Juvenile behaviour and dispersal of chuditch (Dasyurus geoffroii) (Marsupialia : Dasyuridae)

2000 ◽  
Vol 48 (5) ◽  
pp. 551 ◽  
Author(s):  
Todd R. Soderquist ◽  
Melody Serena

We examined the dispersal chronology and movement patterns of wild juvenile chuditch (Dasyurus geoffroii) using radio-tracking and trapping. Juveniles first began exploring outside the natal den when 17 weeks old and rapidly increased their foraging duration and distance. By the time weaning was completed during Weeks 22–24, at least 6 h was devoted to the initial foraging bout and juveniles were travelling over 500 m from their dens each night. The initial phase of dispersal occurred soon after weaning, with juveniles denning separately from their mothers yet remaining in the maternal home range. Mothers sometimes instigated this phase by abandoning their litters in the natal den. The second phase of dispersal away from the natal area was strongly male-biased, occurring when juveniles were 25 weeks old on average and covering long distances (>10 km). Most females were philopatric or settled in vacant areas near the maternal home range. Observation of captive chuditch during the weaning period provided further insights on dispersal, indicating that social play among littermates may be an important factor at this time. Aggressive wrestling rapidly escalated during the initial weeks of weaning, when wild juveniles were active yet in close proximity for most of the night. The intensity of wrestling declined before weaning was complete. Wild juveniles apparently participated in similar wrestling bouts, although possibly on a more limited scale than captives. This play behaviour potentially facilitates social cohesion among the litter at a time when juveniles are first capable of harming each other, and provides practice for fighting techniques used by adults to defend territories and secure mates.

2021 ◽  
Author(s):  
Halina Teresa Kobryn ◽  
Edward J. Swinhoe ◽  
Philip W. Bateman ◽  
Peter J. Adams ◽  
Jill M. Shephard ◽  
...  

Abstract The red fox (Vulpes vulpes) is one of the most adaptable carnivorans, thriving in cities across the globe. Understanding movement patterns and habitat use by urban foxes will assist with their management to address wildlife conservation and public health concerns. Here we tracked five foxes across the suburbs of Perth, Western Australia. Three females had a core home range (50% kernel density estimate; KDE) averaging 37 ± 20 ha (range 22–60 ha) or a 95% KDE averaging 174 ± 130 ha (range 92–324 ha). One male had a core home range of 95 ha or a 95% KDE covering 352 ha. The other male covered an area of ~ 4 or ~ 6 times this: having a core home range of 371 ha or 95% KDE of 2,062 ha. All five foxes showed statistically significant avoidance of residential locations and significant preference for parkland. Bushland reserves, golf courses, and water reserves were especially preferred locations. Foxes moved quickest (i.e. commuting) when they were in close proximity to roads and slowest (i.e. foraging) when they were further from roads. We compare these findings with a review of the literature for urban fox home ranges. The movement patterns we describe are likely to be common for urban foxes, with half of the published home range estimates for urban foxes (principally based on VHF data) excluding data for ‘lost’ individuals or animals that showed ‘excursions’. It is likely that the home range estimates for these urban exploiters have therefore been grossly underestimated to date. Further application of GPS trackers that allow remote download will vastly improve our understanding of the space use of urban foxes.


2009 ◽  
Vol 36 (5) ◽  
pp. 422 ◽  
Author(s):  
K. E. Moseby ◽  
J. Stott ◽  
H. Crisp

Control of introduced predators is critical to both protection and successful reintroduction of threatened prey species. Efficiency of control is improved if it takes into account habitat use, home range and the activity patterns of the predator. These characteristics were studied in feral cats (Felis catus) and red foxes (Vulpes vulpes) in arid South Australia, and results are used to suggest improvements in control methods. In addition, mortality and movement patterns of cats before and after a poison-baiting event were compared. Thirteen cats and four foxes were successfully fitted with GPS data-logger radio-collars and tracked 4-hourly for several months. High intra-specific variation in cat home-range size was recorded, with 95% minimum convex polygon (MCP) home ranges varying from 0.5 km2 to 132 km2. Cat home-range size was not significantly different from that of foxes, nor was there a significant difference related to sex or age. Cats preferred habitat types that support thicker vegetation cover, including creeklines and sand dunes, whereas foxes preferred sand dunes. Cats used temporary focal points (areas used intensively over short time periods and then vacated) for periods of up to 2 weeks and continually moved throughout their home range. Aerial baiting at a density of 10 baits per km2 was ineffective for cats because similar high mortality rates were recorded for cats in both baited and unbaited areas. Mortality was highest in young male cats. Long-range movements of up to 45 km in 2 days were recorded in male feral cats and movement into the baited zone occurred within 2 days of baiting. Movement patterns of radio-collared animals and inferred bait detection distances were used to suggest optimum baiting densities of ~30 baits per km2 for feral cats and 5 per km2 for foxes. Feral cats exhibited much higher intra-specific variation in activity patterns and home-range size than did foxes, rendering them a potentially difficult species to control by a single method. Control of cats and foxes in arid Australia should target habitats with thick vegetation cover and aerial baiting should ideally occur over areas of several thousand square kilometres because of large home ranges and long-range movements increasing the chance of fast reinvasion. The use of temporary focal points suggested that it may take several days or even weeks for a cat to encounter a fixed trap site within their home range, whereas foxes should encounter them more quickly as they move further each day although they have a similar home-range size. Because of high intra-specific variability in activity patterns and home-range size, control of feral cats in inland Australia may be best achieved through a combination of control techniques.


1996 ◽  
Vol 23 (6) ◽  
pp. 755 ◽  
Author(s):  
KA Handasyde ◽  
RW Martin

Habitat utilisation and foraging behaviour by the common striped possum (Dactylopsila trivirgata) was investigated by means of spotlighting and radio-tracking at Shiptons Flat, far north Queensland. Vine forest was the primary habitat of D. trivirgata; however, animals were also observed in open eucalypt (Eucalyptus tereticornis) woodland. Information collected on foraging behaviour suggests that D. trivirgata are generalist insectivores consuming some fruit and other foodstuffs, such as honey. Radio-tracking data were used to calculate the home-range areas of two subadult males. The home range of the smaller male (body weight 290 g) was 5.2 ha (by the 95% harmonic mean (HM) method) or 6.5 ha (by the minimum convex polygon (MCP) method), and that of the larger male (body weight 415 g) was 21.2 ha (95% HM) or 21.3 ha (MCP). Large trees with hollows, which are utilized for denning, appear to be an important feature of the habitat for this species. D. trivirgata exhibits a pronounced degree of sociality and may breed seasonally. Observations suggest that amethystine pythons (Morelia amethistina) may be major predators of D. trivirgata at Shiptons Flat.


Koedoe ◽  
1990 ◽  
Vol 33 (2) ◽  
Author(s):  
I.L. Rautenbach ◽  
M.B. Fenton ◽  
A.C. Kemp ◽  
S.J. Van Jaarsveld

Winter radio-tracking of three African goshawks Accipiter tachiro showed that they each occupied well-wooded home ranges of at least 28 hectares. They perched and roosted mainly within densely foliaged trees and an adult female changed perches on average 4,7 times per hour. No crepuscular predation of bats was recorded, in contrast to regular summer predation on colonies of little free-tailed bats, Tadarida pumila, but winter emergence rates of these bats at dusk had dropped to < 5 of the previous summer. We predict that many accipiters will be regular predators of bats and that skewed sex ratios and high fecundity may be two means by which bats counter this predation.


2015 ◽  
Vol 308 (1) ◽  
pp. L1-L10 ◽  
Author(s):  
Bo Lan ◽  
Linhong Deng ◽  
Graham M. Donovan ◽  
Leslie Y. M. Chin ◽  
Harley T. Syyong ◽  
...  

Smooth muscle contraction can be divided into two phases: the initial contraction determines the amount of developed force and the second phase determines how well the force is maintained. The initial phase is primarily due to activation of actomyosin interaction and is relatively well understood, whereas the second phase remains poorly understood. Force maintenance in the sustained phase can be disrupted by strains applied to the muscle; the strain causes actomyosin cross-bridges to detach and also the cytoskeletal structure to disassemble in a process known as fluidization, for which the underlying mechanism is largely unknown. In the present study we investigated the ability of airway smooth muscle to maintain force after the initial phase of contraction. Specifically, we examined the roles of Rho-kinase and protein kinase C (PKC) in force maintenance. We found that for the same degree of initial force inhibition, Rho-kinase substantially reduced the muscle's ability to sustain force under static conditions, whereas inhibition of PKC had a minimal effect on sustaining force. Under oscillatory strain, Rho-kinase inhibition caused further decline in force, but again, PKC inhibition had a minimal effect. We also found that Rho-kinase inhibition led to a decrease in the myosin filament mass in the muscle cells, suggesting that one of the functions of Rho-kinase is to stabilize myosin filaments. The results also suggest that dissolution of myosin filaments may be one of the mechanisms underlying the phenomenon of fluidization. These findings can shed light on the mechanism underlying deep inspiration induced bronchodilation.


2017 ◽  
Vol 68 (8) ◽  
pp. 1454 ◽  
Author(s):  
R. D. Pillans ◽  
R. C. Babcock ◽  
D. P. Thomson ◽  
M. D. E. Haywood ◽  
R. A. Downie ◽  
...  

Large mobile herbivorous fish that specialise in browsing large brown algae are particularly important on coral reefs because their activities mediate algal–coral competition. Despite this important ecological role, we have a poor understanding of the movement patterns of such large herbivorous fish, including Kyphosus bigibbus. Nineteen K. bigibbus captured near adjacent but distinct patch reefs were tagged with internal acoustic tags and their movements monitored for up to 20 months by an array of 60 acoustic receivers. Home-range estimates showed that movements of individuals from each patch reef encompassed different spatial extents and resulted in differences in habitat used by the two groups of fish. The average 50 and 95% kernel utilisation distribution for long-term resident fish was 0.27±0.03 and 1.61±0.30km2 respectively, ranges that represent the largest values for a herbivorous coral reef fish recorded to date. There was a significantly higher degree of fidelity among fish from the same school, and to particular patch reefs, despite the proximity of the reefs and substantial overlap between schools of conspecifics. A coefficient of sociality was used on pairs of fish and showed that there was no evidence that individuals were consistently detected together when they were detected by receivers away from their home reef. The variability of movement patterns among individuals of K. bigibbus results in an increased niche footprint for this important browser, potentially increasing reef resilience.


1987 ◽  
Vol 68 (1) ◽  
pp. 173-176 ◽  
Author(s):  
M. E. Sunquist ◽  
S. N. Austad ◽  
F. Sunquist

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