scholarly journals Caribou calf deaths from intraspecific strife — a debatable diagnosis

Rangifer ◽  
1986 ◽  
Vol 6 (2) ◽  
pp. 203
Author(s):  
Frank L. Miller ◽  
Anne Gunn
Keyword(s):  
Canis Lupus ◽  
Aggressive Behaviour ◽  
Small Area ◽  
Rangifer Tarandus ◽  
Alternative Explanation ◽  
Physical Contact ◽  
Short Period ◽  
Newborn Calves ◽  
Calf Mortality ◽  
Rangifer Tarandus Groenlandicus

led to the deaths of several newborn barren-ground caribou (Rangifer tarandus groenlandicus) calves within a short period of time and on a small area. This event took place during calving in June 1958 on the calving ground of the Beverly caribou herd in the Northwest Territories. The lack of other examples of multiple deaths of newborn caribou calves from intraspecific strife and our findings on the same calving ground during a study of calf mortality in June 1981, 1982, and 1983 and a study of cow-calf behaviour in June 1981 and 1982 cause us to question the published explanation. As we rarely saw aggressive behaviour among cows and newborn calves that involved actual physical contact and none that resulted in injury or death and because we found instances of multiple killings of calves by wolves {Canis lupus) we suggest that a probable alternative explanation of the 1958 findings is surplus killing by wolves. Most importantly, only direct observation of an event allows separation of a death caused by injuries due to intraspecific strife from a death caused by accidental injuries.

scholarly journals What Happened to the Beverly Caribou Herd after 1994?

ARCTIC ◽  
2015 ◽  
Vol 68 (4) ◽  
pp. 407 ◽  
Author(s):  
Jan Adamczewski ◽  
Anne Gunn ◽  
Kim G. Poole ◽  
Alexander Hall ◽  
John Nishi ◽  
...  
Keyword(s):  
Rangifer Tarandus ◽  
Alternative Explanation ◽  
Herd Size ◽  
Barren Ground ◽  
Management Actions ◽  
The North ◽  
Large Size ◽  
Ground Survey ◽  
Newborn Calves ◽  
Rangifer Tarandus Groenlandicus

The Beverly herd was one of the first large migratory herds of barren-ground caribou (Rangifer tarandus groenlandicus) defined in northern Canada on the basis of annual return of breeding females to traditional calving grounds near Beverly Lake in Nunavut. In 1994, herd size was estimated at 276 000 ± 106 600 (SE) adult caribou, but monitoring was minimal from 1994 to 2007. The next calving ground survey in 2002 revealed that caribou densities had dropped by more than half since 1994; annual surveys following from 2007 to 2009 demonstrated an extreme decline in numbers of calving cows, and by 2011, no newborn calves were seen there. We examine two possible explanations for the declining use of the traditional Beverly calving grounds from 1994 until their abandonment by 2011. One explanation is that a true numerical decline in herd size occurred, driven in at least the later stages by low cow survival and poor calf productivity, which led the remaining Beverly cows to switch to the neighbouring Ahiak calving ground 250 km to the north in 2007 – 09 and join that herd. An alternative explanation is that the decline on the traditional Beverly calving grounds was largely due to a distributional shift to the north of the Beverly herd that may have begun in the mid-1990s. We suggest that the former explanation is the more likely and that the Beverly herd no longer exists as a distinct herd. We acknowledge that gaps in monitoring of Beverly and Ahiak caribou hamper definitive evaluation of the Beverly herd’s fate. The large size sometimes achieved by barren-ground caribou herds is not a guarantee of persistence; monitoring shortfalls may hamper management actions to address declines.

Limiting effects of snow on seasonal habitat use and diets of caribou (Rangifer tarandus groenlandicus) on Coats Island, Northwest Territories, Canada

1988 ◽  
Vol 66 (9) ◽  
pp. 1986-1996 ◽  
Author(s):  
J. Z. Adamczewski ◽  
C. C. Gates ◽  
B. M. Soutar ◽  
R. J. Hudson
Keyword(s):  
Northwest Territories ◽  
Rangifer Tarandus ◽  
Late Winter ◽  
Winter Conditions ◽  
Winter Food ◽  
Calf Mortality ◽  
Insular Population ◽  
Rangifer Tarandus Groenlandicus ◽  
Seasonal Habitat Use ◽  
Salix Spp

The insular population of barren-ground caribou (Rangifer tarandus groenlandicus) on Coats Island, Northwest Territories, is ultimately limited by winter food resources. This study was undertaken to assess forage biomass available during summer and to determine the effects of snow on forage availability in winter. Vegetation was low in density and diversity, but provided ample forage of high quality in summer for the 2000–2500 caribou existing on the island. Aboveground green biomass averaged only 50–60 g∙m−2 in mesic and wet meadows, the most productive habitats. Caribou fed almost exclusively in meadows throughout the snow-free period; willows (Salix spp.) constituted 80–90% of rumen contents in caribou collected during the summer. Lichens were scarce and were a major food only at the beginning and end of winter. During mid and late winter, hard-packed snow averaged 4000–9000 g∙cm−2 in hardness and 50–80 cm in depth on all low-lying vegetation. Under these conditions, caribou cratered only where snow was less than 10–20 cm deep; consequently feeding was limited to the slopes of wind-blown ridges and the tops of high-centre polygons. Forage available under these winter conditions was drastically reduced in quantity and quality compared with forage available in summer. During winter 1983 – 1984, snow accumulated rapidly and prolonged deep snow cover was associated with high calf mortality.

scholarly journals Energy-expending behaviour in frightened caribou when dispersed singly or in small bands

Rangifer ◽  
1997 ◽  
Vol 17 (1) ◽  
pp. 44
Author(s):  
Otto Blehr
Keyword(s):  
Canis Lupus ◽  
Rangifer Tarandus ◽  
Look Back ◽  
Save Energy ◽  
The One ◽  
Rangifer Tarandus Groenlandicus

The behaviour of single, and small bands of caribou (Rangifer tarandus groenlandicus) when confronted by humans was compared with the energy—saving behaviour zoologists have ascribed to caribou in encounters with non-hunting wolves (Canis lupus). When confronted by me, or upon getting my scent, caribou ran away on all occasions. Their flight was occasionally interrupted by short stops to look back in my direction, but would continue on all occasions until they were out of sight. This behaviour is inconsistent with the one ascribed to caribou by zoologists when the intruder is a wolf instead of a human. In their view, the caribou stop their flight soon after the wolf gives up the chase, and accordingly save energy owing to their ability to distinguish between hunting and non-hunting wolves. However, small bands of caribou, as well as single animals, have never been observed to behave in this manner. On the contrary, the behaviour of caribou in such encounters is known to follow the same pattern as in their encounters with humans. Energy—saving behaviour is, however, sometimes observed when caribou become inquisitive about something in their surroundings. They will then readily approach as well as try to get down-wind of the object. When the object does not induce fear, it may simply be ignored, or charged before the caribou calm down. The effect of this "confirming behaviour" is that energy which would otherwise have been spent in needless flights from non-predators is saved.

scholarly journals Predation of a Barren-ground Caribou, Rangifer tarandus groenlandicus, by a Single Gray Wolf, Canis lupus, in Northern Manitoba, Canada

2010 ◽  
Vol 124 (3) ◽  
pp. 270
Author(s):  
Brian W. Kiss ◽  
Scott K. Johnstone ◽  
Robert P. Berger
Keyword(s):  
Canis Lupus ◽  
Rangifer Tarandus ◽  
Open Water ◽  
Gray Wolf ◽  
Small Section ◽  
Barren Ground ◽  
Rangifer Tarandus Groenlandicus

A single Gray Wolf (Canis lupus) was observed successfully trapping and predating a Barren-ground Caribou (Rangifer tarandus groenlandicus) in a small section of open water.

Surplus killing as exemplified by wolf predation on newborn caribou

1985 ◽  
Vol 63 (2) ◽  
pp. 295-300 ◽  
Author(s):  
Frank L. Miller ◽  
Anne Gunn ◽  
Eric Broughton
Keyword(s):  
Northwest Territories ◽  
Canis Lupus ◽  
Rangifer Tarandus ◽  
The Other ◽  
Wolf Predation ◽  
Barren Ground ◽  
Rangifer Tarandus Groenlandicus

We searched for newborn calf carcasses of migratory barren-ground caribou (Rangifer tarandus groenlandicus) in June 1982 in the Northwest Territories. On 17 June, we found 34 calves killed by wolves (Canis lupus), clumped in a 3-km2 area. The calves had been killed apparently within minutes of each other and about 24 h before being found. Wolves had not fed on 17 of the carcasses and had only partially eaten the other 17. Ground observations illustrate the speed of and efficiency with which wolves can kill calves: a single wolf killed three calves on one occasion and three and possibly four calves on a second occasion at average kill rates of 1 calf/min, and 1 calf/8 min or 1 calf/6 min between the first and last deaths. We attributed the surplus killing of newborn caribou calves to their high densities and their vulnerability on the calving grounds. We recommend that a distinction be made between "surplus killing" and "excessive killing" by predators.

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.

scholarly journals Age-specific fecundity of the Beverly herd of barren-ground caribou

Rangifer ◽  
1990 ◽  
Vol 10 (3) ◽  
pp. 257 ◽  
Author(s):  
Donald C. Thomas ◽  
Samuel J. Barry
Keyword(s):  
Rangifer Tarandus ◽  
Barren Ground ◽  
Rangifer Tarandus Groenlandicus

The age-specific fecundity of the Beverly herd of barren-ground caribou (Rangifer tarandus groenlandicus) was monitored each winter from 1979-80 through 1986-87. Fecundity in 840 females increased with age from 12% in yearlings to 86% at age 5 years and it did not decline in old (> 11 yr) females. Significant variations occurred among winters and even between two subherds in one winter. Reproductive abnormalities were detected in 2 of 840 females and a probable resorption in 1 of 420 females collected in March. Only about 5% of the fetuses were conceived late, possibly by repeat ovulators. Combining survival and fecundity data yielded age-specific calf production, which indicated that, for example, 54% of calves were born to females 3-6 years old.

scholarly journals Determinants Of Dominance, Resting Place And Neighbour Preferences In Wrzosówka Polska Ewes Kept Indoors

2014 ◽  
Vol 14 (2) ◽  
pp. 365-375 ◽  
Author(s):  
Marcin T. Górecki ◽  
Natalia Dziwińska
Keyword(s):  
Body Weight ◽  
Social Interactions ◽  
Social Behaviour ◽  
Aggressive Behaviour ◽  
Social Rank ◽  
Social Hierarchy ◽  
Social Position ◽  
Physical Contact ◽  
Use Of Space ◽  
The Social

Abstract The aim of this study was to recognize features determining social hierarchy in Wrzosówka Polska ewes kept indoors as well as to investigate their resting place and companionship preferences. Observations (156 hours in total) were carried out in a group of 22 ewes. The social rank of sheep was determined by their age, body weight and length of horns. Social position was positively correlated with aggressive behaviour performed and negatively with aggressive behaviour received. Use of space while resting was influenced by ewe social behaviour; aggressive individuals lied more often in attractive places, namely against walls and fodder troughs compared to other animals. In general, the ewes rested by having physical contact with animals of similar rank and aggressiveness. Kinship appeared not to be important in neighbour preference. As can be concluded, social interactions influenced the use of space and neighbourhood in ewes

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