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Ecology of desert bighorn sheep in Colorado

dc.contributor.authorCreeden, Paul J., author
dc.contributor.authorCook, Robert S., advisor
dc.contributor.authorBailey, James A., committee member
dc.contributor.authorEllenberger, John H., committee member
dc.contributor.authorLehner, Philip N., committee member
dc.date.accessioned2021-09-23T21:30:10Z
dc.date.available2021-09-23T21:30:10Z
dc.date.issued1986
dc.description.abstractDesert bighorn sheep (Ovis canadensis nelsoni & mexicana) were transplanted into western Colorado in 1979, 1980 and 1981. The ecology of these sheep following transplanting was studied during 1982 and 1983. The population increased 18%, from 34 to 40 sheep, during this period. Minimum natality rates of 71% and 75% were observed. Survival of lambs born in 1982 to 1 year of age was at least 70%. Three of 4 suspected lamb losses occurred during the fall and winter months. Five adult mortalities were recorded. Two of these were predator related and occurred within the first few months of transplanting. Timing of reproductive activities was significantly delayed during the first year following transplanting. Ewes bred in Arizona and transplanted to Colorado in 1981 lambed significantly earlier in 1982 than they did in 1983 after breeding in Colorado. During 1982, ewes from the 1979 and 1980 transplants lambed significantly later than the ewes released in 1981. No significant differences in reproductive seasons were evident between transplant groups during 1983. Ewes preferred inner-canyon habitats for lambing. They most often selected ledges at the bases of sheer canyon walls and above steep talus slopes. All sites were located on escape terrain. A moderate degree of fidelity of ewes to lambing sites used in previous years was observed. The seclusion period of ewes during the lambing season varied with the social status of individual ewes. Dominant females remained alone for less time, both before and after parturition, than did subordinate females. Movements of ewes with lambs following parturition varied with the ewe's home range size. Long-distance moves were first recorded with 2-week old lambs. Dispersal of sheep following transplanting appeared to be influenced by winter weather conditions and by association with other bighorn. Both factors seemed to decrease movements. Dispersal patterns exhibited immediately following release influenced ultimate home range size. Sheep released in 1981 centered activities around the areas explored initially following transplanting. Overlapping home ranges were observed for both rams and ewes, p ranging in size from 4.6 to 44.7 km2. Home range sizes of ewes varied significantly among release groups and with habitat-use patterns. Coefficients of association were generally low in the herd. Bighorn ewes associated in direct proportion with the amount of range shared. Bighorn use of aspect differed between the winter-spring and summer periods. Use of inner-canyon habitats appeared to be related to canopy coverage of trees and shrubs.
dc.format.mediummasters theses
dc.identifier.urihttps://hdl.handle.net/10217/233929
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado State University. Libraries
dc.relationCatalog record number (MMS ID): 991008515309703361
dc.relationQL737.U53 C74 1986
dc.relation.ispartof1980-1999
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.
dc.subject.lcshBighorn sheep
dc.subject.lcshAnimal ecology -- Colorado
dc.titleEcology of desert bighorn sheep in Colorado
dc.typeText
dcterms.rights.dplaThis Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
thesis.degree.disciplineFishery and Wildlife Biology
thesis.degree.grantorColorado State University
thesis.degree.levelMasters
thesis.degree.nameMaster of Science (M.S.)

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