-km
2 grids within a 5-km radius of the Central Business
District not containing foxes. Density estimates were based on
nearest-neighbour analysis of active natal dens in four field sites.
Observations of cubs over a 4-year period at 17 dens within the field sites
revealed a mean litter size of 4.36 cubs. Mean 4-year density estimates for
each field site, immediately after the breeding season, were 0.47–2.55
dens km −2, which was estimated to represent
3–16 foxes km −2. Density estimates may be
conservative, as family groups may contain more than one non-breeding adult.
The implications of these data are discussed with respect to the potential
role of the urban fox in the epidemiology of rabies. It was concluded that fox
populations at the field sites were of sufficient density to maintain a
sylvatic epizootic of rabies.
Prediction of the distribution and abundance of small mammals in the eucalypt forests of south-eastern Australia from airborne videography
Authors: Coops N. C. , Catling P. C.
Published: January 2006

The relationship between forest structure or habitat complexity and
distribution and abundance has been demonstrated for a variety of mammalian
species in the southern forests of Australia. Recently, studies that utilise
airborne videography data have predicted forest structure across forested
landscapes. This paper unites these two fields of research. Existing models of
species abundance were applied to spatial estimates of habitat complexity to
produce predictions of the distribution and abundance of two small
ground-dwelling mammals commonly found in eucalypt forests. The spatial
estimates of habitat complexity were extrapolated across the landscape from
videography at 2-m spatial resolution on four 1-km 2 study areas. To examine
the accuracy of the abundance predictions, trapping grids for the two species
were established across a range of abundances. Linear regression showed a
strong positive relationship between the predicted distribution and abundance
from the videography and the recorded distribution and abundance for the
species.
Ecology and population biology of long-nosed bandicoots (Perameles nasuta) at North Head, Sydney Harbour National Park
Authors: Scott L. K. , Hume I. D. , Dickman C. R.
Published: January 2006

The population biology, habitat utilisation and diet of a small, isolated
population of long-nosed bandicoots (Perameles nasuta)
was studied over a 22-month period at North Head in Sydney Harbour National
Park, New South Wales. Reproductive output in this urban environment was high,
with a mean litter size of 2.3 and production of up to four litters per year.
The peak of reproductive activity was in late spring and early summer, with a
cessation of breeding in late autumn or early winter. The main causes of death
were identified as road trauma (58% – probably an overestimate
because of the ease of finding road deaths) and predation by cats and foxes
(37% – probably an underestimate because of the difficulty of
locating carcasses unless radio-collared). Bandicoots utilised all
macrohabitats (open grassed areas, heath, forest, swamp and scrub), but
extensively used open grassed areas for foraging. Males had larger home ranges
(4.4 ± 0.8 ha) than females (1.7 ± 0.2 ha). The largest home
ranges of males coincided with the peak of the breeding season
(September–November). Throughout the year
P. nasuta fed primarily on beetles, invertebrate larvae
and ants, but also on other invertebrates and on plant and fungal material.
Some vertebrate and human- derived material (birdseed, vegetable scraps,
plastic, twine) was also eaten. Although remarkably adaptable in its
reproductive and dietary strategies, this population of long-nosed bandicoots
is likely to follow other urban bandicoot populations toward extinction unless
there is active management to reduce the high rate of mortality from motor
vehicles and introduced predators.
Fox control and rock-wallaby population dynamics - assumptions and hypotheses
Authors: Hone Jim
Published: January 2006

Previous studies have demonstrated that the abundance of rock-wallabies can
increase after fox control. The assumptions made to explain the increases are
examined. Testable hypotheses are described to explain the observed increases.
Testing of the hypotheses is encouraged.
Control of introduced Rattus rattus L. on Lord Howe Island. I. The response of mouse populations to warfarin bait used to control rats
Authors: Billing Justin , Harden Bob
Published: January 2006

Warfarin bait has been used since 1986 to control introduced black rats
(Rattus rattus) in palm-seeding areas on Lord Howe
Island, New South Wales. We examined the relationship between bait use and
mouse numbers in these areas. In the first experiment, one mouse population
was manipulated by removal trapping while baiting for rats was being
undertaken. When mouse density was reduced by approximately 193
ha–1, bait consumption fell by 80.0%,
suggesting that the mice were not susceptible to warfarin and that the rat
bait may have been an important food resource for these mice. During the
second experiment, the existing rat-baiting regime was maintained in one area
but manipulated in another – bait was removed for one year then returned
during the second year. Under the existing baiting regime, mouse numbers
increased during the two-year period. The mouse population that was denied rat
bait declined to near zero after one year, then increased when bait was
reintroduced to the area, reaching densities after one year similar to those
in the area where bait had been maintained. We conclude that the mice were
resistant to warfarin, consumed most of the bait distributed to control rats,
were largely dependant on the bait as a food source, and reached high
densities in rat-control areas as a direct result of rat-baiting strategies.
The control of introduced Rattus rattus L. on Lord Howe Island. II. The status of warfarin resistance in rats and mice
Authors: Billing Justin
Published: January 2006

Black rats (Rattus rattus) and house mice
(Mus musculus) from Lord Howe Island were live-trapped,
housed in the laboratory and tested for resistance to the anticoagulant poison
warfarin. All rats fed warfarin (0.025% w/w) in their diet died
within 4–12 days whereas no rats in the untreated group died. Mice fed
warfarin at the same concentration over 21 days all survived. Black rats on
Lord Howe Island remain susceptible to warfarin, but house mice appear
resistant.
The efficacy of nestboxes versus spotlighting for detecting feathertail gliders
Authors: Ward S. J.
Published: January 2006

A series of spotlight transects were carried out over a two-year period within
a 7-ha area of the Wombat State Forest, Victoria, which contained nestboxes
used by feathertail gliders, Acrobates pygmaeus.
Spotlighting was carried out on foot through open forest, not along tracks,
and only one feathertail glider was detected in 13.8 h of spotlighting. The
nestboxes were checked on days following spotlighting surveys and 72 captures
of feathertail gliders were made over the same two- year period. Spotlighting
can provide important information on the biology of feathertail gliders when
used in long-term scientific studies by experienced spotlighters. However, it
is an unsatisfactory technique for broad surveys of feathertail gliders, and
nestboxes provide a better technique but require a longer time-frame and
additional cost.
Assuring that 1080 toxicosis in the red fox (Vulpes vulpes) is humane: fluoroacetic acid (1080) and drug combinations
Authors: Marks Clive A. , Hackman Charles , Busana Frank , Gigliotti Frank
Published: January 2006

Fluoroacetic acid (1080) is frequently used to poison the introduced red fox
(Vulpes vulpes) in Australia. The symptoms of 1080
poisoning in dogs appear extremely distressing to observers as manic running,
yelping and convulsing are readily interpreted as being indicative of pain and
distress. Assessment of pain perceived by animals poisoned by 1080 is
difficult, as severe CNS disruptions alter behaviour and EEG patterns that may
otherwise be useful in such assessments. This study compared three drug agents
combined with 1080 to address the possibility of pain and distress that may be
experienced by foxes during 1080 toxicosis. A mixed-sex group of 15 foxes was
used in the trial of each of the three drugs: an analgesic (carprofen; 10 mg
kg–1), an anxiolytic/sedative (diazepam; 10 mg
kg–1) or an analgesic/sedative (clonidine;
0.75 mg kg–1). Each group of 15 foxes was randomly
allocated between three treatments of either 0.5 mg
kg–1 of 1080, 0.5 mg
kg–1 of 1080 and a dose of the trial drug, and a
dose of the trial drug alone. A telemetry collar was used on each fox to
monitor the duration and intensity of activity, and behaviour from dosage to
death was recorded using daylight/infra-red video cameras. In foxes dosed
with 1080 alone, a mean of 4.05 (0.86, P < 0.05) h
was observed from dosage to symptoms and 1.57 (0.46, P
< 0.05) h from symptoms to death. Diazepam reduced the overall intensity of
activity from dosage to death (P < 0.002) and from
first symptoms to death (P < 0.05). Diazepam also
extended the time until death (P < 0.01) and time
taken from dosage to first symptoms (P < 0.01). In
the dosages used, clonidine was not as effective as diazepam in reducing
activity associated with symptoms of poisoning, although it prolonged the time
taken from dosing to first symptoms (P < 0.05).
Carprofen did not significantly alter the progression of 1080 toxicosis or the
intensity of activity of foxes compared with the group that received 1080
alone. The initial symptoms of 1080 toxicosis include retching and manic
running and foxes may be more capable of suffering at this stage than after
collapse, where behaviour is likely to be associated with CNS disruption.
Diazepam may be effective in minimising any anxiety experienced by foxes
especially during the first symptoms of 1080 toxicosis.
The effectiveness of a large-scale baiting campaign and an evaluation of a buffer zone strategy for fox control
Authors: Thomson P. C. , Marlow N. J. , Rose K. , Kok N. E.
Published: January 2006

The effectiveness of a baiting campaign against red foxes
(Vulpes vulpes) was investigated in a rangeland area
near Carnarvon, Western Australia. An area of 3180 km2
was aerially baited with dried meat baits containing 3 mg 1080 poison (5 baits
km–2) in August 1995. All 45 radio-collared foxes
monitored in the area were killed by baits. More than half the radio-collared
foxes died within 3 days of baits being laid; the last surviving
radio-collared fox died 44 days after baits were laid. The overall population
reduction was estimated to be >95%. Further implications of this
high level of bait uptake are discussed in relation to immunocontraceptive
control of foxes, as well as for population reduction or vaccination of foxes
to control rabies.
Reinvasion of the baited area occurred mainly in autumn, when juvenile foxes
were dispersing. The relevance of this result is discussed in relation to
developing more effective baiting strategies. As part of another experiment,
outer sections of the baited area were periodically re-baited as a buffer zone
to reduce immigration by foxes into the central baited area; the buffer
baiting proved to be very effective in preventing recolonisation of the entire
baited area.
Field evaluation of four 1080 baits for dingo control
Authors: Eldridge S. R. , Berman D. M. , Walsh B.
Published: January 2006

Three trials were conducted to compare the effectiveness of four 1080 dingo
baits (two non-refined meat baits and two highly processed manufactured baits)
in reducing dingo activity in the Northern Territory. Baits were laid at water
points and dingo activity was estimated from track counts along a circular
path cleared around each water point before baiting, immediately after and 10
months after baiting. Significant reductions in dingo activity were observed
only at water points baited with non-refined meat baits. Highly processed
manufactured baits did not significantly affect dingo activity. Data for
non-target and dingo prey species were also recorded, but were generally
insufficient to identify any effects of baiting on these species, or any
relationships between the effectiveness of bait and the availability of prey.
It is recommended that non-refined meat baits be used in preference to highly
processed manufactured baits for the control of dingoes in the Northern
Territory.
Australian fur seals at Seal Rocks, Victoria: pup abundance by mark - recapture estimation shows continued increase
Authors: Shaughnessy P. D. , Troy S. K. , Kirkwood R. , Nicholls A. O.
Published: January 2006

The abundance of Australian fur seal pups was determined at Seal Rocks,
Westernport, Victoria in late December 1997 using a mark–recapture
procedure with repeated recapture sessions. Pups (n
= 1291) were marked by clipping the black guard hair on the head to
reveal lighter underfur. Recaptures from the whole colony were made on eight
occasions 1–3 days later. In the recapture sessions, a mean of
32% of sighted pups had been marked. Estimates of pup numbers over the
eight recapture sessions were calculated using the Petersen estimate and then
combined by taking their arithmetic mean. The combined estimate was 4024
(95% confidence range 3908–4141). In 1991–92, a similar
procedure led to an estimate of pup numbers of 2817 (95% confidence
range 2703–2930). For both breeding seasons, estimates of pup numbers
from each recapture session were also combined assuming a joint hypergeometric
distribution; there was little difference in the results from the two
procedures, although the confidence intervals for the hypergeometric mean were
smaller than those for the arithmetic mean.
From 1991–92 to 1997–98, pup numbers increased by 43%, at
an exponential rate of 0.059 (95% confidence range
0.0526–0.0664), equivalent to 6.1% per annum
(5.4–6.9%). This is greater than the rate of increase of pups at
the colony between 1968–69 and 1991–92, which was 0.023
(95% confidence range 0.0198–0.0268), equivalent to 2.4%
per annum (2.0–2.7%).
Because of the rapid rate of increase of the Australian fur seal colony at
Seal Rocks and the importance of the locality for tourism, we recommend that
the abundance of pups there be determined every 3–5 years using a
mark–recapture technique.
Controlling feral goats by shooting from a helicopter with and without the assistance of ground-based spotters
Authors: Bayne Paul , Harden Bob , Pines Ken , Taylor Ursula
Published: January 2006

The success of aerial shooting to control feral goats in arid and semi-arid
environments has lead to its widespread use in rugged and more densely
vegetated terrain elsewhere in Australia. In this experiment, the
method’s effectiveness with and without the aid of ground spotters to
assist in locating goats was evaluated in such terrain in the Chandler River
Gorge near Armidale, New South Wales. The abundance of goats was estimated by
applying a correction factor (1.45) to indices of abundance made by ground
survey. Ground observers monitored success during the cull. Overall, only
31% of an estimated 462 goats were culled, at an average cost of
$61 per goat. In all, 50% of the goats were in herds never seen
by the helicopter crew, while the remaining 19% were individuals that
escaped (17% unseen from the air) from herds that were shot at.
Inconsistent culling success, combined with marked differences in the
behaviour of goats in different experimental blocks, suggested that variable
prior exposure to aerial shooting had a significant and confounding effect on
the experimental outcome. Where goats had no prior experience of aerial
shooting, culling success was 40% without spotter assistance and
59% with spotter assistance. Where there had been a history of aerial
shooting the ground observers reported a marked increase in evasive behaviour,
and the cull was only 21% even with spotter assistance. These results
show that aerial shooting is not as successful in this type of terrain as has
been assumed and suggest that its repeated or exclusive use will result in
declining effectiveness as goats learn to evade the helicopter.
Sexual dimorphism and sex identification in the South American culpeo fox, Pseudalopex culpaeus (Carnivora : Canidae)
Authors: Travaini Alejandro , Juste Javier , Novaro Andrés J. , Capurro Angel F.
Published: January 2006

Sexual dimorphism is analysed in skulls of the culpeo fox,
Pseudalopex culpaeus, through multivariate and
univariate approaches. The species shows a moderate level of sexual dimorphism
with most cranial variables being, on average, 5% larger in males.
Equations are obtained for inferring the sex of skulls of juvenile, subadult
and adult culpeo foxes. The equations are based on a reduced set of variables
obtained from stepwise discriminant analyses by age class on skull
measurements. The discriminant power of all functions is estimated on the
basis of a jackknife reclassification procedure. Correct classification is
higher than 85% for both sexes, and is similar to, or higher than, the
values reported for other foxes. The use of the discriminant function pooling
subadult and adult skulls is rec ommended because it shows a high percentage
of correct classification without the necessity of ascribing a collected skull
to the subadult or adult age class before sex estimation. The equations
provide an easy method to estimate the sex ratio of wild populations of this
furbearer species using the abundant carcasses discarded throughout
north-western Patagonia as a result of the intense hunting of the species. The
information on sex ratios will help in the study of population dynamics and
when monitoring the harvest of culpeo foxes.
Models of the distribution and abundance of ground-dwelling mammals in the eucalypt forests of north-eastern New South Wales in relation to habitat variables
Authors: Catling P. C. , Burt R. J. , Forrester R. I.
Published: January 2006

We examined the distribution and abundance of ground-dwelling mammals in
eucalypt forests in relation to habitat variables within an area of
c. 24 000 km2 in north-eastern New
South Wales. Habitat variables are defined as vegetative variables that may be
altered or created by humans or natural disturbances and used for the
management and/or conservation of fauna. Statistical models of the
distribution and abundance of ground-dwelling mammals in relation to the
habitat variables are presented.
Generally, the ground-dwelling mammals in the region were more diverse and in
greater abundance, and the forest more complex, than in south-eastern New
South Wales. The models reflect a general preference of the ground-dwelling
fauna for forests that were least disturbed. However, some species were more
tolerant of disturbance than others.
Recent developments in remote sensing have allowed the mosaic of habitats for
ground-dwelling mammals to be mapped over large areas of the landscape. Such
maps and the models presented here are discussed with respect to the
management of wildlife species. The reduced disturbance during silvicultural
practices and the lower abundance of foxes are discussed in relation to the
greater diversity and abundance of the ground-dwelling mammals in the region
than in south-eastern New South Wales.
Effects of the Iron Baron oil spill on little penguins (Eudyptula minor). II. Post-release survival of rehabilitated oiled birds
Authors: Goldsworthy S. D. , Giese M. , Gales R. P. , Brothers N. , Hamill J.
Published: January 2006

The post-release survival of rehabilitated oiled little penguins
(Eudyptula minor) was monitored over 20 months following
the Iron Baron oil spill (10 July 1995) in northern
Tasmania, Australia. During rehabilitation, over 1800 little penguins were
individually banded and detailed records kept of factors including their
degree of oiling, sex, capture and release mass and capture and release
condition. Post-release survival of rehabilitated oiled little penguins was
assessed through regular trapping of birds over two breeding sites (Ninth
Island and Low Head). The minimum estimate of post-release survival was
59% for penguins from Ninth Island and 44% for penguins from Low
Head. Rehabilitated oiled little penguins had significantly lower survival
than non-oiled birds at both sites. The main factor affecting post-release
survival was the extent of oiling, which itself had a significant influence on
the capture mass and condition of birds. Combined, these factors had the
greatest power to predict post-release survival. Other factors that
significantly affected post-release survival included release mass and
condition, and the sex of the bird. The duration of rehabilitation and whether
birds were translocated (200–410 km) from their capture site prior to
release did not significantly affect survival. The results of this study
indicate how aspects of oiling, the condition of birds and rehabilitation
affect post-release survival. As such, they will help improve the success of
wildlife rehabilitation in future spills, and highlight the importance of
individually marking rehabilitated oiled wildlife and post-release monitoring
in assessing the success of rehabilitation programs.
Effects of the Iron Baron oil spill on little penguins (Eudyptula minor). III. Breeding success of rehabilitated oiled birds
Authors: Giese M. , Goldsworthy S. D. , Gales R. , Brothers N. , Hamill J.
Published: January 2006

The long-term effects of oiling on the breeding success of rehabilitated oiled
little penguins (Eudyptula minor) were examined over two
consecutive breeding seasons following the Iron Baron
oil spill in 1995. The commencement of egg laying was delayed among
rehabilitated oiled penguins compared with non-oiled birds during the
1995/96 breeding season. During that season, hatching success (number of
eggs hatched from those laid) was no different in nests containing
rehabilitated oiled penguins than in those containing non-oiled birds, but
overall egg success (number of pre-fledging chicks from the number of eggs
laid) was significantly lower among rehabilitated oiled birds. This effect was
predominant in nests containing a rehabilitated oiled female, where the
probability of successfully fledging any chicks was 22% lower than in
nests containing a non-oiled female. During the 1996/97 breeding season,
there was no significant difference between either the hatching or egg success
of rehabilitated oiled penguins and non-oiled birds. In both seasons, the
pre-fledging masses of chicks from rehabilitated oiled penguins were
significantly lower than those from non-oiled birds. The chicks of
rehabilitated oiled penguins were therefore expected to have lower survival
than chicks raised by non-oiled parents. Results indicate that oiling not only
reduced the number of chicks raised by rehabilitated oiled penguins in the
short term, but also decreased the quality of young produced for at least two
seasons following the spill.
Detecting sperm on the perivitelline membrane of incubated turkey eggs and its implications for research on fertility problems in endangered species
Authors: Small Angus O. , Schlusser Kira , Ryan Christine J. , Jamieson Ian G.
Published: January 2006

A method whereby sperm nuclei on the perivitelline membrane are stained and
counted under a photomicroscope has been used extensively in the poultry
industry to show a correlation between egg infertility and low numbers of
spermatozoa near the site of fertilisation. It has been suggested that this
method could also be potentially useful for assessing infertility problems in
endangered species. For poultry, the staining technique is normally applied to
fresh (i.e. unincubated) eggs, but conservation managers normally collect eggs
for examination only after they have been incubated for several days and then
assessed (by candling) to lack a developing embryo. Whether sperm would
persist on the perivitelline membrane of infertile eggs incubated over several
days is not known. In relation to our research on egg infertility in the
endangered takahe (Porphyrio hochstetteri), we examined
the above problem by comparing sperm counts on the membrane of fresh versus
incubated infertile eggs from artificially inseminated domestic turkey
(Meleagris gallopavo). We were able to detect sperm in
most infertile eggs that had not been incubated, but no sperm at all were
detected in infertile eggs that were incubated for seven days, suggesting that
warming of the eggs may cause the sperm on the membrane to degrade. The
inherent fragility of avian sperm nuclei may limit the usefulness of this
technique for assessing infertility in takahe and other species where failed
(non-developing) eggs are not removed from the nest until after a short period
of incubation.
Breeding biology of captive, reintroduced and wild greater bilbies, Macrotis lagotis (Marsupialia : Peramelidae)
Authors: Southgate R. I. , Christie P. , Bellchambers K.
Published: January 2006

The breeding biology and growth of Macrotis lagotis was
investigated using captive stock in Alice Springs and Dubbo and a reintroduced
population at Watarrka National Park. Individuals of
M. lagotis reached sexual maturity at about six months
of age and continued growing until about 18 months old. Pouch life and weaning
took approximately 90 days and females produced up to four litters per year.
Litters comprised 1–3 young. Average litter size at pouch exit ranged
from 1.0 to 1.88, depending on whether animals were studied in captivity or
under reintroduced free-range conditions. Females commonly continued breeding
past the age of four years and longevity extended to 10 years in captivity. In
comparison, the most animals caught in the wild were estimated to be less than
12 months old. Animals in the reintroduced population exhibited a greater
reproductive output than the captive populations examined. However,
survivorship was far greater for animals in captivity. An intensively managed
captive population may achieve a three-fold increase in size in a 12-month
period.
Introduction: Carnivorous marsupials
Authors: Jones Menna , Dickman Chris
Published: January 2006

Population dynamics and movements were investigated in a population of
Pseudantechinus macdonnellensis, a dasyurid marsupial
occupying rocky habitats in the Australian arid zone. Intra-annual cycling in
abundance, activity and numbers of resident and transient individuals was not
regular from year to year, although the number of residents was high compared
with the number of transients. Juvenile recruitment varied between years and
was as low as 18%. Densities were low (0.05–0.2
ha–1 for females and 0.05–0.3
ha–1 for males), and individuals exhibited large
stable long-term ranges – mean Minimum Convex Polygon (MCP) area for
males was 427 m2 and for females 171
m2. The constraints of the monoestrous, synchronised
reproductive strategy of P. macdonnellensis, together
with the ameliorating effect of its rocky habitat, which may decrease food
limitation and increase survival, seem to have produced a different pattern of
population dynamics to that seen in arid-zone dasyurids that are polyoestrous
plains-dwellers. The patterns of movement in
P. macdonnellensis also differ from plains-dwelling
species, in which individuals display high life-time mobility. The existence
of large but non-drifting ranges in P. macdonnellensis
may be seen as a consequence of a low but relatively predictable food supply,
which precludes the necessity for individuals to shift their activity to
temporary patches of high food supply, but requires them to occupy a large
range to obtain enough food to meet energy requirements.
Abundance and recruitment patterns of the trilling frog (Neobatrachus centralis) in the Australian arid zone
Authors: Read J. L.
Published: January 2006

Maximum capture rates of Neobatrachus centraliswere up
to an order of magnitude higher than those of the most abundant lizard species
sampled at Olympic Dam in the South Australian arid zone from 1986 to 1997.
Although common in most habitats, densities of
N. centralis were greatest at sites adjacent to dunes or
swamps. Breeding was restricted to summer months, and widespread recruitment
occurred in only three of the 11 years. Metamorphosis occurred in as little as
17 days in short-lived swamps, but was delayed for up to nine months in less
temporary ponds.
Temporal patterns of drinking in the tammar wallaby (Macropus eugenii Desmarest)
Authors: Lentle R. G. , Stafford K. J. , Potter M. A. , Springett B. P. , Haslett S.
Published: January 2006

The temporal association between drinking and feeding in four captive tammar
wallabies (Macropus eugenii Desmarest) maintained on
various foods is examined. Tammars maintained on cubed carrots never drank. In
tammars fed pellets food-associated drinking took place and 77.5% (7.4,
s.e.) of drinking episodes commenced within 60 s of the beginning or end of a
feeding event. Drinking events occurred singly, were of short duration and
increased in frequency but not duration, when low-quality pellets were fed.
Food- associated drinking in the tammar may result from the induction of
drinking episodes of relatively fixed duration by an oropharyngeal reflex.