Dynamics of woodland caribou populations at the southern limit of their range in Saskatchewan

1998 ◽  
Vol 76 (2) ◽  
pp. 251-259 ◽  
Author(s):  
W James Rettie ◽  
François Messier
Keyword(s):  
Rangifer Tarandus ◽  
Ursus Americanus ◽  
Road Construction ◽  
Black Bear ◽  
Woodland Caribou ◽  
Serum Progesterone ◽  
Southern Limit ◽  
Disjunct Populations ◽  
Calf Survival ◽  
Proximate Causes

Woodland caribou (Rangifer tarandus caribou) in central Saskatchewan are aggregated into several spatially disjunct populations. Historical data indicate that some local populations were eliminated and that the regional metapopulation declined during the 1970s. Proximate causes of decline may have included hunting, severe winter weather, and the end of predator control, though the ultimate causes may relate to road construction and logging activity, which expanded after 1966. There has been no sport hunting since 1987, yet the caribou populations in the region appear to be declining. Based on serum progesterone levels, first conception by females occurred at 16 months and the overall pregnancy rate was 94%, and in addition the minimum parturition rate was 86%, all of which indicate adequate nutrition. The annual survival rate of adults was 84%, which is comparatively low, though similar to results from other studies on woodland caribou. We observed a low rate of calf recruitment (28 calves : 100 cows), which we suspect was due to predation. Wolves (Canis lupus) have long been thought to limit woodland caribou populations while subsisting on other ungulate prey, but we speculate that black bear (Ursus americanus) predation may be an important cause of poor calf survival.

Spring diet of American black bears (Ursus americanus) in a moose (Alces alces) – woodland caribou (Rangifer tarandus caribou) system in northern Ontario, Canada

2021 ◽  
pp. 721-728
Author(s):  
A.A.D. McLaren ◽  
S.E. Jamieson ◽  
M. Bond ◽  
A.R. Rodgers ◽  
B.R. Patterson
Keyword(s):  
Rangifer Tarandus ◽  
Ursus Americanus ◽  
Alces Alces ◽  
Black Bear ◽  
Black Bears ◽  
Rangifer Tarandus Caribou ◽  
Woodland Caribou ◽  
Northern Ontario ◽  
American Black ◽  
American Black Bears

American black bears (Ursus americanus Pallas, 1780) are opportunistic foragers, and across most of their range in North America, their diet is predominantly vegetation with limited consumption of vertebrates and invertebrates. However, they are also predators of ungulates, especially neonates, with regional variation in the amount of predation pressure they exert. We used scat analysis to examine the diet of black bears during the calving season in a moose (Alces alces (Linnaeus, 1758)) – woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) system in the Boreal forest of northern Ontario, Canada. Bears consumed herbaceous plants (46.5%), fruits and (or) seeds (20.0%), moose (3.3% adults; 4.3% calves), American beaver (Castor canadensis Kuhl, 1820; 8.5%), and insects (mostly ants; 4.2%). Bears had the highest consumption of moose and beaver in early spring, before switching to a more vegetation-dominated diet. We did not detect evidence of caribou consumption. Based on our results, black bear consumption of moose, particularly neonates, may warrant further investigation.

Serum progesterone, oestradiol, luteinizing hormone and prolactin profiles in the female black bear (Ursus americanus)

1998 ◽  
Vol 53 (1-4) ◽  
pp. 107-118 ◽  
Author(s):  
T Tsubota ◽  
L Howell-Skalla ◽  
W.R Boone ◽  
D.L Garshelis ◽  
J.M Bahr
Keyword(s):  
Luteinizing Hormone ◽  
Ursus Americanus ◽  
Black Bear ◽  
Serum Progesterone

scholarly journals Intrinsic traits of woodland caribou Rangifer tarandus caribou calves depredated by black bears Ursus americanus and coyotes Canis latrans

2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
Matthew A. Mumma ◽  
Guillaume Bastille-Rousseau ◽  
Steve E. Gullage ◽  
Colleen E. Soulliere ◽  
Shane P. Mahoney ◽  
...  
Keyword(s):  
Rangifer Tarandus ◽  
Ursus Americanus ◽  
Canis Latrans ◽  
Black Bears ◽  
Rangifer Tarandus Caribou ◽  
Woodland Caribou

Habitat selection and spatial relationships of black bears (Ursus americanus) with woodland caribou (Rangifer tarandus caribou) in northeastern Alberta

2011 ◽  
Vol 89 (4) ◽  
pp. 267-277 ◽  
Author(s):  
A.D.M. Latham ◽  
M.C. Latham ◽  
M.S. Boyce
Keyword(s):  
Habitat Selection ◽  
Adult Female ◽  
Rangifer Tarandus ◽  
Ursus Americanus ◽  
Black Bears ◽  
Spatial Relationships ◽  
Rangifer Tarandus Caribou ◽  
Woodland Caribou ◽  
Management Actions ◽  
Northeastern Alberta

Populations of woodland caribou ( Rangifer tarandus caribou (Gmelin, 1788)) have declined across much of their range. Wolves ( Canis lupus L., 1758) are believed to be responsible for the majority of mortality in adult female caribou; however, we hypothesize that other predators such as black bears ( Ursus americanus Pallas, 1780) may be important contributors to calf mortality. We assessed habitat selection by black bears and spatial relationships of caribou – black bears during the caribou calving season in northeastern Alberta, Canada. Black bears avoided bogs and fens, while selecting upland mixed woods and various industrial features. Conversely, caribou showed strong selection for bogs and fens relative to bears, supporting the hypothesis that caribou in the boreal forest attempt to minimize predation risk by selecting peatlands to avoid areas frequented by predators. However, habitat selection by individual black bears was highly variable and some bears selected habitats similar to those selected by caribou, i.e., bogs and fens. Bears that specialize on foraging in peatlands might be responsible for some of the predation on caribou calves. Because declines in caribou populations have resulted from a combination of high adult female and calf mortalities, management actions to conserve woodland caribou should consider the entire suite of potential predators rather than focusing only on wolves.

Seasonal serum glucose, progesterone, and Cortisol levels of black bears (Ursus americanus)

1990 ◽  
Vol 68 (1) ◽  
pp. 183-187 ◽  
Author(s):  
Henry J. Harlow ◽  
Thomas D. I. Beck ◽  
Lisa M. Walters ◽  
Shelley S. Greenhouse
Keyword(s):  
Ursus Americanus ◽  
Black Bear ◽  
Serum Cortisol ◽  
Serum Glucose ◽  
Black Bears ◽  
Stress Exposure ◽  
Summer Period ◽  
Serum Progesterone ◽  
Fat Reserves ◽  
Different Seasons

Sixty-two black bears were captured at different seasons during the years 1983–1987. Bears were anesthetized in their dens during the winter and parts of the fall and spring, while bears captured during the summer were snared prior to anesthesia. Radioimmunoassays for both Cortisol and progesterone were validated on black bear serum. An improved, rapid progesterone radioimmunoassay for black bear serum is reported. Serum glucose demonstrated a tendency for reduction during spring. Serum progesterone levels did not demonstrate seasonal differences and were significantly higher in females only during the summer ovulatory/postestrus period. Serum Cortisol was significantly elevated during the winter denning period as compared with the summer period. We conclude that differences in serum progesterone, Cortisol, and glucose may not be indicators of stress exposure, but of seasonal reproductive states and metabolic utilization of fat reserves.

scholarly journals Black Bear, Ursus americanus, Ecology on the Northeast Coast of Labrador

2005 ◽  
Vol 119 (2) ◽  
pp. 164
Author(s):  
Keith Chaulk ◽  
Soren Bondrup-Nielsen ◽  
Fred Harrington
Keyword(s):  
Goodness Of Fit ◽  
Rangifer Tarandus ◽  
Ursus Americanus ◽  
Black Bear ◽  
Goodness Of Fit Test ◽  
Chi Square ◽  
Gps Collars ◽  
Location Data ◽  
Adult Females ◽  
Body Sizes

Twenty-three Black Bears (Ursus americanus) were captured, 20 were measured, marked and/or radio collared, in northeastern Labrador, between 1996 and 1997. Bears used sea ice for travel, coastal islands for denning, hunted adult Caribou (Rangifer tarandus), and were the possible cause of Moose (Alces alces) calf mortality. Body sizes were small, median weight of adult females was 48 kg, and the sex ratio for captured subjects was 1:1. Four of six radio-collared females gave birth during the winter of 1997, female reproductive histories suggest delayed sexual maturity. Den entry occurred between October and December 1996; spring emergence occurred between April and May 1997, with estimated denning period ranging from 148-222 days. Visual observations of habitat use by radio collared subjects (n = 10) were not tested statistically but suggest that barren areas are used nearly as much as forest. Location data from three GPS collars deployed on three adult females were analysed using Chi-square goodness-of-fit test with Bonferroni correction; two females appeared to prefer forest habitats (p < 0.05).

scholarly journals Little Smoky Woodland Caribou Calf Survival Enhancement Project

Rangifer ◽  
2011 ◽  
Vol 31 (2) ◽  
pp. 97 ◽  
Author(s):  
Kirkby G. Smith ◽  
Lois Pittaway
Keyword(s):  
At Risk ◽  
Landscape Change ◽  
Rangifer Tarandus ◽  
Mortality Rates ◽  
Woodland Caribou ◽  
Pregnant Females ◽  
The Past ◽  
West Central ◽  
Calf Survival ◽  
In Captivity

The Little Smoky woodland caribou (Rangifer tarandus) herd is a boreal ecotype located in west central Alberta, Canada. This herd has declined steadily over the past decade and is currently thought to number approximately 80 animals. Factors contributing to the herds' decline appear related to elevated predator-caused mortality rates resulting from industrial caused landscape change. At current rates of decline, the herd is at risk of extirpation. A calf survival enhancement project was initiated in the first half of 2006 as a means of enhancing recruitment while other longer-term approaches were implemented. A total of 10 pregnant females were captured in early March and held in captivity until all calves were at least 3 weeks old. Before release, calves were radiocollared with expandable drop-off collars. Following release, survival of mother and offspring were tracked at intervals until the fall rut. Survival of penned calves was compared to "wild-born" calves at heel of non captive radiocollared females. This approach is compared to other techniques designed to increase recruitment in caribou.

Reducing Human-Bear Conflicts: Bear-Resistant Trash Cans

EDIS ◽  
2017 ◽  
Vol 2017 (3) ◽  
Author(s):  
Ethan T. Noel ◽  
Elizabeth F. Pienaar ◽  
Mike Orlando
Keyword(s):  
Great Risk ◽  
Ursus Americanus ◽  
Black Bear ◽  
Food Sources ◽  
Vehicle Collisions ◽  
Wildlife Ecology ◽  
Human Food ◽  
Fact Sheet

The Florida black bear (Ursus americanus floridanus) is the only species of bear in Florida, with an estimated population of approximately 4,030 bears. Bears that eat garbage put themselves in danger. This 3-page fact sheet written by Ethan T. Noel, Elizabeth F. Pienaar, and and Mike Orlando and published by the Wildlife Ecology and Conservation Department explains how to secure human garbage from bears so that they don’t become reliant on human food sources, a condition that puts them at great risk of being killed from vehicle collisions, illegal shooting, or euthanasia.­http://edis.ifas.ufl.edu/uw429

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