Mountain goat recruitment: kid production and survival to breeding age

1994 ◽  
Vol 72 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Marco Festa-Bianchet ◽  
Martin Urquhart ◽  
Kirby G. Smith
Keyword(s):  
Nutrient Availability ◽  
Reproductive Performance ◽  
Canis Lupus ◽  
Ursus Arctos ◽  
Survival Rates ◽  
Grizzly Bears ◽  
Oreamnos Americanus ◽  
Felis Concolor ◽  
Mountain Goats ◽  
Mountain Goat

During a 5-year study of a marked population of mountain goats (Oreamnos americanus) in west-central Alberta, 5 of 17 females produced their first kid at 4 years of age, while most females did not reproduce until 5 years of age. Twinning accounted for 2% of births. Survival of kids to 1 year averaged 60%, and survival of females from 1 to 4 years of age was 52%. Most deaths of kids occurred in September–November and appeared due to predation by wolves (Canis lupus), cougars (Felis concolor), and grizzly bears (Ursus arctos). At least half of the yearlings lost from the population were preyed upon, but losses of 2-year-olds were concentrated in the summer, suggesting emigration. Survival rates of young goats were not different according to sex. We suggest that nutrient availability limits the reproductive performance of the goats by retarding their growth, while predation on young goats is a major source of mortality.

Demography of barren-ground grizzly bears

2003 ◽  
Vol 81 (2) ◽  
pp. 294-301 ◽  
Author(s):  
Philip D McLoughlin ◽  
Mitchell K Taylor ◽  
H Dean Cluff ◽  
Robert J Gau ◽  
Robert Mulders ◽  
...  
Keyword(s):  
Survival Rate ◽  
Litter Size ◽  
Birth Interval ◽  
Ursus Arctos ◽  
Survival Rates ◽  
Grizzly Bears ◽  
Adult Males ◽  
Barren Ground ◽  
Rate Of Increase ◽  
The Mean

Between May 1995 and June 1999, we equipped 81 barren-ground grizzly bears (Ursus arctos) with satellite radio collars within a study area of 235 000 km2, centred 400 km northeast of Yellowknife, Northwest Territories, Canada. We used data from radiotelemetry to estimate survival rates, reproductive parameters, and the finite rate of increase of the population (λ). The annual survival rate of adult females was estimated at 0.979 (95% confidence intervals (CI) = 0.955–0.998), while the survival rate of adult males was 0.986 (95% CI = 0.942–1.0). The cub survival rate was 0.737 (95% CI = 0.600–0.844) and the yearling survival rate was 0.683 (95% CI = 0.514–0.821). Cub litter size averaged 2.23 (SE = 0.13, n = 35), while yearling litter size decreased to a mean of 1.86 (SE = 0.12, n = 35). The mean litter size of females with 2-year-olds was 1.85 (SE = 0.15, n = 20). The mean birth interval was 2.8 years (SE = 0.3 years, n = 17). The mean reproductive interval, which is calculated by excluding the loss of whole litters from the sample, was 3.9 years (SE = 0.4 years, n = 9). Mean litter size divided by mean birth interval yielded an annual natality rate of 0.81 cubs per adult female per year. The mean age at first parturition was 8.1 years (SE = 0.5 years, n = 10). We believe the population to be currently stable or slightly increasing (λ = 1.033, 95% CI = 1.008–1.064).

Resource limitation in mountain goats: a test by experimental cropping

1988 ◽  
Vol 66 (1) ◽  
pp. 228-238 ◽  
Author(s):  
D. B. Houston ◽  
V. Stevens
Keyword(s):  
Population Dynamics ◽  
Density Dependence ◽  
National Park ◽  
Resource Limitation ◽  
Oreamnos Americanus ◽  
Olympic National Park ◽  
Fat Reserves ◽  
Goat Population ◽  
Mountain Goats ◽  
Mountain Goat

Changes are reported in the population dynamics and physical condition of mountain goats (Oreamnos americanus) following a reduction in their density at Olympic National Park, Washington, U.S.A. The goat population showed density-dependent responses in initial breeding ages and in litter size. Production and recruitment of kids were more variable at high densities, and these population attributes may show nonlinear density dependence. These shifts in dynamics were associated with increases in live weights and, possibly, in fat reserves. The density dependence shown was insufficient to compensate for removals that approximated the initial production of young, and goat numbers declined precipitously. The implications of these relationships to mountain goat ecology are examined.

Reproductive success in female mountain goats

1991 ◽  
Vol 69 (12) ◽  
pp. 2956-2961 ◽  
Author(s):  
James A. Bailey
Keyword(s):  
Reproductive Success ◽  
Observational Studies ◽  
Rocky Mountain ◽  
Individual Characteristics ◽  
Extrinsic Factors ◽  
Oreamnos Americanus ◽  
Intrinsic Factors ◽  
Mountain Goats ◽  
Mountain Goat

Kid production by marked females, age ratios from a 24-year study, and the literature are used to evaluate hypotheses that three intrinsic and three extrinsic factors affect reproduction by female Rocky Mountain goats (Oreamnos americanus). On Sheep Mountain – Gladstone Ridge, Colorado, mountain goat age ratios declined while the herd grew during 1966–1979, and continued to decline with population stability during 1980–1989, suggesting a continued increase in ecological density of goats 39 years after they were introduced in 1950. Among intrinsic factors, age and persisting individual characteristics have influenced reproductive success of females. Reproductive success in any year has not limited success in the following year, except in 4-year-olds. Among extrinsic factors, reproductive success of female mountain goats has been negatively influenced by density or ecological density and by snowpack during gestation. Reproductive success of females may have been positively influenced by snowpack that enhanced forage conditions prior to breeding. The relative importance of these six factors in determining reproductive success of females may vary among and (temporally) within herds. Most hypotheses regarding reproductive success in female mountain goats remain poorly tested. Short-term observational studies hold little promise for testing hypotheses, owing to large among-years variation in reproductive success. Long-term, intensive observational studies, or manipulative experiments, are suggested.

scholarly journals Does reduced heterozygosity influence dispersal? A test using spatially structured populations in an alpine ungulate

2011 ◽  
Vol 7 (3) ◽  
pp. 433-435 ◽  
Author(s):  
Aaron B. A. Shafer ◽  
Jocelyn Poissant ◽  
Steeve D. Côté ◽  
David W. Coltman
Keyword(s):  
Population Monitoring ◽  
Structured Populations ◽  
Potential Cost ◽  
Opposite Pattern ◽  
Oreamnos Americanus ◽  
Long Term Study ◽  
Spatially Structured Populations ◽  
Mountain Goats ◽  
Mountain Goat

Despite having a profound effect on population dynamics, the reasons that animals disperse are poorly understood. Evolutionary explanations have focused on inbreeding and competition, where the potential cost of philopatry is negated through dispersal. Such scenarios lead to the prediction that less successful individuals preferentially disperse, termed ‘fitness-associated dispersal’. Since heterozygosity is associated with fitness, we assessed whether dispersed animals had less observed heterozygosity ( H O ) than residents. We tested this prediction using both genetic and population-monitoring data of mountain goats ( Oreamnos americanus ). Individuals classified as dispersers through cross-assignment had the lowest mean H O , followed by residents, and then admixed individuals. Dispersed individuals had 6.3 per cent less H O than their subpopulation of origin. In the long-term study of the mountain goat herd at Caw Ridge, Alberta, immigrants had the lowest H O ; however, the opposite pattern was seen in emigrants, which may be related to density dependence. This study is the first to provide empirical evidence that heterozygosity is associated with dispersal.

Estimating population growth of grizzly bears from the Flathead River drainage using computer simulations of reproduction and survival rates

1996 ◽  
Vol 74 (8) ◽  
pp. 1409-1416 ◽  
Author(s):  
Frederick W. Hovey ◽  
Bruce N. McLellan
Keyword(s):  
Ursus Arctos ◽  
Survival Rates ◽  
Population Increase ◽  
Grizzly Bears ◽  
Grizzly Bear ◽  
Reproduction Rate ◽  
River Drainage ◽  
The North ◽  
Flathead River ◽  
Subadult Female

Using survival and reproduction data obtained from radio-tracking 23 adult female, 24 subadult female, 49 yearling, and 44 cub grizzly bears (Ursus arctos) in the Flathead River drainage of British Columbia and Montana, we estimated the finite rate of population increase [Formula: see text] from 1979 to 1994 at 1.085 ± 0.026, with ≈95% confidence limits of 1.032–1.136. Estimated annual survival rates were 0.946 ± 0.026 for adult females, 0.931 ± 0.038 for subadult females, 0.944 ± 0.039 for yearlings, and 0.867 ± 0.050 for cubs (rates for cubs and yearlings represented both sexes). The estimated annual reproduction rate and age at first parturition were 0.422 ± 0.042 female cubs per female and 6.44 ± 0.45 years, respectively. We found that uncertainty in [Formula: see text] was mostly attributable to uncertainty in survival rates (76.7%), with subadult (47.5%) and adult (21.9%) survival contributing the largest portions. These results indicated that to reduce uncertainty in [Formula: see text], further research on grizzly bears in our study area should focus on improving estimates of adult and subadult female survivorship. Other demographic variables are not as important in estimating the grizzly bear population trend in the North Fork of the Flathead River drainage.

scholarly journals Mineral Lick Visitation by Mountain Goats, Oreamnos americanus

2010 ◽  
Vol 124 (3) ◽  
pp. 225 ◽  
Author(s):  
Clifford G. Rice
Keyword(s):  
Short Duration ◽  
Oreamnos Americanus ◽  
Gps Collars ◽  
Long Duration ◽  
Mountain Goats ◽  
Global Positioning ◽  
Mineral Licks ◽  
Mountain Goat ◽  
Administrative Units ◽  
Mineral Lick

Many species, including Mountain Goats (Oreamnos americanus), are known to visit mineral licks, but the extent and duration of use are poorly understood because most studies consist of observations at licks. I studied the movements to, from, and near mineral licks of 11 mountain goats in Washington wearing Global Positioning System (GPS) collars for a total of 169 goat-months of tracking and evaluated chemical composition of six mineral licks compared with reference soil samples. I recorded 101 mineral lick visits to 13 mineral licks. Each GPS fix was classified as moving toward a mineral lick, in the vicinity of a lick, on an excursion from a lick, moving away from a lick, or not associated with lick use. Depending on annual movement patterns associated with lick use, each Mountain Goat was classified as a Migrant (single lick visit of long duration, n = 3 Mountain Goats), Sojourner (few visits of short duration, n = 2), Commuter (many visits of short duration, n = 5), or Resident (lick within normal range of movements, n = 1). Most mineral lick visits took place 01 June-15 August with peak visitation about 14 June-29 July. Migrants typically stayed in the vicinity of licks about a month (but as long as 51 days) whereas other mountain goats visited licks for 0.1-8 days (median = 1 day). Migrants also tended to take longer and move farther than other Mountain Goats when on movements to and from licks. Most Mountain Goats moved toward mineral licks faster (km/hr) than they moved away from licks. All licks had higher concentrations of sodium than reference samples (1.5-27 times as high), although concentrations of calcium, potassium, and sulphate tended to be higher as well, whereas magnesium was not. Mineral lick visitation has costs (energetics of travel, reduced forage, and predation risk). Depending on the importance of these costs, mountain goats evidently use various strategies for exploiting mineral licks as exemplified by the movement types (migrant, sojourner, commuter, or resident). Notably, most of the Mountain Goats in this study crossed national forest, county and Washington Department of Fish and Wildlife region boundaries to another to visit mineral licks. Thus, coordination among administrative units is needed in management of Mountain Goats and mineral licks they use.

Geophagic behavior in the mountain goat (Oreamnos americanus): support for meeting metabolic demands

2015 ◽  
Vol 93 (8) ◽  
pp. 599-604 ◽  
Author(s):  
B.L. Slabach ◽  
T.B. Corey ◽  
J.R. Aprille ◽  
P.T. Starks ◽  
B. Dane
Keyword(s):  
Logistic Regression ◽  
Mountain Range ◽  
High Fidelity ◽  
Field Observations ◽  
Nutrient Supplementation ◽  
Oreamnos Americanus ◽  
Mineral Supplementation ◽  
Mountain Goats ◽  
Mountain Goat ◽  
Coastal Mountain

Geophagy, the intentional consumption of earth or earth matter, occurs across taxa. Nutrient and mineral supplementation is most commonly cited to explain its adaptive benefits; yet many specific hypotheses exist. Previous research on mountain goats (Oreamnos americanus (Blainville, 1816)) broadly supports nutrient supplementation as the adaptive benefit of geophagy. Here, we use data from an undisturbed population of mountain goats inhabiting a geologically distinct coastal mountain range in southwestern British Columbia to test the hypothesis that geophagic behavior is a proximate mechanism for nutrient supplementation to meet metabolic demands. Our population, observed for over 30 consecutive years, returned each year with high fidelity to the same geophagic lick sites. Logistic regression demonstrated an overall effect of sodium and phosphorus, but not magnesium and calcium, on lick preferences. These data, in conjunction with field observations, provide support for the hypothesis that geophagy provides nutrient supplementation and that geophagy may be an obligate behavior to meet necessary metabolic demands within this population. The implications of our results suggest the necessity to preserve historically important habitats that may be necessary for population health.

Glutathione peroxidase activity and selenium levels in Rocky Mountain bighorn sheep and mountain goats

1989 ◽  
Vol 67 (10) ◽  
pp. 2493-2496 ◽  
Author(s):  
Judith Samson ◽  
Jon T. Jorgenson ◽  
W. D. Wishart
Keyword(s):  
Glutathione Peroxidase ◽  
Clinical Signs ◽  
Rocky Mountain ◽  
Selenium Deficiency ◽  
Bighorn Sheep ◽  
Ovis Canadensis ◽  
Domestic Sheep ◽  
Oreamnos Americanus ◽  
Mountain Goats ◽  
Mountain Goat

Selenium levels and glutathione peroxidase (GSH-Px) activity were determined in the blood of wild and captive herds of bighorn sheep (Ovis canadensis), as well as in one wild mountain goat (Oreamnos americanus) herd. No significant relationship was established between blood selenium and GSH-Px activity for individual herds of bighorns, but when all herds were pooled, selenium was significantly (P < 0.01) correlated with GSH-Px. The hypothesis that bighorn sheep would exhibit higher GSH-Px activity per unit of blood selenium than domestic cattle was not supported. One bighorn population had blood selenium levels below those considered deficient in domestic sheep, yet exhibited no clinical signs of selenium deficiency. A blood selenium by GSH-Px relationship did not exist for the single mountain goat herd sampled. The seven blood samples collected from mountain goats did not differ from those from bighorn sheep in their GSH-Px activity relative to blood selenium levels.

Dynamics of a grizzly bear population during a period of industrial resource extraction. II. Mortality rates and causes of death

1989 ◽  
Vol 67 (8) ◽  
pp. 1861-1864 ◽  
Author(s):  
Bruce N. McLellan
Keyword(s):  
Outdoor Recreation ◽  
Ursus Arctos ◽  
Survival Rates ◽  
Timber Harvest ◽  
Easy Access ◽  
Resource Extraction ◽  
Grizzly Bears ◽  
Grizzly Bear ◽  
Human Intervention ◽  
Management Actions

The causes and rates of grizzly bear (Ursus arctos) mortality in a radio-marked population in southeastern British Columbia were studied for 9 years during a period of timber harvest, gas exploration, and outdoor recreation, including grizzly hunting. During 110 bear-years of radio tracking 55 radio-collared grizzly bears and their dependent offspring, one bear with a functioning radio collar died from natural causes and eight others from human intervention; in addition, four dependent offspring were thought to have died. Excluding trap-related mortalities, the best estimate for the annual survival rates were as follows: 0.82 for cubs, 0.88 for yearlings, 0.93 for subadults, and 0.93 for adults. Of the eight bears killed by human intervention, two were killed by legal harvest, five by illegal harvest (one of these in a trap), and one was killed in a trap by another bear. No mortalities were directly attributable to industrial activities. Resource extraction industries do contribute to grizzly bear mortality indirectly through the construction of roads, which provide easy access to hunters, poachers, and settlers. Road access planning and postoperational control of vehicles are recommended management actions.

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