Movements, dens and feeding behaviour of the tropical scaly-tailed possum (Wyulda squamicaudata)

1999 ◽  
Vol 26 (3) ◽  
pp. 367 ◽  
Author(s):  
Myfanwy J. Runcie

I used trapping and radio-telemetry to study a population of scaly-tailed possums (Wyulda squamicaudata) in the Kimberley region of Western Australia. Radio-tracking of five adults over eight days provided detailed information on dens, and on size and shape of the home range, and facilitated nocturnal observations. W. squamicaudata used four different types of rock formations for diurnal dens: rockpiles, sunken rockpiles, large rock slabs and underground rock crevices. Radio-tagged possums of both sexes nested alone, used multiple dens and had overlapping home ranges. Both tagged and untagged possums appeared to be solitary and foraged alone. The average size of the home range was 1.0 ha (range 0.03–2.0 ha). Estimates of density ranged from 2.3 to 4.6 possums per hectare. Scaly-tailed possums fed on leaves of four species of trees (Xanthostemon eucalyptoides, X. paradoxus, Eucalyptus spp., and Planchonia careya) as well as the flowers and seeds of a perennial herb (Trachymere didiscordis). Feeding in trees is aided by the rough scaly tail, which sometimes supports the possum’s full body weight. At this study site W. squamicaudata is sympatric with the rock-haunting possum (Petropseudes dahli), and they may compete for food and den resources.

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.


Author(s):  
Rafael Mares ◽  
Ricardo S. Moreno ◽  
Roland W. Kays ◽  
Martin Wikelski

Home range shifts prior to natal dispersal have been rarely documented, yet the events that lead a subadult to abandon a portion of its home range and venture into unfamiliar territories, before eventually setting off to look for a site to reproduce, are probably related to the causes of dispersal itself. Here, we used a combination of manual radio-tracking and an Automated Radio Telemetry System to continuously study the movements of a subadult male ocelot (Leopardus pardalis), a solitary carnivore with sex-biased dispersal, on Barro Colorado Island, Panama, for 18 months from May 2003 through October 2004. The subadult ocelot?s parents were also radio-tracked to record possible parent-offspring interactions within their home ranges. At the age of ca. 21 months the subadult gradually began to shift its natal home range, establishing a new one used until the end of the study, in an area that had previously been used by another dispersing subadult male. Only three parent-offspring interactions were recorded during the four months around the time the range-shift occurred. The apparent peaceful nature of these encounters, along with the slow transition out of a portion of his natal home range, suggest the subadult was not evicted from his natal area by his parents. The timing of the shift, along with the subadult?s increase in weight into the weight range of adult ocelots four months after establishing the new territory, suggests that predispersal home range shifts could act as a low risk and opportunistic strategy for reaching adult size, while minimizing competition with parents and siblings, in preparation for an eventual dispersal into a new breeding territory.


Diversity ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 100 ◽  
Author(s):  
Priscila da Silva Lucas ◽  
Milene Alves-Eigenheer ◽  
Talitha Mayumi Francisco ◽  
James M. Dietz ◽  
Carlos Ramón Ruiz-Miranda

Linear infrastructures are a primary driver of economic development. However, they also can negatively affect wildlife by mortality and the barrier effect. In this paper, we address how paved and unpaved roads, high-tension power lines, and gas/oil pipelines affect home range size, core areas, and movement in an endangered primate, the golden lion tamarin (GLT). Location data were recorded using radio telemetry on 16 groups in two protected areas and in privately owned forest fragments. The GLT’s home range, not core area, increased in size for the groups that occupied locations far from linear infrastructures; home range was also significantly influenced by available forest size. None of the home ranges contained a road, but home ranges did contain power lines. GLTs used the surrounding landscape near all types of infrastructure. Movement analysis showed that most of the step lengths (distances between subsequent locations) were less than 100 m between two consecutive locations, but step length was longer for roads and longer for groups in fully forested habitats. Tamarins avoided paved roads when in close proximity to this type of infrastructure; this behavior increased in areas without adequate adjacent forest habitat. Our results show that linear infrastructures differ in their level of impact: roads can act as a barrier, whereas other types of infrastructure have minimal effect on movement and home range. We discuss these differences in impact in terms of structure, maintenance schedules, and edge effects of infrastructure.


2007 ◽  
Vol 34 (3) ◽  
pp. 177 ◽  
Author(s):  
Robyn F. Wilson ◽  
Helene Marsh ◽  
John Winter

Roads and powerline corridors destroy canopy connectivity in the rainforest of north-east Australia. We tested the hypotheses that linear barriers affect (a) the alignment of home ranges, (b) use of habitat either side of linear barriers, and (c) the crossing of them by the strictly arboreal lemuroid ringtail possum (Hemibelideus lemuroides), which is known to be vulnerable to habitat fragmentation. Radio-tracking and a translocation experiment were conducted at a narrow 7-m-wide road and an 80-m-wide powerline. Homes ranges of lemuroid ringtails ranged from 0.15 to 1.67 ha (minimum convex polygon) and were aligned with the road but not powerline corridors. When lemuroid ringtails were experimentally translocated, wider canopy clearings over roads reduced their capacity to return to their original home range, and the powerline corridor was a nearly insurmountable barrier. No possums were observed crossing roads or the powerline corridor at ground level or residing in the intervening matrix, indicating that loss of canopy connectivity has a negative impact on their movements.


2015 ◽  
Vol 42 (5) ◽  
pp. 437 ◽  
Author(s):  
Javan M. Bauder ◽  
David R. Breininger ◽  
M. Rebecca Bolt ◽  
Michael L. Legare ◽  
Christopher L. Jenkins ◽  
...  

Context Despite the diversity of available home range estimators, no single method performs equally well in all circumstances. It is therefore important to understand how different estimators perform for data collected under diverse conditions. Kernel density estimation is a popular approach for home range estimation. While many studies have evaluated different kernel bandwidth selectors, few studies have compared different formulations of the bandwidth matrix using wildlife telemetry data. Additionally, few studies have compared the performance of kernel bandwidth selectors using VHF radio-telemetry data from small-bodied taxa. Aims In this study, we used eight different combinations of bandwidth selectors and matrices to evaluate their ability to meet several criteria that could be potentially used to select a home range estimator. Methods We used handheld VHF telemetry data from two species of snake displaying non-migratory and migratory movement patterns. We used subsampling to estimate each estimator’s sensitivity to sampling duration and fix rate and compared home range size, the number of disjunct volume contours and the proportion of telemetry fixes not included in those contours among estimators. Key Results We found marked differences among bandwidth selectors with regards to our criteria but comparatively little difference among bandwidth matrices for a given bandwidth selector. Least-squares cross-validation bandwidths exhibited near-universal convergence failure whereas likelihood cross-validation bandwidths showed high sensitivity to sampling duration and fix rate. The reference, plug-in and smoothed cross-validation bandwidths were more robust to variation in sampling intensity, with the former consistently producing the largest estimates of home range size. Conclusions Our study illustrates the performance of multiple kernel bandwidth estimators for estimating home ranges with datasets typical of many small-bodied taxa. The reference and plug-in bandwidths with an unconstrained bandwidth matrix generally had the best performance. However, our study concurs with earlier studies indicating that no single home range estimator performs equally well in all circumstances. Implications Although we did not find strong differences between bandwidth matrices, we encourage the use of unconstrained matrices because of their greater flexibility in smoothing data not parallel to the coordinate axes. We also encourage researchers to select an estimator suited to their study objectives and the life history of their study organism.


2000 ◽  
Vol 27 (2) ◽  
pp. 117 ◽  
Author(s):  
Murray Efford ◽  
Bruce Warburton ◽  
Nick Spencer

Common brushtail possums (Trichosurus vulpecula) are intractable pests in New Zealand. The effectiveness of local control can be limited by immigration, some of which has been attributed to a ‘vacuum effect’ – directed movements induced by the control itself. To characterise the vacuum effect we examined changes in the home ranges of trapped possums following control in a 6-ha block at one end of a 13-ha forest patch on farmland near Dunedin, New Zealand. We also monitored a sample of possums by radio-telemetry. After control, the density was 3 ha–1 inside the removal area and 16 ha–1 outside. During the year after the removal, 29% of possums within 100 m of the boundary of the removal area (n = 38) shifted their range centre at least 50 m towards it. The effect diminished rapidly with distance: only 1 of 28 animals moved more than 200 m from the boundary. The size of the previous range was a significant predictor of movement among males, but this may be partly a sampling artifact. We measured a net flux of 69 possums km–1 across the boundary in the 12 months after control, and possums settled on average 44 6.9 m inside the boundary. The vacuum effect in brushtail possums appears largely confined to home-range adjustments by individuals with ranges overlapping the area of reduced density. This limits its potential role in population recovery.


1996 ◽  
Vol 23 (5) ◽  
pp. 547 ◽  
Author(s):  
M Evans

Home ranges and movement schedules of sympatric bridled nailtail wallabies, Onychogalea fraenata, and black-striped wallabies, Macropus dorsalis, were studied during wet and dry seasons by radio-tracking. Home ranges of black-striped wallabies (91 ha) were much larger than those of bridled nailtail wallabies (40 ha). Home-range size differed between sexes for bridled nailtail wallabies (males, 59 ha; females, 26 ha), but not for black-striped wallabies. Intraspecific seasonal differences in home-range size were not significant. All home ranges included diurnal shelter habitat, although the preferred type of shelter habitat was different for each species. Movement schedules differed significantly between wet and dry seasons for black-striped wallabies (which made a higher frequency of longer-distance movements during the dry season than during the wet season), but not for bridled nailtail wallabies.


2004 ◽  
Vol 31 (3) ◽  
pp. 327 ◽  
Author(s):  
Helen Puckey ◽  
Milton Lewis ◽  
David Hooper ◽  
Carrie Michell

Radio-telemetry was used to examine the home range, movement and habitat utilisation of the critically endangered Carpentarian rock-rat (Zyzomys palatalis) in an isolated habitat patch in the Gulf of Carpentaria hinterland over a 13-month period. Two home-range estimators were used in the study, (i) minimum convex polygon (MCP) and (ii) fixed Kernel (KL), the latter also being used to estimate core areas of activity. Based on a total sample size of 21 individuals, the mean MCP home range was 11 165 m2, similar to the mean KL home range of 10 687 m2. Core areas were, on average, 11.9% of the KL home-range estimate. There was no significant difference in the size of home range or core area of males and females. Juveniles had a significantly smaller home range than adults. Home ranges and, to a lesser degree, core areas were non-exclusive, with multiple areas of overlap (averaging 41% and 38% respectively) within and between all age and gender categories, but especially between males and between juveniles. Movement frequencies showed that animals made many short forays in a central area close to the arithmetic home-range mean and far fewer long forays of distances greater than 100 m from the central area. The spatial and temporal activity of Z. palatalis was concentrated in, but not confined to, the 'valley' and 'slope' habitats, with fewer movements of rats onto the surrounding 'plateau'. Resource selection analyses showed that Z. palatalis tended to prefer valley and slope habitats over the plateau and that the proportion of point locations was significantly higher for adults in the slope habitat and for juveniles in the valley habitat. Most home ranges were centred on the ecotone between these two habitat types. Although isolated and spatially limited, these habitat patches provide high-quality resources for dense populations of Z. palatalis. This study exemplifies a species' attempt to make efficient use of a limited resource in an otherwise hostile environment. Even small declines in habitat area or quality due to their vulnerability to fire would impact upon many animals.


2021 ◽  
pp. 317-328
Author(s):  
David J. Germano ◽  
Galen B. Rathbun ◽  
Lawrence R. Saslaw ◽  
Brian L. Cypher

The San Joaquin antelope squirrel (Ammospermophilus nelsoni) is one of five species in the genus and has the most restricted range of the four mainland antelope squirrels, occurring only in the San Joaquin Desert of California. Despite being state-listed as Threatened since 1980, few studies have been conducted on A. nelsoni, especially ecological studies, which hampers recovery efforts. We conducted a radio-telemetry study in 2002 of 19 males on the Lokern Natural Area in the southwestern portion of the San Joaquin Desert. Based on 100% Minimum Convex Polygons (MCP), home ranges varied from 1.25–14.5 ha with a mean of 5.93 ha (± 0.90 standard error). The average daily distance traveled by these 19 males was 128.5 m (range, 71.4–224.5) and the average greatest distance travelled in a day was 313.0 m, with some traveling > 0.5 km. Our data are useful to further refine the estimates of home range and movements of this neglected protected species, but in the future, better home range studies are needed that span multiple years, include both sexes, and occur at sites across its range.


2003 ◽  
Vol 30 (4) ◽  
pp. 339 ◽  
Author(s):  
Pip Masters

Information on the movements, social structure and burrow use of the mulgara, Dasycercus cristicauda, was collected using radio-telemetry at two study areas in central Australia, one located near the Granites gold mine in the Tanami Desert and the other located on the edge of Uluru Kata Tjuta National Park. The average home-range size was not significantly different between the two study areas but home-range size was highly variable amongst individuals, with areas from 1.0 to 14.4 ha being used. The average maximum distance moved was significantly greater for males than for females. Overlap of home ranges was less than 20%, on average, but this was highly variable. There was an average overlap of 14% for females, with a maximum of 67%. The home ranges of males also overlapped, averaging 16.5%, as did those of females and males (19%). D. cristicauda is a solitary species that exhibits high site fidelity and a low propensity for dispersal once a home range has been established.


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