Food versus risk: foraging decision in young Tiger snakes, Notechis scutatus

2007 ◽  
Vol 28 (2) ◽  
pp. 304-308 ◽  
Author(s):  
Don Bradshaw ◽  
Xavier Bonnet ◽  
Fabien Aubret
Keyword(s):  
Predation Risk ◽  
Foraging Behaviour ◽  
High Food ◽  
Food Acquisition ◽  
Predation Threat ◽  
Trade Off ◽  
Foraging Decisions ◽  
Versus Risk ◽  
Foraging Decision

AbstractForaging behaviour is influenced by an animal's level of hunger, and may reflect a trade-off between optimizing food acquisition and avoiding predation. Young tiger snakes were raised either on a high or low food diet and exposed to a predation threat while foraging. Under these circumstances, lower condition snakes (low food diet) were prone to take additional feeding/foraging risks: food was accepted at a much higher rate compared with the higher condition animals (high food diet) that were less inclined to risk feeding under a predation threat. This study provides the first direct example of predation risk-associated foraging decisions in snakes.

scholarly journals Individual willingness to leave a safe refuge and the trade-off between food and safety: a test with social fish

2019 ◽  
Vol 286 (1907) ◽  
pp. 20190826 ◽  
Author(s):  
Jesse Balaban-Feld ◽  
William A. Mitchell ◽  
Burt P. Kotler ◽  
Sundararaj Vijayan ◽  
Lotan T. Tov Elem ◽  
...  
Keyword(s):  
Predation Risk ◽  
Foraging Behaviour ◽  
Foraging Success ◽  
Group Foraging ◽  
Refuge Use ◽  
Trade Off ◽  
Individual Fish ◽  
Risk Of Predation ◽  
Group Members ◽  
The Individual

Refuges offer prey animals protection from predation, but increased time spent hiding can reduce foraging opportunities. Within social groups, individuals vary in their refuge use and willingness to forage in the presence of a predator. Here, we examine the relative foraging benefits and mortality costs associated with individual refuge use and foraging behaviour within groups of goldfish ( Carassius auratus ) under predation risk from an avian predator (little egret— Egretta garzetta ). We assessed individual order of emergence from the refuge and participation over 15 group foraging outings, and assigned each fish a daily outing index score. The individual fish that emerged from the refuge earlier than the other group members and that participated in more outings received high outing index scores and consumed more food compared with fish that tended to emerge in posterior positions and participate in fewer outings. However, individual fish that attained high outing index scores suffered a higher risk of predation. Furthermore, the amount of time the egret spent at the pool affected group foraging behaviour: as predation risk increased, groups of fish consumed significantly less food. Our results exemplify the trade-off between foraging success and safety from predation that prey species regularly experience.

Risk sensitive foraging: an experimental study of a solitary marsupial.

2005 ◽  
Vol 27 (2) ◽  
pp. 231 ◽  
Author(s):  
LN Evans ◽  
MA Elgar ◽  
KA Handasyde
Keyword(s):  
Experimental Study ◽  
Early Detection ◽  
Predation Risk ◽  
Trade Off ◽  
Risk Sensitive ◽  
Risk Of Predation ◽  
Foraging Decisions ◽  
Foraging Site ◽  
Risk Sensitive Foraging

DETECTION and avoidance of predators are the principle strategies employed by prey to evade attack; by scanning their environment, prey individuals can reduce the likelihood of a predator approaching to within striking distance (Elgar 1989; Lima and Dill 1990). However, vigilance is often incompatible with foraging behaviours, and thus animals may be forced to trade-off the risk of predation against acquiring food. Consequently, the quality of a particular resource patch and its associated predation risk may influence the foraging decisions of animals (Werner et al. 1983; Newman and Caraco 1987; Heithaus and Dill 2002). Cover is an important feature of a foraging site because it can provide a hiding place to escape potential predators (Lazarus and Symonds 1992). Thus, animals may prefer foraging sites that are close to cover, or adjust their level of vigilance at different distances from cover in order to compensate for changes in the chance of early detection and escape (Elgar 1989; Lima and Dill 1990; Lima et al. 1985; Kramer and Bonenfant 1997).

scholarly journals Glucocorticoids, state-dependent reproductive investment and success in the face of danger in a long-lived bird

2020 ◽  
Author(s):  
Kristina Noreikienė ◽  
Kim Jaatinen ◽  
Benjamin B. Steele ◽  
Markus Öst
Keyword(s):  
Predation Risk ◽  
Telomere Length ◽  
Clutch Size ◽  
Body Condition ◽  
Nest Predation ◽  
Hatching Success ◽  
Reproductive Investment ◽  
Trade Off ◽  
Relative Telomere Length ◽  
Future Reproduction

AbstractGlucocorticoid hormones may mediate trade-offs between current and future reproduction. However, understanding their role is complicated by predation risk, which simultaneously affects the value of the current reproductive investment and elevates glucocorticoid levels. Here, we shed light on these issues in long-lived female Eiders (Somateria mollissima) by investigating how current reproductive investment (clutch size) and hatching success relate to faecal glucocorticoid metabolite [fGCM] level and residual reproductive value (minimum years of breeding experience, body condition, relative telomere length) under spatially variable predation risk. Our results showed a positive relationship between colony-specific predation risk and mean colony-specific fGCM levels. Clutch size and female fGCM were negatively correlated only under high nest predation and in females in good body condition, previously shown to have a longer life expectancy. We also found that younger females with longer telomeres had smaller clutches. The drop in hatching success with increasing fGCM levels was least pronounced under high nest predation risk, suggesting that elevated fGCM levels may allow females to ensure some reproductive success under such conditions. Hatching success was positively associated with female body condition, with relative telomere length, particularly in younger females, and with female minimum age, particularly under low predation risk, showing the utility of these metrics as indicators of individual quality. In line with a trade-off between current and future reproduction, our results show that high potential for future breeding prospects and increased predation risk shift the balance toward investment in future reproduction, with glucocorticoids playing a role in the resolution of this trade-off.

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

Predation risk and distance to cover affect foraging behaviour in Namib Desert gerbils

1993 ◽  
Vol 46 (6) ◽  
pp. 1243-1245 ◽  
Author(s):  
Jessica J. Hughes ◽  
David Ward
Keyword(s):  
Predation Risk ◽  
Foraging Behaviour ◽  
Namib Desert
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