Longevity in wild populations of the squirrel glider Petaurus norfolcensis.

2006 ◽  
Vol 28 (2) ◽  
pp. 239 ◽  
Author(s):  
R. van der Ree ◽  
M. J. Harper ◽  
M. Crane

Petaurus norfolcensis were trapped between December 1996 and April 2005 at 3 sites in south-eastern Australia. In 2005 nine individuals marked in previous years were captured. Age estimates at first capture were based on body mass, tooth wear and pouch condition. Most recaptured individual were propertly assigned to the correct age category (>3 years), but the age of 2 were underestimated. This indicates uncertainty in using physical characteristics, chiefly wear of upper incisors, to estimate age in P. norfolcensis.One individual captured in 2005 was over 7 years 9 months old. This compares to captive P. breviceps and P. australis records of 9 years and 16 years respectively.

2002 ◽  
Vol 29 (4) ◽  
pp. 329 ◽  
Author(s):  
Rodney van der Ree

The geographic range of the squirrel glider (Petaurus norfolcensis) in south-eastern Australia largely corresponds with fertile soils highly suited for agriculture. As a consequence of extensive clearing for agriculture, the conservation of P. norfolcensis in south-eastern Australia is now reliant on a mosaic of many fragmented and isolated patches of woodland and forest. In this study, I investigated the population dynamics of P. norfolcensis in an agricultural landscape where most remnant woodland occurs as linear strips along roadsides, unused road reserves and watercourses. A total of 251 gliders were trapped 1343 times within the linear habitats between December 1996 and November 1998. Gliders were resident within the linear strips at 0.95–1.54 individuals ha–1, a density equal to, or greater than, that recorded elsewhere for the species in continuous forest. All adult females were reproductively active and the mean natality rate was 1.9 young per adult female per year. Overall, the population age-structure appeared to be stable. While currently supporting a stable, high-density population, the long-term viability of these remnants as habitat is not assured because roadside reserves are narrow, easily fragmented and subjected to a host of deleterious processes causing ongoing habitat loss and degradation.


2005 ◽  
Vol 32 (2) ◽  
pp. 151 ◽  
Author(s):  
Clive A. Marks ◽  
Rebecca Wilson

Meat-based baits are currently used for the control of the exotic red fox (Vulpes vulpes) in south-eastern Australia. Thirty-one quadrupedal endemic mammals are considered to be potentially bait consuming (PBC) and may be exposed to bait toxicants. Mechanical toxicant ejectors may be more selective if some PBC species cannot apply enough upward force to trigger them. A simple relationship between body mass and pulling force was sought to enable estimates of ejector specificity to be made. The pulling force applied to ejector baits was measured for the red fox and six endemic mammals. The relationship between body mass and pulling force was highly significant (P < 0.001) and the resulting regression equation was used to estimate the highest pulling forces for 31 quadrupedal mammals based upon the largest body mass recorded for each species. In a sample of 640 foxes, taken by a range of methods in south-eastern Australia, the lowest adult body mass detected from January to September was 3 kg and declined only when cubs were present in the population from October to December. An ejector trigger force of 26.46 N was estimated to allow foxes weighing >3 kg to trigger the device, while eliminating exposure of 26 of the 31 PBC mammals. Appropriate toxicant selection and dose rates may ensure that four out of five susceptible mammals are less likely to be affected by unwanted exposure.


1995 ◽  
Vol 43 (1) ◽  
pp. 31 ◽  
Author(s):  
K Breuer ◽  
A Lill ◽  
J Baldwin

Haematological parameters and body mass of four passerine bird species resident in south-eastern Australia were compared in winter and summer to determine whether there were changes indicative of metabolic adjustments associated with seasonal acclimatisation. Haematocrit and whole-blood haemoglobin content did not change seasonally, but erythrocyte numbers increased (by 45-72%) and erythrocyte volume decreased (by 40-73%) significantly in winter in all species. The greater surface area to volume ratio and shorter diffusion pathway of smaller erythrocytes in winter should enhance blood oxygen transport efficiency and thus potentially facilitate metabolic acclimatisation to cold stress. Only one species showed a significant, but small (3%), increase in body mass in winter, suggesting only a minor role for winter fattening in any such seasonal metabolic adjustments in the species studied. The findings contrast with those for some passerines overwintering in the north temperate zone, but the generality of these possible north-south differences needs further investigation.


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