scholarly journals Vigilance and foraging behaviour of female caribou in relation to predation risk

Rangifer ◽  
1997 ◽  
Vol 17 (2) ◽  
pp. 55 ◽  
Author(s):  
Pernille S. Bøving ◽  
Eric Post
Keyword(s):  
Predation Risk ◽  
Group Size ◽  
Rangifer Tarandus ◽  
Foraging Behaviour ◽  
West Greenland ◽  
Vigilance Behaviour ◽  
Calving Season ◽  
Lying Down ◽  
Behavioural Adaptations

Behaviour of female caribou (Rangifer tarandus) was investigated during the calving season on ranges in Alaska and West Greenland with the purpose of determining whether investment in vigilance behaviour differed between areas with and without natural predators of caribou. Female caribou in Alaska foraged in larger groups, displayed a higher rate of vigilance during feeding, spent less time feeding and, when lying, more often adopted a vigilant posture (with head up) than did female caribou in West Greenland. Moreover, a predation-vulnerable posture of lying down flat was observed in West Greenland but not in Alaska. Within Alaska, females with calves spent more time searching the environment than did those without calves. Finally, the amount of time individuals spent searching declined more gradually with group size in Alaska than in West Greenland, suggesting that what caribou perceive as a predator-safe threshold differs in the two areas. These results indicate that caribou, like several other species of ungulates, show behavioural adaptations to the risk of prédation which are relaxed when this risk is reduced.

Invasion of the Forest By an African Savannah Monkey: Behavioural Adaptations

Behaviour ◽  
1980 ◽  
Vol 73 (3-4) ◽  
pp. 238-260 ◽  
Author(s):  
Michael Kavanagh
Keyword(s):  
Group Size ◽  
Related Species ◽  
Cercopithecus Aethiops ◽  
Alarm Calls ◽  
Agricultural Pests ◽  
South West ◽  
Vigilance Behaviour ◽  
Call Repertoire ◽  
Behavioural Adaptations ◽  
Male Pattern

AbstractTantalus monkeys, a race of the savannah species Cercopithecus aethiops, have invaded the cultivated forest of Bakossi in south-west Cameroon during the last seventy years and become important agricultural pests. The cultivated forest is a new habitat to which they are well adapted by virtue of their eclectic diet, their habit of foraging away from tall trees, their semi-terrestriality, their flexible group size and their cryptic nature. The indigenous related species of the rainforest are less able to exploit the changed habitat, probably because they are insufficiently terrestrial or cryptic and they typically forage among the trees that provide their refuge. As a result of their conflict with the farmers whose crops they raid, the forest tantalus monkeys contrast with conspecifics in the savannah by their less predictable ranging patterns, their quieter call repertoire, a striking and consistent male pattern of vigilance behaviour and their habit of hiding from dogs rather than giving the loud alarm calls that are invariably given where canids are not associated with man.

Effects of predation risk on foraging behaviour and group size: adaptations in a social cooperative species

2012 ◽  
Vol 84 (4) ◽  
pp. 823-834 ◽  
Author(s):  
Enrico Sorato ◽  
Philippa R. Gullett ◽  
Simon C. Griffith ◽  
Andrew F. Russell
Keyword(s):  
Predation Risk ◽  
Group Size ◽  
Foraging Behaviour

VIGILANCE IN BRONZE MANNIKIN GROUPS: THE CONTRIBUTIONS OF PREDATION RISK AND INTRA-GROUP COMPETITION

Behaviour ◽  
2000 ◽  
Vol 137 (5) ◽  
pp. 565-578 ◽  
Author(s):  
Nicola Coumi ◽  
Rob Slotow
Keyword(s):  
Predation Risk ◽  
Group Size ◽  
Foraging Behaviour ◽  
Random Numbers ◽  
Time Budgets ◽  
Group Competition ◽  
Measured Time ◽  
The Mean

AbstractWe describe foraging behaviour and time budgets of the gregarious bronze mannikin, Lonchura cucullata. In addition to being the first such study of a southern African granivore, this was the first study of a group-forager to differentiate between vigilance for other flock members (conspecifics) and vigilance for predators. We verified a perception of predation risk by placing five feeders at increasing distances from cover. The mean number of birds at a feeder decreased significantly with increasing distance from cover. We manipulated levels of aggression by restricting access to random numbers of feeding holes at various distances. The treatments succeeded in forcing birds to feed further from cover, and by inference, increased levels of aggression. We measured time budgets with focal samples on marked individuals. There was no influence of group size on time budgets. There was a non-significant (p < 0.06) trend for vigilance to increase with increasing distance from cover (predation risk). There was no pattern in the relative vigilance for predators as opposed to vigilance for other flock members (conspecifics), either with group size, distance from cover, or manipulated levels of aggression. Despite our inability to detect patterns of vigilance for other flock members, we emphasize the importance of studies to elucidate such a process.

scholarly journals Sleeping gulls monitor the vigilance behaviour of their neighbours

2008 ◽  
Vol 5 (1) ◽  
pp. 9-11 ◽  
Author(s):  
Guy Beauchamp
Keyword(s):  
Predation Risk ◽  
Group Size ◽  
Complex Flow ◽  
Vigilance Behaviour ◽  
Flow Of Information

Individuals in groups are often thought to scan their surroundings for threats independently of one another. Models, however, suggest that foragers should monitor the vigilance level of their neighbours to prevent cheating, and to gather information about incipient predation risk. Evidence for monitoring of vigilance is scant. Here, I examined changes in vigilance levels in sleeping gulls ( Larus sp.) surrounded by neighbours in various states of alertness. Controlling for group size and neighbour density, gulls interrupted sleep more often to scan their surroundings, and were therefore more vigilant, when their neighbours were alert rather than sleeping or preening. The results provide evidence for copying of vigilance within groups of birds, suggesting a complex flow of information about predation risk in groups.

Vigilance in human groups: a test of alternative hypotheses

Behaviour ◽  
2002 ◽  
Vol 139 (5) ◽  
pp. 695-711 ◽  
Author(s):  
◽  
◽  
◽  
Keyword(s):  
Predation Risk ◽  
Group Size ◽  
Inverse Relationship ◽  
Mate Guarding ◽  
Mate Searching ◽  
Clear Cut ◽  
Vigilance Behaviour ◽  
Alternative Hypotheses

AbstractHumans exhibit the same inverse relationship between group size and vigilance rates that has been classically described in animals. We collected data on natural human vigilance behaviour in two different contemporary environments (a large refectory-style cafeteria and open parks) to test between four alternative hypotheses for this relationship: predation risk, searching for friends, mate searching and mate guarding. The results demonstrate that, at least in contemporary city environments, humans monitor their surroundings largely for reasons motivated by mate searching. Data on whom subjects look at in a busy environment indicate that males are significantly more likely to attend differentially to female passers-by, but that females show a less clear-cut discrimination. We conclude that vigilance patterns are determined by locally salient functions.

Design of experimental food patches to measure foraging intensity for octopus: a case study with the giant Pacific octopus Enteroctopus dofleini

2020 ◽  
Author(s):  
Stephanie Chancellor ◽  
David Scheel ◽  
Joel S Brown
Keyword(s):  
Predation Risk ◽  
Foraging Behaviour ◽  
Habitat Preferences ◽  
High Tide ◽  
Intertidal Habitat ◽  
Camera System ◽  
Subtidal Habitat ◽  
Enteroctopus Dofleini ◽  
Nontarget Species

ABSTRACT In a study of the foraging behaviour of the giant Pacific octopus Enteroctopus dofleini, we designed two types of experimental food patches to measure habitat preferences and perceptions of predation risk. The first patch successfully measured giving-up densities (GUDs), confirmed by octopus prey presence and higher foraging at sites with historically greater octopus presence. However, nontarget foragers also foraged on these experimental food patches. Our second floating patch design successfully excluded nontarget species from subtidal patches, and from intertidal patches at high tide, but allowed for foraging by E. dofleini. The second design successfully measured GUDs and suggested that octopus preferred foraging in a subtidal habitat compared to an intertidal habitat. We ascribe the higher GUD in the intertidal habitat to its higher predation risk relative to the subtidal habitat. The second patch design seems well suited for E. dofleini and, in conjunction with a camera system, could be used to provide behavioural indicators of the octopus's abundance, perceptions of habitat quality and predation risk.

Modification of 0+ perch foraging behaviour by indirect cues of predation risk

2006 ◽  
Vol 15 (2) ◽  
pp. 118-124 ◽  
Author(s):  
J. Wanzenbock ◽  
V. N. Mikheev ◽  
A. F. Pasternak
Keyword(s):  
Predation Risk ◽  
Foraging Behaviour ◽  
Indirect Cues
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