scholarly journals Why lemmings have indoor plumbing in summer

1996 ◽  
Vol 74 (10) ◽  
pp. 1947-1949 ◽  
Author(s):  
Rudy Boonstra ◽  
Charles J. Krebs ◽  
Alice Kenney
Keyword(s):  
Predation Risk ◽  
Ultraviolet Light ◽  
Canadian Arctic ◽  
Falco Tinnunculus ◽  
Vegetation Growth ◽  
Hunting Activity ◽  
Microtine Rodents ◽  
Dicrostonyx Groenlandicus ◽  
High Predation ◽  
Buteo Lagopus

The faeces and urine of microtine rodents are visible in ultraviolet light, and diurnal raptors, such as European kestrels (Falco tinnunculus) and rough-legged buzzards (Buteo lagopus), have the ability to see in ultraviolet light. It has been reported that in Fennoscandia, these raptors use this ability to concentrate their hunting activity in spring on areas where microtines are abundant. We hypothesized that in arctic tundra areas in summer, intense avian predation pressure and short vegetation should select for microtine behaviour that would minimize their exposure to these raptors. We dug up 62 collared lemming (Dicrostonyx groenlandicus) burrows in the Canadian Arctic and all had underground latrines. Latrines are not hidden underground in winter, when lemmings live under the snow, build nests above ground, and defecate above ground, nor does this occur in microtine species living in temperate areas, where summer vegetation growth is greater. Thus, high predation risk may influence not only where prey forage but also where they defecate.

High predation risk for a small mammal: the eastern pygmy-possum (Cercartetus nanus)

2013 ◽  
Vol 35 (2) ◽  
pp. 149 ◽  
Author(s):  
Bradley Law ◽  
Mark Chidel ◽  
Alf Britton
Keyword(s):  
Predation Risk ◽  
Small Mammal ◽  
High Predation ◽  
Cercartetus Nanus

We report high rates of predation within a population of eastern pygmy-possum (Cercartetus nanus) near Sydney, observed during a study of the impacts of logging on the species. Predation by reptiles was observed on six of 61 radio-tracked pygmy-possums, while two were suspected of being taken by raptors. We further investigated predation by sooty owls (Tyto tenebricosa) by identifying remains in pellets. Pygmy-possums comprised 15% of the 126 dietary items identified. Predation occurred at both logged and unlogged sites in our study. We suggest that documented high rates of predation in our study could make the species vulnerable to altered predation regimes, such as influxes of feral predators, and highlight the need for a better understanding of any influence of logging on predator activity.

Differences in behavior help to explain lemming coexistence

2019 ◽  
Vol 100 (4) ◽  
pp. 1211-1220 ◽  
Author(s):  
Douglas W Morris ◽  
Angélique Dupuch ◽  
MaryJane Moses ◽  
Kaylee Busniuk ◽  
Helen Otterman
Keyword(s):  
Open Field ◽  
Exploratory Behavior ◽  
Behavioral Response ◽  
Habitat Preferences ◽  
Canadian Arctic ◽  
Field Tests ◽  
Repeated Testing ◽  
Dicrostonyx Groenlandicus ◽  
Components Analysis ◽  
Innate Behaviors

Abstract Collared (Dicrostonyx groenlandicus) and brown (Lemmus trimucronatus) lemmings coexist in tundra habitats across much of the middle and lower Canadian arctic. Their coexistence, and response to predation risk, appears mediated by behavior. We analyzed field-collected videos of open-field tests to assess potential differences in innate behaviors between the two species. Collared lemmings were less active and exhibited less exploratory behavior than did brown lemmings, which were more active under cover than in the open. Similar behaviors scaling along axes of activity and curiosity were revealed by principal components analysis. Each axis defined different aspects of brown lemming personality, but repeated testing of the same individuals yielded a striking dependence of their behavioral response on open-field treatments. Even so, the differences between species in behavior correlate well with their habitat preferences that resolve competition and govern their coexistence.

Impact of high predation risk on genome-wide hippocampal gene expression in snowshoe hares

Oecologia ◽  
2014 ◽  
Vol 176 (3) ◽  
pp. 613-624 ◽  
Author(s):  
Sophia G. Lavergne ◽  
Patrick O. McGowan ◽  
Charles J. Krebs ◽  
Rudy Boonstra
Keyword(s):  
Gene Expression ◽  
Predation Risk ◽  
Snowshoe Hares ◽  
Genome Wide ◽  
High Predation

Do scent marks increase predation risk of microtine rodents?

Oikos ◽  
2001 ◽  
Vol 95 (2) ◽  
pp. 275-281 ◽  
Author(s):  
Minna Koivula ◽  
Erkki Korpimäki
Keyword(s):  
Predation Risk ◽  
Scent Marks ◽  
Microtine Rodents

Interrelationships within a raptor guild in the central Canadian Arctic

1988 ◽  
Vol 66 (10) ◽  
pp. 2275-2282 ◽  
Author(s):  
K. G. Poole ◽  
R. G. Bromley
Keyword(s):  
Body Size ◽  
Reproductive Success ◽  
Breeding Season ◽  
Prey Species ◽  
Canadian Arctic ◽  
Geographic Range ◽  
Time Space ◽  
Peregrine Falcons ◽  
Golden Eagles ◽  
Buteo Lagopus

The interrelationships of an arctic raptor guild comprising golden eagles (Aquila chrysaetos), gyrfalcons (Falco rusticolus), peregrine falcons (Falco peregrinus), rough-legged hawks (Buteo lagopus), and common ravens (Corvus corax) (a functional raptor) were studied from 1983 to 1986. Partitioning of time, space, and food generally related to body size; small-bodied species (peregrines and rough-legged hawks) nested later, had shorter reproductive periods, used smaller cliffs with less overhang, and took smaller prey than large-bodied species. The raven, a passerine, was often the exception. The onset of laying for each raptor was closely related to arrival or emergence of major prey species. Gyrfalcons and ravens selected well-protected sites, while other species selected sites with southerly aspects but little overhang protection. Overlap in prey use was high between eagles and gyrfalcons early in the breeding season. The spacing of all species except the rough-legged hawk tended to be regular, apparently as a result of intraspecific rather than interspecific factors. However, all species tended to nest far from occupied eagle sites. Reproductive success was not affected by distance to nearest intra- or inter-specific neighbor, except among gyrfalcons whose reproductive success was significantly lower when conspecifics nested within 5 km than when they nested farther away. Golden eagles, a species on the edge of its geographic range, had the lowest reproductive success of all species.

Some like it cool? Intermorph comparison of preferred body temperature in a colour-dimorphic snake

2009 ◽  
Vol 59 (1) ◽  
pp. 31-39 ◽  
Author(s):  
Koji Tanaka
Keyword(s):  
Body Temperature ◽  
Environmental Factors ◽  
Laboratory Experiment ◽  
Predation Risk ◽  
Field Studies ◽  
Behavioural Thermoregulation ◽  
Model Species ◽  
High Predation ◽  
Preferred Body Temperature ◽  
Recent Laboratory

AbstractOrganismal characteristics of ectotherms are profoundly affected by body temperature (Tb). Despite constraints imposed by environmental factors, they can adjust Tb by several means. However, if thermoregulatory ability is limited by their own property such as coloration and this constraint affects individual's fitness, selection may promote coevolution of coloration and thermal aspects. I investigated this topic using a colour-dimorphic (melanistic/striped) snake Elaphe quadrivirgata as a model species. Recent laboratory experiment revealed slower body warming in striped individuals than in melanistic individuals. Under this circumstance, one way that striped individuals can manage their slower body warming is to prefer low Tb. Contrary to this prediction, there was no intermorph difference in preferred Tb. Coupled with the results of field studies, I suggest that striped individuals manage their slower body warming by behavioural thermoregulation and that constraints (e.g., high predation risk due to conspicuousness under thermally superior habitats) imposed on melanistic individuals lessen their thermal advantages. The effect of melanism on thermal aspects may not be so advantageous for melanistic animals than generally thought.

Habitat as a source of intrapopulational variation of ornament size in Galápagos lava lizards (Microlophus albemarlensis complex)

2008 ◽  
Vol 29 (2) ◽  
pp. 278-283 ◽  
Author(s):  
Mark Jordan ◽  
Howard Snell ◽  
Jennifer Hollis ◽  
Paul Stone
Keyword(s):  
Predation Risk ◽  
Body Mass ◽  
Predator Avoidance ◽  
Habitat Structure ◽  
Predation Pressure ◽  
Residual Body ◽  
Galápagos Islands ◽  
Vegetative Cover ◽  
High Predation ◽  
Intrapopulational Variation

Abstract Gradients in habitat structure are expected to influence the outcome of selection on traits that contribute to communicative display. Galápagos lava lizards (Microlophus albemarlensis complex) on Isla Plaza Sur in the Galápagos Islands occur across a gradient of vegetative cover. Previous work in this population has shown that traits associated with predator avoidance are magnified in habitats with low vegetative cover. This pattern suggests that predation pressure differs by habitat and thus, may act to select against the elaboration of ornamentation. We measured the size of the chin patch, an ornament known to be used in intraspecific signaling, to test this hypothesis. The area of the chin patch was dependent on both snout-vent length and residual body mass. In contrast to expectation, males had larger chin patches in the sparsely vegetated habitat suggested to have high predation risk. This result raises questions about the presumed survival cost of ornament elaboration.

Differential effects of predation risk and competition over vigilance variables and feeding success in Eurasian siskins (Carduelis spinus)

Behaviour ◽  
2013 ◽  
Vol 150 (14) ◽  
pp. 1665-1687 ◽  
Author(s):  
Jordi Pascual ◽  
Juan Carlos Senar
Keyword(s):  
Food Intake ◽  
Predation Risk ◽  
Foraging Behaviour ◽  
Interference Competition ◽  
Ecological Factors ◽  
Intake Rate ◽  
Similar Length ◽  
Feeding Success ◽  
High Predation ◽  
Food Intake Rate

Many investigations have studied the effects of predation risk and competition over vigilance and feeding success, but they have proven to be difficult to discriminate. Moreover, none of the studies that have avoided the confusion has considered all the vigilance variables, food intake rate and time spent in the foraging patch. In this study, we designed an experiment with Eurasian siskinsCarduelis spinusforaging on three bird table feeders: one with low predation risk and competition, one with low predation risk and high competition and one with high predation risk and intermediate competition. Birds responded to increasing interference competition by increasing mean scan durations (probably due to the birds having to be vigilant for both other flock members and predators) and maintaining the length of mean inter-scan durations, while they responded to increasing predation risk by reducing mean inter-scan durations (probably in order to detect the predator sooner) while maintaining similar length of mean scan durations. Birds were often ejected from the feeder or departed because of disturbances, so time spent on feeders was reduced both because of competition and predation risk. Pecking rates were affected by competition but not by predation risk. Our results clearly show that birds vigilance strategy while foraging might be very different when they are mainly concerned with scanning for predators or when they primarily monitor competing flock companions. In addition, they stress the importance of recording all the vigilance and feeding variables when studying the effect of ecological factors over the foraging behaviour of birds.

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