scholarly journals Mobility of moose-comparing the effects of wolf predation risk, reproductive status, and seasonality

2016 ◽  
Vol 6 (24) ◽  
pp. 8870-8880 ◽  
Author(s):  
Camilla Wikenros ◽  
Gyöngyvér Balogh ◽  
Håkan Sand ◽  
Kerry L. Nicholson ◽  
Johan Månsson
Keyword(s):  
Predation Risk ◽  
Reproductive Status ◽  
Wolf Predation

Timing of the evening emergence of Hilgendorf’s tube-nosed bat (Murina hilgendorfi) in relation to roost type and season

2020 ◽  
pp. 1-11
Author(s):  
Hayato Takada
Keyword(s):  
Predation Risk ◽  
Vegetation Cover ◽  
Growth Stage ◽  
Outer Wall ◽  
First Record ◽  
Foraging Strategy ◽  
Late Spring ◽  
Reproductive Status ◽  
Central Japan ◽  
Behavioral Aspect

Abstract Like for many species, the timing of evening emergence of bats is an important behavioral aspect that affects their fitness and has been studied in various bat species. However, little is known about emergence timing of solitary bats that frequently switch day roosts, because they are difficult to observe. In this study, I examined the emergence timing of Hilgendorf’s tube-nosed bats (Murina hilgendorfi), which are solitary and frequently switch roosts, in relation to roost type and season over six years in Hayakawa, central Japan. The results show that the bats emerged after dusk when the light was weak. Later emergence may be related to the habits of this species, such as their solitary lifestyle, slow flight speed, and gleaning foraging strategy, which may enhance predation risk. Individuals roosting in dead foliage and on the outer wall of a building situated in closed forests emerged significantly earlier than those roosting in an old mine and tunnel located in open environments, suggesting that vegetation cover and/or lower predictability of roost location provide security for bats. Bats emerged progressively earlier from late spring (preparturition) to early autumn (late lactation or post-lactation), suggesting that the reproductive status of females or the growth stage of pups may influence emergence timing. To my knowledge, this study provides the first record of the emergence timing of Hilgendorf’s tube-nosed bat, and suggests that predation risk may impact the bats’ emergence behavior.

Wolf predation risk associated with white-tailed deer movements

1991 ◽  
Vol 69 (10) ◽  
pp. 2696-2699 ◽  
Author(s):  
Michael E. Nelson ◽  
L. David Mech
Keyword(s):  
Predation Risk ◽  
Odocoileus Virginianus ◽  
Canis Lupus ◽  
Climatic Conditions ◽  
Male And Female ◽  
Wolf Predation ◽  
Adult Females ◽  
Disproportionate Number ◽  
Short Time ◽  
Antipredator Strategy

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.

scholarly journals Extrinsic and intrinsic factors influencing the emergence and return of Asian particolored bats Vespertilio sinensis

2021 ◽  
Author(s):  
Lei Feng ◽  
Hexuan Qin ◽  
Jingjing Li ◽  
Xin Li ◽  
Jiang Feng ◽  
...  
Keyword(s):  
Light Intensity ◽  
Predation Risk ◽  
Environmental Changes ◽  
Return Time ◽  
Reproductive Status ◽  
Lactation Period ◽  
Emergence Time ◽  
Extrinsic Factors ◽  
Activity Rhythms ◽  
Return Times

The circadian rhythm is an adaptive biological process, allows organisms to anticipate daily environmental changes and implement appropriate strategies. Circadian rhythms play a crucial role in the health and survival of organisms. However, little is known concerning how intrinsic and extrinsic factors affect animal daily rhythms in the field, especially in nocturnal animals. Here, we investigated the emergence and return times of Vesperilio sinensis, and also integrated environmental conditions (temperature, humidity and light intensity) and biotic factors (reproductive status and predation risk) to determine causes of variation in the activity rhythms of the bats. We found that variation in the first emergence time, the mid-emergence time, and the final return time were distinct. The results demonstrated that the emergence and return times of bats were affected by light intensity, reproductive status, and predation risk in a relatively complex pattern. Light intensity had the greatest contribution to activity rhythms. Moreover, we first investigated the effects of actual predators on the activity rhythms of bats; the results showed that the mid-emergence time of bats was earlier as predators were hunting, but the final return time was later when predators were present. This challenges the traditional view that high predation risk leads to later emergence and earlier return. Finally, our results also highlighted the importance of higher energy demands during the lactation period in bats to variation in activity rhythms. These results improve our understanding of the patterns and causes of variation in activity rhythms in bats and other nocturnal animals.

scholarly journals Predation risk and optimal foraging trade-off in the demography and spacing of the George River Herd, 1958 to 1993

Rangifer ◽  
2003 ◽  
Vol 23 (5) ◽  
pp. 169 ◽  
Author(s):  
Arthur T. Bergerud ◽  
Stuart N. Luttich
Keyword(s):  
Predation Risk ◽  
Optimal Foraging ◽  
Late Summer ◽  
Energy Budgets ◽  
Trade Off ◽  
Wolf Predation ◽  
The North ◽  
Increased Risk ◽  
Energy Maximization ◽  
George River

The behavior options of feeding animals lie on a continuum between energy maximization and minimization of predation risk. We studied the distribution, mobility, and energy budgets of the George River herd, Ungava from 1974 to 1993. We arranged the annual cycle into 6 phases where we argue that the importance between the priorities of optimal foraging and predation risk change between periods. At calving, risk is more important than foraging for females but males take more risk to optimally forage. During the mosquito season, insect avoidance takes priority over risk and for¬aging. Optimal foraging takes precedent over risk in the late summer and fall and it is at this time that the herd expanded its range relative to numbers and forage abundance. In the winter (December to mid-March) animals sought restricted localized ranges with low snow cover to reduce predation risk. The spring migration of females may have increased risk during the interval the females were moving back to the tundra to give birth to their neonates on the low risk calv¬ing ground. In May, females sought early greens near treeline, which may have increased risk in order to provide maximum nutrition to their fetuses in the last weeks of pregnancy. The ancestors of the George River Herd during the Pleistocene, 18 000 yr. BP may have reduced predation risk by spacing-out in the Appalachian Mountains, removed from the major specie of the megafauna in the lowlands. With global warming, it is argued the major problem for caribou will be increased wolf predation rather than changing forage and nutritional regimes. It is essential that First Nation residents of the North maintain their option to manage wolf numbers if excessive predation in the future adversely affects the migratory herds of the Northwest Territories and Ungava.

scholarly journals Escape behavior in gravid and non-gravid females of Gonatodes albogularis (Squamata: Sphaerodactylidae)

2018 ◽  
Vol 17 (1) ◽  
pp. 73 ◽  
Author(s):  
Moisés E. Domínguez-López ◽  
Federico Pablo Kacoliris ◽  
María Verónica Simoy
Keyword(s):  
Predation Risk ◽  
Escape Behavior ◽  
Function Analysis ◽  
Theoretical Models ◽  
Reproductive Status ◽  
Risk Of Predation ◽  
Behavioral Compensation ◽  
Adaptive Processes ◽  
Free Search ◽  
Gravid Females

Escape behavior in gravid and non-gravid females of Gonatodes albogularis (Squamata: Sphaerodactylidae). Theoretical models of predator-prey relationships describe tradeoffs between energetic and other costs of escape, effectiveness of escape behavior, and predation risk. These models predict that an animal will fee when the expected ftness cost due to risk of predation becomes equal to the the cost of the escape or post-encounter ftness is maximized, depending on the model. In this framework, several individual and ecological variables have been shown to affect escape patterns, but the effect of reproductive status has been studied in few species. We assess differences in escape behavior between gravid and non-gravid females of Gonatodes albogularis. Lizards were surveyed by applying a free search method along independent transects. For each lizard, we determined reproductive status as gravid or non-gravid and recorded several variables related to escape behavior. We made a discriminant function analysis to see whether the state of individuals affect escape behavior. Our results show that the escape variables distance fed, the fnal distance and the distance to refuge differ between gravid and non-gravid females. These fndings support predictions based on risk and cost, but do not support models of fight initiation distance. Such differences could be related to a physiological process known as behavioral compensation, through which some individuals (gravid females in our case) modify their behavior to offset predation risk. Further studies are needed to see if behavioral compensation can be explained in terms of adaptive processes in G. albogularis.

scholarly journals Wolf predation risk and moose movement in eastern Finland

2020 ◽  
Vol 2020 (4) ◽  
Author(s):  
Jyrki Pusenius ◽  
Tuomas Kukko ◽  
Markus Melin ◽  
Sauli Laaksonen ◽  
Ilpo Kojola
Keyword(s):  
Predation Risk ◽  
Wolf Predation ◽  
Eastern Finland

scholarly journals Evolving perspectives on caribou population dynamics, have we got it right yet?

Rangifer ◽  
1996 ◽  
Vol 16 (4) ◽  
pp. 95 ◽  
Author(s):  
A.T. Bergerud
Keyword(s):  
North America ◽  
Predation Risk ◽  
Open Water ◽  
Tree Cover ◽  
The Arctic ◽  
Tree Line ◽  
Population Limitation ◽  
Wolf Predation ◽  
Annual Range ◽  
George River

The roles of food, weather and predation are compared between sedentary and migratory caribou herds. Sedentary herds disperse (space out) at calving time while the cows of migratory herds move in masse (space away) to calving grounds to reduce predation risk. The sedentary ecotype calves on ranges near open water if tree cover is present or in rugged topography in the absence of tree cover. The migratory ecotype aggregates on calving grounds located on alpine mountain plateaus or on the tundra north of the Arctic tree line. The two herds with the greatest densities in North America, the sedentary Slate Islands Herd and the migratory George River Herd both had changes in abundance that followed summer food problems. The hypothesis that winter lichen supplies determine abundance and set the carrying capacity is rejected. Lichens are not a necessary food for caribou. A review of the mortality of young calves documented in the past 30 years provides no support for the hypothesis that hypothermia is a common mortality problem. Young calves documented can be born inviable at birth if their dams are severely malnourished. The migratory caribou in North America reached peak numbers in the 1980s after wolf populations were heavily harvested in the 1970s. The sedentary ecotype is frequently regulated by wolf predation that affects both recruitment (R) and the mortality of adults (M). The balance between R/M schedules commonly occurs when R (calves) represents, about 15% of the herd and when numbers (prorated to the area of the dispersed annual range) approximate 0.06 caribou/km2. Population limitation of migratory herds by predation has occurred in the NWT and in several herds in Alaska but only when wolf densities were > 6.5/1000 km2. Wolf predation halted the growth of the George River Herd in 1980 but then wolves contracted rabies and the herd again increased and degraded spring/summer ranges. The reduced summer phytomass resulted in lower birth rates and increased the vulnerability of calves and possibly adults to wolf predation. Stabilizing mechanisms for migratory herds include movements between herds above tree line and range contractions/expansions with resultant changes in demography. It is hypothesized that the most important ecological variable in all seasonal distributions of caribou is predation risk rather than to maximize forage supplies.

scholarly journals A survey of the effects of wolf predation risk on pregnancy rates and calf recruitment in elk

2011 ◽  
Vol 21 (8) ◽  
pp. 2847-2853 ◽  
Author(s):  
Scott Creel ◽  
David A. Christianson ◽  
John A. Winnie
Keyword(s):  
Predation Risk ◽  
Pregnancy Rates ◽  
Wolf Predation

Effects of elk group size on predation by wolves

2002 ◽  
Vol 80 (5) ◽  
pp. 800-809 ◽  
Author(s):  
Mark Hebblewhite ◽  
Daniel H Pletscher
Keyword(s):  
Predation Risk ◽  
Group Size ◽  
Cervus Elaphus ◽  
Canis Lupus ◽  
National Park ◽  
Risk Model ◽  
Wolf Predation ◽  
Banff National Park ◽  
Density Relationship ◽  
Large Groups

Wolf-prey research has focused on single-prey systems in North America dominated by moose (Alces alces) or white-tailed deer (Odocoileus virginianus). Elk (Cervus elaphus) are social ungulates and the main prey item of wolves (Canis lupus) in Banff National Park (BNP), Alberta. Grouping behaviour may affect the functional response of predators by changing how predators encounter and kill prey. We studied wolf predation on elk in BNP during the winters of 1997–1998 and 1998–1999 and tested how elk group size affected the availability of and encounter rates with elk groups and attack success of wolves. Wolves encountered larger elk groups than expected based on availability, and killed more elk from large groups than expected based on numbers of encounters. Elk group size increased with elk density in BNP. Increased rates of encounter with and success of attacking large elk groups, and the positive group size – density relationship may be a mechanism for density-dependent predation. We developed a predation-risk model to test the prediction that grouping will benefit individual elk, given this predation regime. Elk appeared to adopt two different strategies to minimize predation risk: living in small herds that were rarely encountered by wolves or living in large herds that reduced their predation risk through dilution.

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