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Description: |
xii, 121 leaves : illustrations ; 28 cm |
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Dissertation Note: |
Ph. D. Utah State University. Dept. of Wildlife Science |
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Bibliography Note: |
Includes bibliographical references (pages 111-120). |
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Summary, Etc. Note: |
Summary: This study examined the activity patterns and social relation ships between individuals in a large herd of domestic sheep (Ovis aries) in an effort to determine if behavioral characteristics predisposed certain individuals to coyote (Canis latrans) predation. The research was conducted on the Cook Ranch near Florence, Montana, from March through September of 1975. Data were collected from a herd of 627 ewes and 1082 lambs, each individually identifiable. A random sample of 44 ewes and their 75 lambs were intensively studied over a 16-wk period to establish activity budgets and the relationships between sheep activity and vulnerability to coyote predation. The feasibility of creating target lambs in a free-ranging environment by altering movement, appearance, or social relationships with other herd members was examined in six experiments. During the study, 24 ewes and 47 lambs died from natural causes. Predators killed 7 ewes and 73 lambs. Coyotes selected single lambs, lambs displaying aberrant movement, and lambs whose dams had restricted mobility. Reduced mobility appeared to increase the probability of a lamb being on the periphery of the bedground and this in turn increased the probability of it being encountered by an attacking coyote. Grazing and resting periods of lambs were highly correlated with those of the ewes. Lambs were not within sight of their dams 30 percent of the time and showed a greater tendency to be absent during rest periods than during other activity periods. Yearling ewes investigated less and won less encounters. Brocatelface ewes grazed less and slept more than whiteface ewes. The oldest ewes interacted with other members of the herd less than younger ewes. Although significant differences in behavior existed between different age and genotype cl asses, the behavior of ewes whose lambs were killed by coyotes was remarkably similar to all other ewes. Male lambs were consistently absent from their dams less than female lambs. Single lambs also showed a tendency to be with the ewe more t... |