Thesis - Open Access
Master of Science (MS)
Natural Resource Management
Jonathan A. Jenks
bobcat, cause-specific mortality, lagomorph, population dynamics, South Dakota
Recent concern regarding bobcat (Lynx rufus) population status has prompted researchers and managers to gather additional information about bobcats in South Dakota. From 2012–2015, we assessed population dynamics of bobcats occupying the west-central region of South Dakota. Our objectives were to: 1) estimate annual survival rates; 2) determine cause-specific mortality; 3) estimate a population size for the western prairie region of South Dakota; 4) estimate home range size of individually marked bobcats; 5) evaluate reproductive status; and 6) build a population model. We captured and radio-collared 51 (24 male, 27 female) bobcats with VHF collars. Annual survival was 65.1% (95% CI = 35.9–86.2%) in 2013–2014, 75.9% (95% CI = 57.4–88.0%) in 2014–2015, and 71.5% (95% CI = 47.2–87.6%; 2015 September–2016 March) in 2015– 2016. Monthly survival during December–February was 90.4% (95% CI = 85.3–93.9%), whereas survival during remaining months was 99.4% (95% CI = 97.7–99.9%). Human caused mortality was most common (n = 10), followed by infection (n = 2), and interaction with other bobcats (n = 2). Harvest rates were 28.6% (8.2–64.1%; 95% CI), 14.3 % (5.7–31.5%; 95% CI), and 8.8% (3.0–23.0%; 95% CI) for 2013, 2014, and 2015, respectively. Population estimates for 2013, 2014, and 2015 were calculated using bobcats ≥1 year of age; population size for western South Dakota (excluding Black Hills) for 2013–2015 was 450 (113–788, 95% CI), 839 (279–1400, 95% CI), and 1315 (296–2329, 95% CI), respectively. Overall 95% fixed kernel home range for adult females and males averaged 23.4 km2 (SE = 4.9) and 80.0 km2 (SE = 12.2), respectively. Additionally, juvenile bobcat 95% fixed kernel home range averaged 72.3 km2 (SE = 18.9). Male home range size was statistically larger than females (P < 0.001). Bobcats that produced a litter averaged 2.7 kittens/female. We noted a significant difference between the average number of placental scars by year (P < 0.001); mean number of placental scars for the 2012–2013 harvest season was statistically higher (P < 0.001;) than the 2013–2014 harvest season. The highest documented statewide pregnancy rate during the project occurred in 2014 (59.4%), whereas the lowest occurred in 2013 (46.9%). There was a difference (P < 0.001) among means in the Kidney Fat Index over the 3-year study; the 2014-2015 harvest season produced the lowest Kidney Fat Index compared to the 2012-2013 (P < 0.001) and 2013–2014 (P = 0.006) harvest seasons. Annually, lagomorphs comprised the largest percent frequency of stomach contents, except for lands east of the Missouri River during the 2014–2015 harvest season (small mammal and ungulate). Our confidence intervals overlap for our population estimates potentially indicating no annual increase in bobcat numbers; however, observed high survival rates and increasing reproductive output suggest the population has the potential to increase in our study area.
Library of Congress Subject Headings
Bobcat -- South Dakota
Bobcat -- Mortality -- South Dakota
Bobcat -- Home range -- South Dakota
Bobcat -- South Dakota – Reproduction
Includes bibliographical references (page 78-82)
Number of Pages
South Dakota State University
Copyright © 2016 Brandon M. Tycz
Tycz, Brandon M., "Evaluation of Bobcat (Lynx rufus) Survival, Harvest, and Population Size in the West-Central Region of South Dakota" (2016). Electronic Theses and Dissertations. 988.