Time budget of the squirrel glider (Petaurus norfolcensis) in subtropical Australia

2018 ◽  
Vol 66 (4) ◽  
pp. 251
Author(s):  
David J. Sharpe ◽  
Ross L. Goldingay
Keyword(s):  
Full Moon ◽  
Time Budget ◽  
Observation Time ◽  
Foraging Efficiency ◽  
Feeding Rates ◽  
High Quality ◽  
Food Items ◽  
Squirrel Glider ◽  
Tree Hollow ◽  
Subtropical Australia

Exudivorous mammals exploit food items of high quality and high rates of renewal, offset by wide dispersion and variable availability. How this influences foraging effort and size-related foraging efficiency remains poorly described. We examined the time budget of 5–6 male and 5–6 female squirrel gliders (Petaurus norfolcensis) during 6–8 nights in each of three seasons that were stratified by moon phase. Radio-collared gliders were observed during a series of 1-h focal observations from dusk until dawn. Feeding dominated the time budget, accounting for 78% of observation time, or 85% of time when combined with behaviours associated with foraging. Females appear to maximise feeding rates before entering the energetically demanding phase of late lactation. Little time was spent resting while outside the den. Longer nights and the full moon were associated with later emergence and earlier retirement times. Animals re-entered their tree-hollow dens during the night, representing 2% of activity in late spring, 18% in winter and 9% in autumn (10% overall). This behaviour may relate to predation risk and lactation demands. We reviewed the percentage of the time budget that petaurid gliders devoted to feeding and found no clear relationship with body size.

Time-budget and feeding behaviour of the squirrel glider (Petaurus norfolcensis) in remnant linear habitat

2007 ◽  
Vol 34 (4) ◽  
pp. 288 ◽  
Author(s):  
Greg J. Holland ◽  
Andrew F. Bennett ◽  
Rodney van der Ree
Keyword(s):  
Feeding Behaviour ◽  
Time Budget ◽  
Observation Time ◽  
Food Items ◽  
Roadside Vegetation ◽  
Acacia Gum ◽  
Linear Habitat ◽  
Eastern Australia ◽  
Large Trees ◽  
Squirrel Glider

The squirrel glider (Petaurus norfolcensis) occurs in forests and woodlands in eastern Australia. In Victoria it is now largely restricted to small, fragmented areas and is considered endangered. In this study, the time-budget, feeding behaviour and related habitat use of the squirrel glider were investigated in a linear remnant of roadside vegetation near Euroa, Victoria. Timed observations of three males and three females, fitted with radio-collars, were made in each of four seasons. Gliders were observed for a total of 53.2 h, during which they devoted 72% of time to foraging activities. Grooming accounted for 16% of observation time. Exudates associated with homopterous insects were the primary food items consumed throughout the year. Arthropods, nectar and pollen, and Acacia gum formed the remainder of the diet. The proportion of time devoted to harvesting these food items showed marked seasonal variation. The primary dependence on homopterous insect exudates in this study area contrasts with other investigations at sites of greater floristic diversity where nectar and pollen were the most important dietary resources. This highlights the need to obtain ecological information from the range of habitats occupied by a species. Large trees are a vital habitat component of remnant linear vegetation in this study area, providing gliders with critical foraging resources. Retention of such trees is essential for the longevity of glider populations.

The characteristics of squirrel glider (Petaurus norfolcensis) den trees in subtropical Australia

2008 ◽  
Vol 56 (1) ◽  
pp. 13 ◽  
Author(s):  
Georgia L. Beyer ◽  
Ross L. Goldingay ◽  
David J. Sharpe
Keyword(s):  
New South ◽  
Effective Management ◽  
Living Tree ◽  
Breast Height ◽  
North East ◽  
South Wales ◽  
Dead Trees ◽  
Squirrel Glider ◽  
Tree Hollow ◽  
Subtropical Australia

Effective management of tree-hollow-dependent wildlife requires a sound knowledge of the characteristics of the trees used for shelter or breeding. We used radio-tracking to identify the den trees of squirrel gliders (Petaurus norfolcensis) in south-east Queensland (Qld) and north-east New South Wales (NSW). Squirrel gliders used dead trees as well as 13 species of living tree for dens across the two locations. Dead trees accounted for a large percentage of dens (54% of 48 dens in Qld, and 50% of 18 dens in NSW) despite comprising only 3–10% of the forest (trees >20 cm diameter at breast height (dbh)) at each location. This preference is largely due to dead trees being more likely to contain hollows, accounting for 26–44% of available hollow-bearing trees. Mean den tree size (dbh) was 48.9 ± 2.4 cm in Qld and 62.8 ± 5.6 cm in NSW. Den entrance height averaged 6.8 ± 1.2 m in Qld and 11.9 ± 1.3 m in NSW. Fissures in the trunk and holes in branches were the most common of six hollow types used. At one location branch end hollows were ignored relative to their availability. Den entrances varied in size (2.5–12 cm wide) but most were ≤5 cm in diameter. Entrance size of hollows appears to be the hollow attribute of most importance to squirrel gliders. Monitoring of these den trees over several years revealed the collapse of three dead den trees at each location, which is equivalent to an annual loss of 3% of den trees. Further research is needed to determine whether this will lead to a future shortage of den trees.

Group size modulates time budget and foraging efficiency in captive Skylarks, Alauda arvensis

2011 ◽  
Vol 153 (2) ◽  
pp. 485-490 ◽  
Author(s):  
Thibaut Powolny ◽  
Cyril Eraud ◽  
Vincent Bretagnolle
Keyword(s):  
Group Size ◽  
Time Budget ◽  
Foraging Efficiency ◽  
Alauda Arvensis

scholarly journals Multiple-stage decisions in a marine central-place forager

2016 ◽  
Vol 3 (5) ◽  
pp. 160043 ◽  
Author(s):  
Ari S. Friedlaender ◽  
David W. Johnston ◽  
Reny B. Tyson ◽  
Amanda Kaltenberg ◽  
Jeremy A. Goldbogen ◽  
...  
Keyword(s):  
Foraging Behaviour ◽  
Central Place ◽  
Foraging Efficiency ◽  
Feeding Rates ◽  
Marine Animals ◽  
Air Breathing ◽  
Baleen Whales ◽  
Multi Stage ◽  
Central Place Forager ◽  
Prey Patches

Air-breathing marine animals face a complex set of physical challenges associated with diving that affect the decisions of how to optimize feeding. Baleen whales (Mysticeti) have evolved bulk-filter feeding mechanisms to efficiently feed on dense prey patches. Baleen whales are central place foragers where oxygen at the surface represents the central place and depth acts as the distance to prey. Although hypothesized that baleen whales will target the densest prey patches anywhere in the water column, how depth and density interact to influence foraging behaviour is poorly understood. We used multi-sensor archival tags and active acoustics to quantify Antarctic humpback whale foraging behaviour relative to prey. Our analyses reveal multi-stage foraging decisions driven by both krill depth and density. During daylight hours when whales did not feed, krill were found in deep high-density patches. As krill migrated vertically into larger and less dense patches near the surface, whales began to forage. During foraging bouts, we found that feeding rates (number of feeding lunges per hour) were greatest when prey was shallowest, and feeding rates decreased with increasing dive depth. This strategy is consistent with previous models of how air-breathing diving animals optimize foraging efficiency. Thus, humpback whales forage mainly when prey is more broadly distributed and shallower, presumably to minimize diving and searching costs and to increase feeding rates overall and thus foraging efficiency. Using direct measurements of feeding behaviour from animal-borne tags and prey availability from echosounders, our study demonstrates a multi-stage foraging process in a central place forager that we suggest acts to optimize overall efficiency by maximizing net energy gain over time. These data reveal a previously unrecognized level of complexity in predator–prey interactions and underscores the need to simultaneously measure prey distribution in marine central place forager studies.

scholarly journals Possums in the park: efficient foraging under the risk of predation or of competition?

2000 ◽  
Vol 48 (2) ◽  
pp. 155 ◽  
Author(s):  
Eve McDonald-Madden ◽  
Lian K. Akers ◽  
Deena J. Brenner ◽  
Sarah Howell ◽  
Blair W. Patullo ◽  
...  
Keyword(s):  
Urban Population ◽  
Foraging Behaviour ◽  
Field Experiments ◽  
Foraging Efficiency ◽  
Trichosurus Vulpecula ◽  
Initial Amount ◽  
Trade Off ◽  
Food Items ◽  
Risk Of Predation

Many eutherian mammals adjust their foraging behaviour according to the presence or threat of predators. Here, we examine experimentally whether an urban population of brushtail possums, Trichosurus vulpecula, similarly adjust their foraging behaviour. Our field experiments manipulated the quantity of food items in artificial feeders placed at different distances from trees. These experiments showed that the possums remained longer at feeders placed far from the trees, but their foraging behaviour did not change with the initial amount of food. The scanning behaviour of possums did not simply increase with distance from the trees, as predicted from studies of other vertebrates. Nevertheless, the number of physical conflicts between individuals increased as the amount of available food decreased. These data suggest that the changes in the foraging behaviour of the possums in this population do not reflect a simple trade-off between foraging efficiency and the risk of predation or competition.

Extra-Pair Copulations in the Red-Billed Gull: Females With High-Quality, Attentive Males Resist

Behaviour ◽  
1994 ◽  
Vol 128 (1-2) ◽  
pp. 41-64 ◽  
Author(s):  
J.A. Mills
Keyword(s):  
Mating System ◽  
Reproductive Investment ◽  
Pair Bond ◽  
Feeding Rates ◽  
High Quality ◽  
Fertile Period ◽  
Pair Bonds ◽  
Courtship Feeding ◽  
Term Pair ◽  
Strange Male

AbstractExtra-pair copulation (EPC) and within-pair copulation (WPC) behaviour of red-billed gulls (Larus novaehollandiae scopulinus) was observed in a breeding colony at Kaikoura Peninsula, New Zealand. Twenty-five females and 19 individually colour-marked males were monitored for six hours per day for twenty days from 20 September to 30 October 1973. Extra-pair copulation attempts were common, amounting to 21% of all copulation attempts, but less than 3% were successful during the fertile period of the female. Ten percent of EPCs were on males. Within-pair mountings were eight times more likely to end in cloacal contact than EPCs. Within-pair and EPC attempts occurred throughout the day, but the frequency of WPC attempts increased markedly towards evening, possibly as an adaptation to ensure last-male sperm precedence. Approximately 80% of females, but only 32% of males, were involved in EPC attempts. Mounting within and between pairs increased in frequency about 15 days prior to laying of the first cgg. Within-pair copulation attempts ceased abruptly after the first egg was laid, but EPC attempts on the female continued well into incubation and amounted to 11% of the total EPC attempts. Seventy-five percent of EPC attempts occurred in the fertile period of the recipient female. Approximately 75% of the EPC attempts by males occurred over a nine-day period; six days prior to and two days after its mate had laid the first egg. No EPC attempts were recorded for males more than seven days after its mate commenced laying. The female had control as to whether the copulation attempt would be successful. In WPC attempts the female ended the mount on 72% of the occasions, whereas all EPC attempts were ended by the female. Approximately 91% of within-pair mountings followed some form of courtship feeding display, and in the remaining 9% the male mounted without courtship preliminaries. In contrast, 97% of extra-pair mountings occurred in the absence of courtship displays. On the two instances where preliminaries occurred, mounting followed courtship feeding solicitation by the female towards the strange male. Potentially high quality females which were being well provisioned in courtship feeding by their mates were at greater risk from EPCs because they were able to spend more time at the nest site than less well provisioned females. Females which were well fed during courtship feeding resisted all EPC attempts and retained their partner the next breeding season. Poorly courtship fed females divorced the next season. One such female solicited an EPC four days prior to the laying of her first egg. There was no evidence to suggest that males performing EPCs were at risk from being cuckolded and the male partners of females experiencing high numbers of EPCs did not respond to the risk by having more WPCs or having more genital contacts per hour. It is considered that EPCs were not a major feature of the mating system for the majority of red-billed gulls. The advantages of EPCs were greater for females than for males and the results support the genetic quality hypothesis. Theoretically if males wanted to maximise their fitness they should attempt EPC's on females nesting earlier than themselves, but this only happened on 17% of the EPC attempts. The high number of WPCs, the increase in frequency of copulations in the evening and high courtship feeding rates are measures that help to ensure paternity of the true mate. It is hypothesized that in species like the red-billed gull which have long-term pair-bonds and invest considerable time and energy in courtship feeding and parental care during incubation and chick rearing it would be more advantageous to strengthen the pair-bond than to philander to increase production. In a mating system such as this, philandering would jeopardize the current reproductive investment and future reproduction because those which change partners are less productive than those which retain their partners and for those which divorce the probability of breeding the next season is lower than for those which retain pair-bonds (MILLS, unpub. data). More successful breeding occurs if the pair-bond has been established for more than one year (MILLS, unpub. data). Thus, in this mating system the ''attentive prosper''.

scholarly journals Diet and Activity Budget in Colobus angolensis ruwenzorii at Nabugabo, Uganda: Are They Energy Maximizers?

2020 ◽  
pp. 1-20
Author(s):  
T. Jean M. Arseneau-Robar ◽  
Amtul H. Changasi ◽  
Evan Turner ◽  
Julie A. Teichroeb
Keyword(s):  
Food Availability ◽  
Activity Budget ◽  
Foraging Strategies ◽  
High Quality ◽  
Black And White ◽  
Food Items ◽  
Leaf Consumption ◽  
Young Leaves ◽  
Quality Diet ◽  
Colobus Angolensis

<b><i>Introduction:</i></b> Colobine monkeys are specialized folivores that use foregut fermentation to digest leaves. The slow process of fermentation forces them to spend a lot of time resting and to minimize their energy expenditure to subsist on a lower-quality diet. <b><i>Methods:</i></b> We recorded the diet and activity budget of <i>Colobus angolensis ruwenzorii</i>, which form a three-tiered multi-level society, at Lake Nabugabo, Uganda, over 12 months using scan sampling on adults and subadults, to determine whether they utilize the energy minimization strategy typical of colobines. <b><i>Results:</i></b> We found that the annual diet was primarily comprised of high-quality food resources (young leaves 65% and fruit 31%), and fruits were the only plant part the monkeys<i></i>selected when available. Both the fruits and young leaves of some species were preferred food items in some months, and mature leaf consumption correlated negatively with preferred food availability. Mature leaves appear to be a fallback food for this population but are rarely relied upon (3%). The <i>C. a. ruwenzorii</i>at Nabugabo spent less time resting (40%) and more time moving (25%) than is typical for other species of black-and-white colobus. <b><i>Discussion/Conclusion:</i></b> The high-quality diet of this population appears to allow them to utilize an energy maximization strategy. Their reliance on food items that tend to be clumped in space and time likely explains the frequent fission-fusion behaviour that we observe between core units. Our findings demonstrate that the foraging strategies of colobines may be more flexible than was previously thought and illustrate how food availability and distribution can impact primate social organization.

scholarly journals The impact of turbidity on foraging and risk taking in the invasive Nile tilapia (Oreochromis niloticus) and a threatened native cichlid (Oreochromis amphimelas)

2020 ◽  
Author(s):  
Jonathan D B Wing ◽  
Toby S Champneys ◽  
Christos C Ioannou
Keyword(s):  
Invasive Species ◽  
Risk Perception ◽  
Risk Taking ◽  
Oreochromis Niloticus ◽  
Native Species ◽  
Nile Tilapia ◽  
Foraging Efficiency ◽  
Turbid Water ◽  
Water Turbidity ◽  
Food Items

AbstractAnthropogenic activity can increase water turbidity, changing fish behaviour by reducing visibility. The spread of invasive species is also facilitated by human activity, further increasing the pressure on native species. In two experiments we measured the foraging efficiency, risk perception and inter-individual consistency of risk-taking (personality variation in boldness) of an invasive species, the Nile tilapia (Oreochromis niloticus), and a threatened tilapia, the Manyara tilapia (Oreochromis amphimelas), in clear and turbid water. In experiment one, O. niloticus was faster to initiate feeding, encountered more food items, and consumed more than O. amphimelas. The latency to start foraging by O. niloticus decreased in turbid water. Turbidity did not affect the latency to start foraging in O. amphimelas but the number of food items they encountered was highest at the intermediate turbidity. There was however no significant effect of turbidity in either species on the total food consumed. In contrast to this foraging context, in experiment two with a refuge and no food available, risk taking behaviour was similar in both species and they both responded with similarly reduced risk taking in turbid water. Evidence of personality variation was weak, being observed only in O. amphimelas when first leaving the shelter in turbid water. Overall, species differences were greater in the foraging context but turbidity was more important in the risk-taking context. O. amphimelas is more sensitive to turbidity during foraging, and O. niloticus is likely to have a competitive advantage in foraging situations, especially in degraded turbid habitats.Significance StatementUnder human-induced environmental change, native species are often exposed to multiple stressors. Here we tested the responses of two cichlid fish to increasing turbidity. The Nile tilapia (Oreochromis niloticus), which is invasive throughout the tropics, and the Manyara tilapia (Oreochromis amphimelas), a threatened species, indigenous to Tanzania. We found that turbidity was beneficial to the foraging of O. niloticus, which in both clear and turbid water consumed and encountered more food than O. amphimelas. In contrast, without food present, both species displayed similar responses of increased risk perception in turbid water with little evidence of personality variation between individuals in either species. Our results suggest that invasive species tolerant of degraded habitats may outcompete less well adapted native species for food.

scholarly journals TIME BUDGET PRESSURE DAN KARAKTERISTIK PERSONAL AUDITORTERHADAP PERILAKU PREMATURE SIGN-OFF AUDIT PROCEDURES

2018 ◽  
Vol 16 (2) ◽  
pp. 18-38
Author(s):  
Sekar Akrom Faradiza ◽  
Januar Chritianto
Keyword(s):  
Locus Of Control ◽  
Turnover Intention ◽  
Audit Quality ◽  
Time Budget ◽  
Self Esteem ◽  
Rate Performance ◽  
Friedman Test ◽  
High Quality ◽  
Time Budget Pressure ◽  
Pressure Factor

To produce a high quality audit report, an auditor must carry out several audit procedures.Premature sign-off audit procedures is one of the behaviors that can reduce audit quality becauseignores and stops audit procedures that must be carried out in accordance with the audit program.The aims of this research is to examine the effect of time budget pressure and personal auditorcharacteristics on premature sign-off audit procedures. The characteristics considered consist ofexternal locus of control, auditor's self rate performance, turnover intention and self esteem. Inadditions this research also examines the sequence of procedures that are often stopped orabandoned by the auditor. This study used questionnaires to obtained data form 140 auditors inYogyakarta, Semarang and Surakarta. Based on the Friedman test, this research found that theprocedure for understanding client business often ignored by auditors. Based on the logisticregression test, this research found that the time budget pressure factor affects the behavior ofpremature sign-off audit procedures.  

scholarly journals Interactive effects of shifting body size and feeding adaptation drive interaction strengths of protist predators under warming

2017 ◽  
Author(s):  
K. E. Fussmann ◽  
B. Rosenbaum ◽  
U. Brose ◽  
B.C. Rall
Keyword(s):  
Body Size ◽  
Functional Response ◽  
Interactive Effects ◽  
Experimental Temperature ◽  
Foraging Efficiency ◽  
Positive Energy ◽  
Feeding Rates ◽  
Mixed Response ◽  
Different Temperatures ◽  
The Impact

AbstractGlobal change is heating up ecosystems fuelling biodiversity loss and species extinctions. High-trophic-level predators are especially prone to extinction due to an energetic mismatch between increasing feeding rates and metabolism with warming. Different adaptation mechanisms such as decreasing body size to reduce energy requirements (morphological response) as well as direct effects of adaptation to feeding parameters (physiological response) have been proposed to overcome this problem. Here, we use protist-bacteria microcosm experiments to show how those adaptations may have the potential to buffer the impact of warming on predator-prey interactions. After adapting the ciliate predator Tetrahymena pyriformis to three different temperatures (15°C, 20°C and 25°C) for approximately 20 generations we conducted functional response experiments on bacterial prey along an experimental temperature gradient (15°C, 20°C and 25°C). We found an increase of maximum feeding rates and half-saturation densities with rising experimental temperatures. Adaptation temperature had on average slightly negative effects on maximum feeding rates, but maximum feeding rates increased more strongly with rising experimental temperature in warm adapted predators than in cold adapted predators. There was no effect of adaptation temperature on half-saturation densities characterising foraging efficiency. Besides the mixed response in functional response parameters, predators also adapted by decreasing body size. As smaller predators need less energy to fulfil their energetic demands, maximum feeding rates relative to the energetic demands increased slightly with increased adaptation temperature. Accordingly, predators adapted to 25°C showed the highest feeding rates at 25°C experimental temperature, while predators adapted to 15°C showed the highest maximum feeding rate at 15°C. Therefore, adaptation to different temperatures potentially avoids an energetic mismatch with warming. Especially a shift in body size with warming additionally to an adaptation of physiological parameters potentially helps to maintain a positive energy balance and prevent predator extinction with rising temperatures.

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