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.

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.

scholarly journals Plumage brightness, vigilance, escape potential, and predation risk in male and female Eurasian Siskins (Spinus spinus)

The Auk ◽  
2014 ◽  
Vol 131 (1) ◽  
pp. 61-72 ◽  
Author(s):  
Jordi Pascual ◽  
Juan Carlos Senar ◽  
Jordi Domènech
Keyword(s):  
Predation Risk ◽  
Male And Female

Wolf predation in a multiple-ungulate system in northern British Columbia

1998 ◽  
Vol 76 (8) ◽  
pp. 1551-1569 ◽  
Author(s):  
A T Bergerud ◽  
J P Elliott
Keyword(s):  
British Columbia ◽  
Canis Lupus ◽  
Birth Rate ◽  
Rangifer Tarandus ◽  
Adult Mortality ◽  
Recruitment Rate ◽  
Wolf Predation ◽  
Rate Of Increase ◽  
Ovis Dalli ◽  
Hunting Statistics

Caribou (Rangifer tarandus), elk (Cervus canadensis), moose (Alces alces), and Stone's sheep (Ovis dalli stonei) were either decreasing or stable in numbers in two areas in northeastern British Columbia in 1981-1982, prior to reductions in wolf (Canis lupus) numbers. Following the reduction of wolf numbers, recruitment improved 2-5 times for all four species, and all populations increased, based on either hunting statistics, census results, and (or) recruitments greater than 24 offspring at 9 months of age per 100 females. Recruitment of offspring at 9 months of age, when regressed against wolf numbers, declined with decelerating slopes for all four species. This inverse functional response is hypothesized to result from the preparturient spacing of females to reduce predation risk, and in this regard moose seem the least secure and sheep the most effectively spaced. For the four species, mean recruitment at 9 months of age that balanced adult mortality and provided a finite rate of increase of 1.00 was 24.16 ± 0.91 offspring/100 females (n = 11, coefficient of variation = 12.5%). The predicted recruitment rate for all four species in the absence of wolves was 53-57 offspring/100 females. But the birth rate of moose was much higher than those of the other species, indicating greater loss to other factors of which bear predation may be the greatest. Following wolf reductions of 60-86% of entire travelling packs, the wolves quickly recolonized the removal zones, with rates of increase ranging from 1.5 to 5.6.

Kill rate by wolves on moose in the Yukon

2000 ◽  
Vol 78 (1) ◽  
pp. 49-59 ◽  
Author(s):  
R D Hayes ◽  
A M Baer ◽  
U Wotschikowsky ◽  
A S Harestad
Keyword(s):  
Canis Lupus ◽  
Snow Depth ◽  
Prey Density ◽  
Large Scale ◽  
Rangifer Tarandus ◽  
Prey Selection ◽  
Ecological Factors ◽  
Predation Rate ◽  
Wolf Predation ◽  
Kill Rate

We studied the kill rate by wolves (Canis lupus) after a large-scale wolf removal when populations of wolves, moose (Alces alces), and woodland caribou (Rangifer tarandus caribou) were all increasing. We followed a total of 21 wolf packs for 4 winters, measuring prey selection, kill rates, and ecological factors that could influence killing behavior. Wolf predation was found to be mainly additive on both moose and caribou populations. Kill rates by individual wolves were inversely related to pack size and unrelated to prey density or snow depth. Scavenging by ravens decreased the amount of prey biomass available for wolves to consume, especially for wolves in smaller packs. The kill rate by wolves on moose calves was not related to the number of calves available each winter. Wolves did not show a strong switching response away from moose as the ratio of caribou to moose increased in winter. The predation rate by wolves on moose was best modeled by the number and size of packs wolves were organized into each winter.

Distribution and abundance of Hemolivia mauritanica (Apicomplexa: Haemogregarinidae) and its vector Hyalomma aegyptium in tortoises of Iran

Biologia ◽  
2015 ◽  
Vol 70 (2) ◽  
Author(s):  
Hossein Javanbakht ◽  
Pavel Široký ◽  
Peter Mikulíček ◽  
Mozafar Sharifi
Keyword(s):  
Distribution Pattern ◽  
Age Groups ◽  
Climatic Conditions ◽  
Blood Parasite ◽  
Iranian Plateau ◽  
Male And Female ◽  
Testudo Graeca ◽  
Vector Tick ◽  
Significant Difference ◽  
Males And Females

AbstractDistribution pattern, prevalence and intensity of parasitaemia of heteroxenous apicomplexan blood parasite Hemolivia mauritanica and its vector tick Hyalomma aegyptium have been studied in 264 tortoises (212 Testudo graeca and 52 T. horsfieldii) throughout the Iranian territory. In T. graeca the highest prevalence and intensity of parasitaemia for H. mauritanica were recorded in the temperate mid and northern parts of the Iranian plateau, while the lowest values were found in the arid central part of Iran. No Hemolivia-positive samples were found in T. horsfieldii. Hyalomma aegyptium ticks were diagnosed in both tortoise species. The highest prevalence and intensity of infestation with H. aegyptium were recorded in western part of Iran, where climatic conditions are not so arid compared to central and eastern parts. No significant differences were found in intensity of parasitaemia of H. mauritanica between males and females. Similarly, no differences in intensity of parasitaemia were detected between different age groups (adults; more than 10 years, young; 5-10 years and juveniles; less that 5 years). Prevalence of H. mauritanica and H. aegyptium in adults was higher than in young and in juveniles. While intensity of infestation with H. aegyptium was significantly higher in adult tortoises compare to juveniles, no significant difference were found between intensity of H. aegyptium infestation in male and female tortoises.

scholarly journals Elk (Cervus elaphus) Seasonal Habitat Selection in a Heterogeneous Forest Structure

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Jesse N. Popp ◽  
David N. C. McGeachy ◽  
Josef Hamr
Keyword(s):  
Habitat Selection ◽  
Cervus Elaphus ◽  
Forest Structure ◽  
Hardwood Forests ◽  
Climatic Conditions ◽  
White Birch ◽  
Balsam Poplar ◽  
Adult Females ◽  
Selection Of ◽  
Future Management

Seasonal habitat selection by the reintroduced Burwash elk population, approximately 30 km south of Sudbury, Ontario, has been analysed in order to assist in the development of future management. Twenty-five adult females were radio-collared and tracked 1–3 times a week for 3 years. The most prominent patterns included selection of intolerant hardwood forests (trembling aspen, white birch, and balsam poplar) during all seasons, while Great Lakes-St. Lawrence pines (white and red pine dominated stands) were used less than expected based on availability for all seasons. The selection patterns are likely associated with seasonal climatic conditions and forage preferences. Because the selection behaviours displayed here varied greatly from other elk habitat studies, it is suggested that managers consider the importance of population-specific habitat studies before developing related strategies.

scholarly journals Actividad reproductiva y dieta de Hemidactylus frenatus (Sauria: Gekkonidae) en el norte de Colombia

2017 ◽  
Vol 57 (36) ◽  
pp. 459
Author(s):  
Jorge A. Díaz-Pérez ◽  
Alcides C. Sampedro-Marín ◽  
Martha P. Ramírez-Pinilla
Keyword(s):  
Diet Composition ◽  
Sampling Period ◽  
Reproductive Activity ◽  
Climatic Conditions ◽  
Relative Importance ◽  
Adult Males ◽  
Adult Females ◽  
Ecological Aspects ◽  
Environmental Availability ◽  
Hemidactylus Frenatus

Despite its success as an invasive species, little is known about the ecological aspects of the gekkonid lizard Hemidactylus frenatus in Colombia. In the present study the size at maturity, sexual dimorphism, reproductive activity, and diet composition of a population of this species in an urban locality of Northern Colombia were determined. We conducted eleven samplings from September 2011 to August 2012 in buildings of the municipality of Sincelejo. A total of 264 specimens H. frenatus were captured, 112 were adult females, 133 adult males and 19 juveniles. Males reach sexual maturity at a smaller size (snout-vent length) than females (males: 35.7 mm; females: 42.7 mm), also they are larger and have proportionally larger heads and mouths than females. Males were reproductive throughout the year; although testicular volume varied significantly between samples, this variation was not associated with body size and precipitation in the study area. Reproductive adult females were found during all the sampling period. Females have an invariable clutch size of two eggs and we found no differences in the diameter and weight of eggs in each oviduct. The diet of H. frenatus is varied, with Diptera, Hemiptera and Formicidae being the prey types with the greatest relative importance values. Individuals of both sexes consume a similar volume and number of prey. Thus, the studied population of H. frenatus has continuous reproductive activity and a generalist-opportunistic feeding behavior. The climatic conditions of the study area, environmental availability of prey and intrinsic features of this species appear to be responsible for their abundance and colonizing success in this and other localities.

scholarly journals Wolves, Canis lupus, Carry and Cache the Collars of Radio-collared White-tailed Deer, Odocoileus virginianus, they Killed

2011 ◽  
Vol 125 (1) ◽  
pp. 67 ◽  
Author(s):  
Michael E. Nelson ◽  
L. David Mech
Keyword(s):  
Odocoileus Virginianus ◽  
Canis Lupus

Wolves (Canis lupus) in northeastern Minnesota cached six radio-collars (four in winter, two in spring-summer) of 202 radio-collared White-tailed Deer (Odocoileus virginianus) they killed or consumed from 1975 to 2010. A Wolf bedded on top of one collar cached in snow. We found one collar each at a Wolf den and Wolf rendezvous site, 2.5 km and 0.5 km respectively, from each deer's previous locations.

scholarly journals Wolf, Canis lupus, Visits to White-tailed Deer, Odocoileus virginianus, Summer Ranges: Optimal Foraging?

2009 ◽  
Vol 123 (4) ◽  
pp. 299 ◽  
Author(s):  
Dominic J. Demma ◽  
L. David Mech
Keyword(s):  
Odocoileus Virginianus ◽  
Canis Lupus ◽  
Optimal Foraging ◽  
Major Part ◽  
Optimal Foraging Theory ◽  
Foraging Theory ◽  
Individual Female ◽  
Gps Collars

We tested whether Wolf (Canis lupus) visits to individual female White-tailed Deer (Odocoileus virginianus) summer ranges during 2003 and 2004 in northeastern Minnesota were in accord with optimal-foraging theory. Using GPS collars with 10- to 30-minute location attempts on four Wolves and five female deer, plus eleven VHF-collared female deer in the Wolves' territory, provided new insights into the frequency of Wolf visits to summer ranges of female deer. Wolves made a mean 0.055 visits/day to summer ranges of deer three years and older, significantly more than their 0.032 mean visits/day to ranges of two-year-old deer, which generally produce fewer fawns, and most Wolf visits to ranges of older deer were much longer than those to ranges of younger deer. Because fawns comprise the major part of the Wolf's summer diet, this Wolf behavior accords with optimal-foraging theory.

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