Rareness as an Antipredator Strategy to Reduce Predation Risk for Moose and Caribou

The survival of 159 yearling and adult deer (Odocoileus virginianus) was monitored by telemetry during 282 spring and 219 fall individual migrations to winter deeryards in northeastern Minnesota. A disproportionate number of deer were killed by wolves (Canis lupus) during fall migration relative to the short time they spent migrating, but not during spring migration. Predation was also significantly greater for male and female yearlings and adult females outside deeryards during winter. Survival of 79 yearlings dispersing from natal ranges was high (1.00). It appears that changing climatic conditions combined with unfamiliar terrain and undetermined factors predispose migratory deer to wolf predation during fall. These findings support an earlier hypothesis that winter yarding is an antipredator strategy.

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Behavioral adjustments to prior predation experience and food deprivation of a common cyprinid fish species vary between singletons and a group

PeerJ ◽

10.7717/peerj.7236 ◽

2019 ◽

Vol 7 ◽

pp. e7236 ◽

Cited By ~ 2

Author(s):

Ya Wang ◽

Shi-Jian Fu ◽

Cheng Fu

Keyword(s):

Locomotor Activity ◽

Predation Risk ◽

Food Competition ◽

Control Fish ◽

Food Shortages ◽

The Difference ◽

Predator Risk ◽

And Control ◽

Antipredator Strategy ◽

Increased Activity

Fish often undergo predation stress and food shortages in nature, and living in groups may provide the ecological benefits of decreased predator risk but the costs of increased food competition. The main aim of the present study was to test whether the behavioral response of qingbo (Spinibarbus sinensis) to predators and/or starvation differed between a singleton and a group. We measured the locomotor activity and distance to a predator and/or food item of prior predator-experienced, starved, double-treated and control qingbo; the qingbo were tested both as singletons and in a group (five individuals). Fish from all groups showed increased activity when tested collectively compared to individually. The predator-experienced fish showed decreased locomotor activity to predators as an antipredator strategy when tested as singletons; however, increased locomotor activity occurred when tested in a group, which might be partially due to the decreased predator risk when living in a group and thus higher levels of boldness. As expected, starvation elicited increased activity indicating increased foraging willingness when tested in a group; however, the difference between starved and normal-fed fish was no longer significant when they were tested as singletons, possibly due to the increased predation risk and decreased food competition when living individually and higher behavioral variation among individual fish than among those in a shoal. Compared with the control fish, the double-treated fish showed no difference in activity when tested both individually and collectively (except a slower speed when tested in a group). The reason for the results from the singletons might be an offset of the effect of predator exposure and starvation. The reason for this difference in the group might be due to the impaired body condition indicated by a slower swimming speed as a consequence of severe stress. The present study demonstrated that behavioral adjustment was closely related to the size of the group, which might be due to differences in the predation risk and food competition.

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Friends because of foes: the interplay between space use and sociality in mediating predation risk

10.22541/au.161278648.82814812/v1 ◽

2021 ◽

Author(s):

Christina Prokopenko ◽

Edward Ellington ◽

Alec Robitaille ◽

Jaclyn Aubin ◽

Juliana Balluffi-Fry ◽

...

Keyword(s):

Spatial Variation ◽

Predation Risk ◽

Comprehensive Evaluation ◽

Movement Ecology ◽

Social Response ◽

Costs And Benefits ◽

Antipredator Response ◽

Movement Synchrony ◽

Antipredator Strategy ◽

Ambush Predators

From the perspective of prey, movement synchrony can represent either a potent anti-predator strategy or a dangerous liability. Prey must balance the costs and benefits of using conspecifics to mediate risk and the emergent patterns of risk-driven sociality depends on the spatial variation and trait composition of the system. Our literature review outlined the prevailing, but not universal, trend of animals using sociality as an antipredator strategy. Empirically, we then used movement synchrony as a measure of social antipredator response of two ungulates to spatial variation in predator and prey habitat domains. We demonstrated that these responses vary based on prey vulnerability and predator hunting modes. Prey favored asynchrony when calves were present and within habitat domains of ambush predators but not pursuit predators. By unifying community ecology concepts such as habitat domains with movement ecology we provided a comprehensive evaluation of factors mediating prey social response to predation risk.

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Elevated nest predation risk promotes offspring size variation in birds with prolonged parental care.

10.32942/osf.io/h2mpw ◽

2019 ◽

Author(s):

Gretchen F. Wagner ◽

Emeline Mourocq ◽

Michael Griesser

Keyword(s):

Predation Risk ◽

Reproductive Cycle ◽

Perceived Risk ◽

Nest Predation ◽

Bird Species ◽

Size Variation ◽

Egg Laying ◽

Offspring Size ◽

Natural Predation ◽

Risk Spreading

Predation of offspring is the main cause of reproductive failure in many species, and the mere fear of offspring predation shapes reproductive strategies. Yet, natural predation risk is ubiquitously variable and can be unpredictable. Consequently, the perceived prospect of predation early in a reproductive cycle may not reflect the actual risk to ensuing offspring. An increased variance in investment across offspring has been linked to breeding in unpredictable environments in several taxa, but has so far been overlooked as a maternal response to temporal variation in predation risk. Here, we experimentally increased the perceived risk of nest predation prior to egg-laying in seven bird species. Species with prolonged parent-offspring associations increased their intra-brood variation in egg, and subsequently offspring, size. High risk to offspring early in a reproductive cycle can favour a risk-spreading strategy particularly in species with the greatest opportunity to even out offspring quality after fledging.

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