Migratory fuelling in blackcaps ( Sylvia atricapilla ) under perceived risk of predation

1997 ◽  
Vol 41 (2) ◽  
pp. 75-80 ◽  
Author(s):  
Thord Fransson ◽  
Thomas P. Weber
Keyword(s):  
Perceived Risk ◽  
Sylvia Atricapilla ◽  
Risk Of Predation

scholarly journals Effects of a New Pedestrian Pathway in Grand Teton National Park on Breeding Sagebrush Songbirds

2008 ◽  
Vol 31 ◽  
pp. 3-7
Author(s):  
Anna Chalfoun
Keyword(s):  
Perceived Risk ◽  
Breeding Habitat ◽  
Energy Budgets ◽  
Human Presence ◽  
Wildlife Species ◽  
Fitness Consequences ◽  
Risk Of Predation ◽  
Natural Landscapes ◽  
Wildlife Populations ◽  
Induced Changes

Human-induced changes to natural landscapes have become ubiquitous, resulting in exposure of wildlife populations to novel stressors (Munns 2006). While it is clear that changes such as habitat loss can directly impact wildlife species, less clear is the extent to which human presence itself functions as a disturbance that influences wildlife behaviors with important fitness consequences. Animals clearly respond to perceived risk of predation by natural predators via, for example, fleeing, or altering foraging and/or breeding habitat selection (Marzluff 1988, Hakkarainen et al. 2001, Frid and Dill2002, Blumstein 2006, Borkowski et al. 2006, Fontaine and Martin 2006). Such responses can alter access to important resources, energy budgets, and therefore attributes such as body condition (Bechet et al. 2004) with potential impacts to survival and reproductive output. Of critical importance to the management of wildlife populations is therefore to determine 1) whether wildlife species perceive human presence as predation risk, 2) how individuals respond to such risk, and 3) how such responses influence fitness consequences and therefore population dynamics and community structure.

Female mouthbrooders adjust incubation duration to perceived risk of predation

2004 ◽  
Vol 68 (6) ◽  
pp. 1275-1281 ◽  
Author(s):  
Barbara Taborsky ◽  
Katharina Foerster
Keyword(s):  
Perceived Risk ◽  
Risk Of Predation ◽  
Incubation Duration

Effect of Turbidity on the Predator Avoidance Behaviour of Juvenile Chinook Salmon (Oncorhynchus tshawytscha)

1993 ◽  
Vol 50 (2) ◽  
pp. 241-246 ◽  
Author(s):  
Robert S. Gregory
Keyword(s):  
Chinook Salmon ◽  
Perceived Risk ◽  
Predator Avoidance ◽  
Oncorhynchus Tshawytscha ◽  
Avoidance Behaviour ◽  
Fish Predator ◽  
Juvenile Chinook Salmon ◽  
Risk Of Predation ◽  
Juvenile Chinook ◽  
Predator Risk

The effect of turbidity on the predator avoidance behaviour of juvenile chinook salmon (Oncorhynchus tshawytscha) was determined in controlled laboratory experiments. Bird and fish models were used to simulate predator risk. In the absence of risk, juvenile chinook were distributed randomly within an experimental arena in turbid conditions (≈23 NTU), but in clear conditions (<1 NTU) they associated with the bottom. When introduced to bird and fish predator models, the chinook altered their distribution and occupied deeper parts of the arena regardless of turbidity level. However, their responses in turbid conditions were less marked and of shorter duration. Turbidity apparently reduced the perceived risk of predation in juvenile chinook.

Monopolization of food by zebrafish (Danio rerio) increases in risky habitats

2002 ◽  
Vol 80 (12) ◽  
pp. 2164-2169 ◽  
Author(s):  
Ian M Hamilton ◽  
Lawrence M Dill
Keyword(s):  
Danio Rerio ◽  
Coefficient Of Variation ◽  
Perceived Risk ◽  
Open Habitat ◽  
Risk Of Predation ◽  
Resource Monopolization

Dominant zebrafish (Danio rerio) previously have been shown to reduce their monopolization of food when foraging in structurally complex habitats compared with open habitats. Complex habitats may be more difficult to defend but may also be safer. To decouple these effects, we compared aggression and monopolization of food in groups of zebrafish foraging in an open habitat and one with overhead cover, as well as in an open habitat and a complex (vegetated) habitat. Covered and open habitats should have been equally defendable. In our experiments, fish used covered habitats more than open ones, suggesting that the perceived risk of predation was lower in covered habitats. There was no difference in use of vegetated and open habitats, suggesting that these habitats, which should differ in defendability, did not differ in safety. We found that the degree of food monopolization (expressed in the coefficient of variation within groups) at risky feeders was significantly greater in open habitats than in covered, but not vegetated, habitats. We did not find a difference in aggression between habitats. These results indicate that resource monopolization in groups of zebrafish is greater in risky habitats and support the hypothesis that the lower monopolization of food in complex habitats could result from greater safety in those habitats rather than, or in addition to, the reduction in defendability.

Foraging Response to Risks of Predation and Competition in Artificial Pools

2010 ◽  
Vol 56 (1) ◽  
pp. 9-20 ◽  
Author(s):  
Gil Stav ◽  
Burt P. Kotler ◽  
Leon Blaustein
Keyword(s):  
Perceived Risk ◽  
Foraging Activity ◽  
Left Behind ◽  
Similar Tendency ◽  
Green Toad ◽  
Risk Of Predation ◽  
Giving Up Density ◽  
Culiseta Longiareolata ◽  
The Rich ◽  
Resource Patches

Although ecologists have learned much about the influence of competitors and perceived risk of predation on foraging in terrestrial systems by measuring giving-up density (GUD, the amount of food left behind in a resource patch following exploitation), GUDs have rarely been used in aquatic environments. Here we use foraging activity (proportion foraging) and GUDs to assess the effects that two periphyton consumers and potential competitors, green toad (Bufo viridis) tadpoles and mosquito (Culiseta longiareolata) larvae, have on each other. We also examine the effects of perceived risk of predation imposed by a dragonfly nymph (Anax imperator). To do so, we conducted an artificial pool experiment and developed a food patch appropriate for measuring GUDs for periphyton grazers. MoreCulisetaindividuals foraged in rich food patches than in poor patches.Bufoshowed a similar tendency. FewerBufoforaged in both patch types in the presence of cagedAnax. Culisetashowed a similar tendency. However, in the rich patches, onlyBuforeduced foraging activity when the caged predator was present. BothBufoandCulisetadepleted food patches through exploitation, resulting in lower GUDs. Both competitors together resulted in lower GUDs than did food depletion of each species alone. However, the presence of cagedAnaxhad little or no effects on GUDs. Overall, bothBufoandCulisetarespond to food and safety. They are able to direct foraging effort to richer patches and devote more time to those patches, and they respond to predation risk by choosing whether or not to exploit resource patches.

scholarly journals The strength of a female mate preference increases with predation risk

2008 ◽  
Vol 276 (1657) ◽  
pp. 775-780 ◽  
Author(s):  
Tae Won Kim ◽  
John H Christy ◽  
Stefan Dennenmoser ◽  
Jae C Choe
Keyword(s):  
Sexual Selection ◽  
Predation Risk ◽  
Perceived Risk ◽  
General Pattern ◽  
Visual Orientation ◽  
Relative Preference ◽  
Avian Predators ◽  
Risk Of Predation ◽  
Courtship Signals ◽  
Perceived Predation Risk

When females search for mates and their perceived risk of predation increases, they less often express preferences for males that use conspicuous courtship signals, relaxing sexual selection on production of these signals. Here, we report an apparent exception to this general pattern. Courting male fiddler crabs Uca beebei sometimes build pillars of mud at the openings to their burrows in which crabs mate. Females visit several males before they choose a mate by staying and breeding in their burrows, and they preferentially visit males with pillars. Previous studies suggested that this preference is based on a visual orientation behaviour that may reduce females' risk of predation while searching for a mate. We tested this idea by determining whether the female preference for males with pillars increases with perceived predation risk. We attracted avian predators to where crabs were courting and measured the rates that sexually receptive females visited courting males with and without mud pillars. Under elevated risk, females continued to search for mates and they showed a stronger relative preference for males with pillars. Thus, when predation risk is high, females may continue to express preferences that are under natural selection because they help females avoid predation, strengthening sexual selection for use of the preferred signal.

scholarly journals Perceived Risk of Predation Affects Reproductive Life-History Traits in Gambusia holbrooki, but Not in Heterandria formosa

PLoS ONE ◽  
2014 ◽  
Vol 9 (2) ◽  
pp. e88832 ◽  
Author(s):  
Shomen Mukherjee ◽  
Michael R. Heithaus ◽  
Joel C. Trexler ◽  
Jayanti Ray-Mukherjee ◽  
Jeremy Vaudo
Keyword(s):  
Life History ◽  
Perceived Risk ◽  
Life History Traits ◽  
Gambusia Holbrooki ◽  
Risk Of Predation ◽  
Reproductive Life ◽  
Heterandria Formosa ◽  
Reproductive Life History

Do long-tailed macaques avoid large heterospecific carcasses?

Behaviour ◽  
2021 ◽  
pp. 1-12
Author(s):  
Jeffrey V. Peterson ◽  
Agustín Fuentes
Keyword(s):  
Predation Risk ◽  
Nonhuman Primate ◽  
Perceived Risk ◽  
Macaca Fascicularis ◽  
Future Research ◽  
Tree Line ◽  
Risk Of Predation ◽  
Vigilance Behaviour ◽  
Pathogen Avoidance

Abstract This anecdotal observation details the response of long-tailed macaques (Macaca fascicularis) to a heterospecific carcass. The subgroup of macaques we were following abruptly changed their direction of travel upon reaching a tree line while displaying silent vigilance behaviour. We later discovered a dog carcass in the area and concluded their behaviour may have been in response to the smell of that carcass. The carcass was not visible from the response point at the tree line due to its distance from that point (approximately 30 meters) and the uneven and densely vegetated terrain between. The macaques were therefore most likely responding to scent cues from the carcass. We suggest the observed vigilance behaviour is excessive under a strictly pathogen-avoidance explanation and may be understood as a response to a cue of potential predation risk. We review alternative explanations and suggest future research on nonhuman primate heterospecific carcass avoidance is necessary to fully assess the potential relation to perceived risk of predation.

Does exposure to cues of fish predators fed different diets affect morphology and performance of Northern Leopard Frog (Lithobates pipiens) larvae?

2013 ◽  
Vol 91 (4) ◽  
pp. 203-211 ◽  
Author(s):  
Rayan El Balaa ◽  
Gabriel Blouin-Demers
Keyword(s):  
Life History ◽  
Phenotypic Plasticity ◽  
Perceived Risk ◽  
Leopard Frog ◽  
Predatory Fish ◽  
Lithobates Pipiens ◽  
Northern Leopard Frog ◽  
Risk Of Predation ◽  
Fish Predators ◽  
Plastic Changes

Phenotypic plasticity allows animals to change their morphological and life-history traits when exposed to predator cues, which modifies performance and can enhance survival but engender costs. Thus, the extent of plastic changes should vary in relation to the perceived risk of predation. We tested the hypothesis that plastic changes in morphology (and their effect on performance) and life history of developing Northern Leopard Frog (Lithobates pipiens (Schreber, 1782)) larvae vary when exposed to cues of fish predators fed different diets. During development, we exposed tadpoles to control cues, cues from brown bullhead (Ameiurus nebulosus (Lesueur, 1819)) fed trout pellets, or cues from A. nebulosus fed L. pipiens tadpoles. Tadpoles exposed to predatory fish cues had smaller bodies, deeper tail fins, slower growth and development rates, and better turning performance than tadpoles that were not exposed to predatory fish cues, but we found limited evidence that the predator’s diet had an effect on phenotypic plasticity. Predator diet affected tail morphology and activity, but the latter effect was only marginally significant. Lithobates pipiens tadpoles clearly respond to predatory fish cues, but it remains unclear whether their response is modulated by the predator’s diet.

Effects of Background Color and Predation Risk on Color Change in Fire Salamander Larvae

2009 ◽  
Vol 55 (4) ◽  
pp. 359-367 ◽  
Author(s):  
Ori Segev
Keyword(s):  
Predation Risk ◽  
Perceived Risk ◽  
Color Change ◽  
White Background ◽  
Color Matching ◽  
Background Color ◽  
Background Matching ◽  
Threat Sensitivity ◽  
Risk Of Predation ◽  
Fire Salamander

The threat-sensitivity hypothesis assumes individuals should demonstrate flexibility in response to perceived predation risk and vary the intensity of anti-predator responses in concert with perceived risk of predation. Substrate color matching is adaptive as it enables organisms to become less conspicuous to both their prey and predators. I hypothesized that newborn fire salamander (Salamandra infraimmaculata) larvae will respond fast through physiological color change to contrasting backgrounds, becoming lighter against a white background and darker against a black background. Additionally, in accordance with the threat-sensitivity hypothesis, I expected a background color x predator interaction—i.e., that predator presence will further enhance the focal larvae color-matching response. To explicitly test these hypotheses I conducted a replicated outdoor mesocosm experiment. I used a two-by-two factorial design: pools of black or white background color crossed with the presence or absence of a larger cannibalistic conspecific. Digital photos of the focal larvae's dorsal view revealed that larval brightness and chroma changed accordingly against the contrasting black and white backgrounds to increase background matching. Although not statistically significant, larvae tended to show a stronger color-change response towards enhanced background matching in the presence of the free predator. Larval survival was strongly reduced in the presence of the larger conspecific, with no apparent effect of background color. This study demonstrates that Salamandra larvae are capable of environmentally induced physiological color change and highlights the need for further investigation into the interplay between threat intensity, mechanisms of risk assessment, and physiological antipredator responses.

Sign in / Sign up

Export Citation Format

Share Document