Behavioural reactions of bighorn sheep ( Ovis canadensis ) to cougar ( Puma concolor ) attacks / Comportement du mouflon d'Amerique ( Ovis canadensis ) lors d'attaques par le cougar ( Puma concolor )

Mammalia ◽  
2006 ◽  
Vol 70 (1-2) ◽  
Author(s):  
Fanie Pelletier ◽  
Yannick Gendreau ◽  
Chiarastella Feder
Keyword(s):  
Puma Concolor ◽  
Bighorn Sheep ◽  
Ovis Canadensis

scholarly journals Predation impedes recovery of Sierra Nevada bighorn sheep

2021 ◽  
pp. 444-470
Author(s):  
Daniel J. Gammons ◽  
Jeffrey L. Davis ◽  
David W. German ◽  
Kristin Denryter ◽  
John D. Wehausen ◽  
...  
Keyword(s):  
Population Growth ◽  
Sierra Nevada ◽  
Puma Concolor ◽  
Population Decline ◽  
Survival Rates ◽  
Bighorn Sheep ◽  
Ovis Canadensis ◽  
Management Actions ◽  
Near Future ◽  
Ovis Canadensis Sierrae

Translocation of animals into formerly occupied habitat is a key element of the recovery plan for Sierra Nevada bighorn sheep (Ovis canadensis sierrae), which are state (California) and federally listed as endangered. However, implementing Sierra bighorn translocations is a significant conservation challenge because of the small size of the extant population and the limited number of herds available to donate translocation stock. One such herd, the Mt. Langley herd, recently became unusable as a translocation source following a substantial population decline. At the time of listing in 1999, predation by mountain lions (Puma concolor; hereafter lion) was considered a primary threat to Sierra bighorn, and since then lion predation may have continued to limit the ability of source herds to provide translocation stock. We evaluated the relationship between lion predation and ewe survival rates within three source herds of the Southern Recovery Unit, compared lion abundance and ewe survival among years of varying predation levels, provided a range of estimated times for the Mt. Langley herd to recover to its former status as a translocation source, and determined if the rates lions have been removed to mitigate Sierra bighorn predation exceeded sustainable harvest guidelines. We found compelling evidence that lion predation has impeded the recovery of Sierra bighorn by reducing survival rates of adult ewes (and consequently, population growth) and by preying upon individuals that could have otherwise been translocated. Ewe survival was poor during years of extreme predation but even during years of typical predation, survival rates were below a level needed to ensure population growth, indicating that years with little or no lion predation may be necessary for the population to grow and meet recovery goals. Because the intensity of predation was related to lion abundance, monitoring lion populations could provide managers with advance warning of periods of extreme predation. We found that following a period of particularly extreme predation, the Mt. Langley herd decreased in abundance far below the threshold needed to be considered a source of translocation stock, resulting in the loss of approximately 25% of the recovery program’s capacity for translocations. It is unclear how many years it will take for this herd to recover, but management actions to reduce lion predation are likely needed for this herd to grow to a size that can afford to donate individuals to translocation efforts in the near future, even when optimistic growth rates are assumed. We found that lion removal may also be needed to prevent predation from leading to Sierra bighorn population decline. Lion removal rates that have been implemented thus far are well below what would be needed to reduce the abundance the eastern Sierra lion population itself. We recommend continued monitoring of Sierra bighorn and sympatric lions and note that lion removal may be required to facilitate bighorn recovery for the foreseeable future.

Cougar predation on bighorn sheep in southwestern Alberta during winter

1997 ◽  
Vol 75 (5) ◽  
pp. 771-775 ◽  
Author(s):  
P. Ian Ross ◽  
Martin G. Jalkotzy ◽  
Marco Festa-Bianchet
Keyword(s):  
Small Groups ◽  
Puma Concolor ◽  
Bighorn Sheep ◽  
Ovis Canadensis ◽  
Sheep Population ◽  
Specialist Predators

Predation by cougars (Puma concolor) upon bighorn sheep (Ovis canadensis) was studied in southwestern Alberta during winters from 1985–1986 to 1993–1994. We examined 320 kills and found that ungulates provided >99% of the biomass consumed by cougars in November–April. All ungulate species found within the study area were taken by cougars. Predation on bighorn sheep varied greatly from year to year; cougars were known to kill 0–13% of the November sheep population, and 0–57% of over-winter sheep mortality consisted of known cougar kills. Of 29 bighorns killed by cougars, 13 were lambs. The remainder ranged in age from 1 to 17 years and included 9 ewes and 7 rams. Cougar predation on bighorn sheep appears to be largely an individual, learned behaviour; most cougars rarely killed sheep, but some preyed heavily upon them. One female killed 9% of the population and 26% of the lambs over a single winter. For mountain-dwelling ungulates that occur in small groups, the presence of one or a few individual specialist predators may strongly and unpredictably influence demography and behaviour.

scholarly journals Genetic Analysis of Scats Reveals Minimum Number and Sex of Recently Documented Mountain Lions

2011 ◽  
Vol 2 (1) ◽  
pp. 106-111 ◽  
Author(s):  
Ashwin Naidu ◽  
Lindsay A. Smythe ◽  
Ron W. Thompson ◽  
Melanie Culver
Keyword(s):  
Puma Concolor ◽  
Bighorn Sheep ◽  
Camera Trap ◽  
Ovis Canadensis ◽  
National Wildlife Refuge ◽  
Desert Bighorn Sheep ◽  
Mountain Lions ◽  
Mountain Lion ◽  
Minimum Number ◽  
Genetic Techniques

Abstract Recent records of mountain lions Puma concolor and concurrent declines in desert bighorn sheep Ovis canadensis mexicana on Kofa National Wildlife Refuge in Arizona, United States, have prompted investigations to estimate the number of mountain lions occurring there. We performed noninvasive genetic analyses and identified species, individuals, and sex from scat samples collected from the Kofa and Castle Dome Mountains. From 105 scats collected, we identified a minimum of 11 individual mountain lions. These individuals consisted of six males, two females and three of unknown sex. Three of the 11 mountain lions were identified multiple times over the study period. These estimates supplement previously recorded information on mountain lions in an area where they were historically considered only transient. We demonstrate that noninvasive genetic techniques, especially when used in conjunction with camera-trap and radiocollaring methods, can provide additional and reliable information to wildlife managers, particularly on secretive species like the mountain lion.

scholarly journals Brucellosis in Captive Rocky Mountain Bighorn Sheep (Ovis canadensis) Caused by Brucella abortus Biovar 4

2004 ◽  
Vol 40 (2) ◽  
pp. 311-315 ◽  
Author(s):  
Terry J. Kreeger ◽  
Walter E. Cook ◽  
William H. Edwards ◽  
Todd Cornish
Keyword(s):  
Brucella Abortus ◽  
Rocky Mountain ◽  
Bighorn Sheep ◽  
Ovis Canadensis

scholarly journals Desert Bighorn Sheep: Changes in Genetic Variation Over Time and the Impact of Merging Populations

2014 ◽  
Vol 5 (1) ◽  
pp. 3-13 ◽  
Author(s):  
Philip W. Hedrick ◽  
John D. Wehausen
Keyword(s):  
Genetic Variation ◽  
New Mexico ◽  
Monitoring And Evaluation ◽  
Bighorn Sheep ◽  
Ovis Canadensis ◽  
Mexican Population ◽  
Desert Bighorn Sheep ◽  
Two Generations ◽  
The Impact ◽  
Over Time

Abstract Founder effects, genetic bottlenecks, and genetic drift in general can lead to low levels of genetic diversity, which can influence the persistence of populations. We examine genetic variation in two populations of desert bighorn sheep Ovis canadensis from New Mexico and Mexico to measure change over time and evaluate the impact of introducing individuals from one population into the other. Over about three generations, the amount of genetic variation in the New Mexico population increased. In contrast, over about two generations the amount of genetic variation in the Mexican population decreased by a great extent compared with an estimate from another Mexican population from which it is primarily descended. The potential reasons for these changes are discussed. In addition, although both populations have low genetic variation, introduction of Mexican rams into the New Mexico population might increase the amount of genetic variation in the New Mexico population. Overall, it appears that management to increase genetic variation might require substantial detailed monitoring and evaluation of ancestry from the different sources and fitness components.

Factors influencing heart rate in free-ranging bighorn sheep: a physiological approach to the study of wildlife harassment

1979 ◽  
Vol 57 (10) ◽  
pp. 2010-2021 ◽  
Author(s):  
Robert A. MacArthur ◽  
Ronald H. Johnston ◽  
Valerius Geist
Keyword(s):  
Bighorn Sheep ◽  
Ovis Canadensis ◽  
Activity Level ◽  
Base Line ◽  
Vehicular Traffic ◽  
Behavioral Reactions ◽  
Factors Influencing ◽  
Close Range ◽  
Physiological Approach ◽  
Free Ranging

The telemetered heart rates (HR) of unrestrained female bighorn sheep (Ovis canadensis canadensis) were recorded under various behavioral and environmental circumstances. In all ewes HR varied positively with activity level and inversely with distance to a road traversing the study area. The HR recorded from animals moving at night or through timber by day were higher than during daytime movement across open slopes.Responses to transient stimuli varied greatly. The appearance of free-ranging canids evoked maximal increases in HR in all ewes. Vehicular traffic and aircraft elicited HR responses only at close range (< 200 m). Most (78.1%) HR responses to disturbing stimuli preceded or occurred in the absence of overt behavioral reactions. The HR usually peaked within 60 s of the onset of the response and recovered to predisturbance base line in less than 200 s. The appearance and continued presence (1–10 min) of a human within 50 m of the sheep resulted in a 20% rise in mean HR. The significance of these findings is discussed in relation to the behavior, ecology, and bioenergetics of bighorn sheep.

scholarly journals Differences in leukocyte differentiation molecule abundances on domestic sheep (Ovis aries) and bighorn sheep (Ovis canadensis) neutrophils identified by flow cytometry

2016 ◽  
Vol 46 ◽  
pp. 40-46 ◽  
Author(s):  
Margaret A. Highland ◽  
David A. Schneider ◽  
Stephen N. White ◽  
Sally A. Madsen-Bouterse ◽  
Donald P. Knowles ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Bighorn Sheep ◽  
Ovis Canadensis ◽  
Ovis Aries ◽  
Domestic Sheep

scholarly journals Linking population performance to nutritional condition in an alpine ungulate

2020 ◽  
Vol 101 (5) ◽  
pp. 1244-1256 ◽  
Author(s):  
Thomas R Stephenson ◽  
David W German ◽  
E Frances Cassirer ◽  
Daniel P Walsh ◽  
Marcus E Blum ◽  
...  
Keyword(s):  
Body Fat ◽  
Bighorn Sheep ◽  
Nutritional Condition ◽  
Ovis Canadensis ◽  
Population Increase ◽  
Overwinter Survival ◽  
Fat Reserves ◽  
Adult Females ◽  
Free Body

Abstract Bighorn sheep (Ovis canadensis) can live in extremely harsh environments and subsist on submaintenance diets for much of the year. Under these conditions, energy stored as body fat serves as an essential reserve for supplementing dietary intake to meet metabolic demands of survival and reproduction. We developed equations to predict ingesta-free body fat in bighorn sheep using ultrasonography and condition scores in vivo and carcass measurements postmortem. We then used in vivo equations to investigate the relationships between body fat, pregnancy, overwinter survival, and population growth in free-ranging bighorn sheep in California and Nevada. Among 11 subpopulations that included alpine winter residents and migrants, mean ingesta-free body fat of lactating adult females during autumn ranged between 8.8% and 15.0%; mean body fat for nonlactating females ranged from 16.4% to 20.9%. In adult females, ingesta-free body fat &gt; 7.7% during January (early in the second trimester) corresponded with a &gt; 90% probability of pregnancy and ingesta-free body fat &gt; 13.5% during autumn yielded a probability of overwinter survival &gt; 90%. Mean ingesta-free body fat of lactating females in autumn was positively associated with finite rate of population increase (λ) over the subsequent year in bighorn sheep subpopulations that wintered in alpine landscapes. Bighorn sheep with ingesta-free body fat of 26% in autumn and living in alpine environments possess energy reserves sufficient to meet resting metabolism for 83 days on fat reserves alone. We demonstrated that nutritional condition can be a pervasive mechanism underlying demography in bighorn sheep and characterizes the nutritional value of their occupied ranges. Mountain sheep are capital survivors in addition to being capital breeders, and because they inhabit landscapes with extreme seasonal forage scarcity, they also can be fat reserve obligates. Quantifying nutritional condition is essential for understanding the quality of habitats, how it underpins demography, and the proximity of a population to a nutritional threshold.

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