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 Quadratic relationships between group size and foraging efficiency in a herbivorous primate

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Cyril C. Grueter ◽  
Andrew M. Robbins ◽  
Didier Abavandimwe ◽  
Veronica Vecellio ◽  
Felix Ndagijimana ◽  
...  
Keyword(s):  
Group Size ◽  
Foraging Efficiency

Seasonal Habitat Use by Nubian Ibex (Capra Nubiana) Evaluated with Behavioral Indicators

2011 ◽  
Vol 57 (3) ◽  
pp. 223-246 ◽  
Author(s):  
Solomon A. Tadesse ◽  
Burt P. Kotler
Keyword(s):  
Group Size ◽  
Age Structure ◽  
Time Allocation ◽  
Environmental Variables ◽  
Time Budget ◽  
Habitat Type ◽  
Time Budgets ◽  
Behavioral Models ◽  
Risk Of Predation ◽  
Focal Observation

Nubian ibex (Capra nubiana) prefer steep terrain in their landscape to reduce risks of predation and human nuisance disturbances. They also use vigilance and time allocation to manage risk of predation. We studied time budgets and habitat selection of Nubian ibex to: (1) identify the habitat variables to which Nubian ibex were behaviorally responsive; (2) investigate how time budget responses of Nubian ibex were related to season, slope condition, group size, and sex-age structure; and (3) develop behavioral-based models that account for the variations in the behaviors of Nubian ibex across the landscape and seasons.To quantify time budgets, we took regular field observations on focal individuals of Nubian ibex classified according to their habitat, group size, sex, and age. For each focal observation, we quantified environmental variables that were thought to influence the behavioral responses of ibex. Then, we developed behavioral models by correlating the proportion of behaviors measured in focal animal observations to the influential environmental variables. The behaviors of Nubian ibex significantly varied with sex and age structure, season, habitat type, and slope conditions. Adult females are more vigilant than adult male ibex, especially in the spring. This correlates with breeding and nursing activities. Based on the characteristics of the habitat, ibex behave to minimize risks of predation and human nuisance disturbances while maximizing their food intake.

Time budgets and synchrony of activities in muskoxen: the influence of sex, age, and season

1997 ◽  
Vol 75 (10) ◽  
pp. 1628-1635 ◽  
Author(s):  
Steeve D. Côté ◽  
James A. Schaefer ◽  
François Messier
Keyword(s):  
Group Size ◽  
Time Budget ◽  
High Arctic ◽  
Late Winter ◽  
Time Budgets ◽  
Adult Males ◽  
Ovibos Moschatus ◽  
Group Type ◽  
June July ◽  
Victoria Island

Synchrony of activities and time budgets of age–sex classes of muskoxen (Ovibos moschatus) was studied on Victoria Island in the Canadian High Arctic during late winter (April – late May), spring (late May – early June) and summer (mid-June – July). As revealed by the kappa (κ) coefficient of agreement, herd members exhibited significant synchrony in 79 of 82 groups. The degree of synchrony was not related to group size in mixed herds but decreased with group size in bachelor herds. Diversity in age–sex classes, group type (mixed versus bachelor), and season did not affect synchrony. However, synchrony was less among adult males than among other age–sex classes. Muskoxen were more synchronised at the start of activity bouts than at the end. As revealed by principal components analysis, calves tended to spend more time lying and standing and less time feeding than other age–sex classes. In addition, males in bachelor groups tended to feed more and rest less than males in mixed herds. Duration of active and lying bouts was not affected by age–sex class. Length of active bouts did not change with season, but lying bouts decreased in length significantly from late winter to spring and from spring to summer. We suggest that synchrony of activities maintains group cohesion but constrains the time budget of some group members, especially adult males.

Effects of habitat, group-size, sex-age class and seasonal variation on the behavioural responses of the mountain nyala (Tragelaphus buxtoni) in Munessa, Ethiopia

2013 ◽  
Vol 30 (1) ◽  
pp. 33-43 ◽  
Author(s):  
Solomon A. Tadesse ◽  
Burt P. Kotler
Keyword(s):  
Group Size ◽  
Time Budget ◽  
Activity Patterns ◽  
Habitat Type ◽  
Dry Season ◽  
Adult Males ◽  
Wet Season ◽  
Behavioural Responses ◽  
Age Class ◽  
Habitat Variables

Abstract:Activity patterns of animals are generally influenced by many factors. We hypothesized that the behavioural responses (i.e. activity time-budget allocated to vigilance, feeding and moving) of mountain nyala (Tragelaphus buxtoni) should vary with habitat type, season, group-size and sex-age class. We randomly established a total of 12 permanent walking transects with the aid of a GPS device across three major habitat types used by the mountain nyala (i.e. four transects in each habitat). Following each transect, we conducted focal-animal observations to quantify the time-budget allocated to vigilance, feeding and moving. A total of 119 and 116 focal-animals were assessed in the wet and dry season respectively. Moreover, along each transect, seven habitat variables were collected in systematically laid 109 circular plots each with a 5-m radius (i.e. 31, 41 and 37 plots in the cleared vegetation, plantation and natural forest respectively) in the wet and dry season. We developed behavioural models by correlating the time-budget (i.e. proportion of time vigilance, feeding and moving) of the focal-animals in accordance with habitat variables, group-size and sex-age class. In the wet season, mountain nyala devoted most of their time to vigilance, but they allocated the largest proportion of their time to moving in the dry season. Vigilance differed among the three habitats and was highest in the cleared vegetation during the dry season. Contrary to expectations, adult males were more vigilant than both adult females and sub-adults during the dry season. The behavioural models based on time-budget help to predict how the mountain nyala perceive their environment and trade-off between food acquisition and safety in the wet and dry season. The study also improves our understanding of the adaptive behavioural ecology of the endangered mountain nyala.

Consequences of Joint-Territoriality in a Mixed-Species Group of Tamarin Monkeys

Behaviour ◽  
1992 ◽  
Vol 123 (3-4) ◽  
pp. 220-246 ◽  
Author(s):  
Carlos A. Peres
Keyword(s):  
Time Budget ◽  
Species Group ◽  
Foraging Efficiency ◽  
Home Ranges ◽  
Foraging Success ◽  
Territorial Defence ◽  
Saguinus Fuscicollis ◽  
Small Fruit ◽  
Tamarin Monkeys ◽  
Time And Energy

AbstractGroups of saddle-back (Saguinus fuscicollis) as moustached tamarins (Saguinus mystax) in a western Amazonian forest jointly defended home ranges larger than 100 ha, which were held in common throughout the year. Resources were defended by direct exploitation in extensive areas shared with other groups, or through intensive and frequent intergroup interactions along territorial boundaries. These interactions were expressed primarily during intergroup encounters, and affected the use of space, movements, time budget, and foraging success of tamarins. During encounters, animals of both species spent more time in energetically costly activities, such as rapid travel and intergroup chases, and less time in energetically positive activities, such as feeding and foraging. In addition, foraging success per unit of foraging effort within overlapping areas of the range periphery was lower than in exclusive areas of the range centre, particularly for saddle-back tamarins. The time and energy allocated by moustached tamarins to boundary contests was considerably greater than that of saddle-backs, despite the fact that only the latter species increased its foraging efficiency by shifting from exclusive areas in the group's range to those shared by other groups. This is probably because of saddle-back's greater use of depletable food supplies, such as small fruit patches and small microhabitats containing embedded prey items. These benefits are likely to justify the substantial amount of time and energy invested in territorial defence for both saddle-backs and moustached tamarins, but appeared to be highly asymmetric between species.

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.

scholarly journals Up for grabs: prey herding by penguins facilitates shallow foraging by volant seabirds

2019 ◽  
Vol 6 (6) ◽  
pp. 190333 ◽  
Author(s):  
A. M. McInnes ◽  
P. A. Pistorius
Keyword(s):  
Group Size ◽  
Inverse Relationship ◽  
Vertical Displacement ◽  
Foraging Efficiency ◽  
Shallow Waters ◽  
Foraging Success ◽  
Seabird Species ◽  
Marine Communities ◽  
Prey Biomass ◽  
Strong Inverse Relationship

Visual and olfactory signals are commonly used by seabirds to locate prey in the horizontal domain, but foraging success depends on prey depth and the seabird's ability to access it. Facilitation by diving seabirds has long been hypothesized as a mechanism to elevate deep prey to regions more accessible to volant seabirds, but this has never been demonstrated empirically. Footage from animal-borne video loggers deployed on African penguins was analysed to establish if volant seabird encounters involved active cuing by seabirds on penguins to obtain prey and, during mutual prey encounters, if interactions were driven by the vertical displacement of prey by penguins. Independent of prey biomass estimates, we found a strong inverse relationship between penguin group size, a proxy for visibility, and the time elapsed from the start of penguins' dive bouts to their first encounter with other seabirds. Most mutual prey encounters (7 of 10) involved schooling prey elevated from depths greater than 33 m by penguins and only pursued by other seabird species once prey was herded into shallow waters. This is likely to enhance foraging efficiency in volant seabird species. As such, penguins may be integral to important processes that influence the structure and integrity of marine communities.

The Breeding Behaviour of the Pink-Footed Goose: Parental Care and Vigilant Behaviour During the Fledging Period

Behaviour ◽  
1978 ◽  
Vol 65 (1-2) ◽  
pp. 62-87 ◽  
Author(s):  
Lazarus John ◽  
Inglis I.R.
Keyword(s):  
Sex Differences ◽  
Parental Care ◽  
Group Size ◽  
Parental Investment ◽  
Brood Size ◽  
Time Budget ◽  
Feeding Time ◽  
Anser Brachyrhynchus ◽  
Term Pair ◽  
Pink Footed Goose

In this study we describe the pattern of parental investment in the pink-footed goose (Anser brachyrhynchus) during the fledging period in Iceland, concentrating particularly on the analysis of vigilant behaviour as one important element of parental care. We quantify parental investment, and its cost to the parent, by comparing the behaviour of parents with that of 'pairs' of adults without young (most of which are probably failed breeders). Each partner's strategy of investment is not expected to be purely selfish in this long-term pair-bonding species, and the sex differences in parental care are examined in this light. The time budgets of parents and pairs differed, parents walking more, grazing more and preening less. Parents also spent more time in the extreme head up posture and less in the head low and head on back postures than pairs but time devoted to the head up posture was the same for both. Brood size had no effect on the time budget. Time spent extreme head up declined over the study period in parents but not in pairs. Spacing patterns and behaviour varied independently in non-breeding birds but families sat closer to other geese when the vigilance level of the parents was low (i.e. in the head on back or head low postures) than when it was high (the head up or extreme head up postures). All agonistic encounters between parents and non-breeders were both initiated and won by the parents. Tied encounters occurred between birds of equivalent status in terms of brood size or non-breeding group size. The potential sources of parental care are summarized (Table 6) and, after considering the evidence for each, it is concluded that (apart from brooding) two types of parental investment are made by parents: (1) enhancement of offspring feeding efficiency by reducing competition through agonistic behaviour, and perhaps avoidance; and (2) protection from predators by (a) active defence, (b) seeking proximity with other geese when resting, and (c) visual scanning for predators (mainly by the male) using the extreme head up posture. Parents paid for this investment by devoting less time to preening and sleeping. The male's investment in predator vigilance was made at the cost of a reduced feeding time and to compensate for this he pecked at a faster rate than his mate. These sex differences are explicable in terms of earlier differences during incubation. The adoption of unrelated goslings was observed and the implications of the phenomenon are discussed. For individuals in non-breeding groups the time spent extreme head up declined as group size increased. The functional significance of this finding is discussed and it is concluded that in sitting groups extreme head up is probably used to scan for predators.

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