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Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)


Wildlife and Fisheries Science

First Advisor

Susan P. Rupp


Elk (Cervus elaphus) are important in the Black Hills of South Dakota because they are a prized game species, but also have negative impacts on private landowners through crop depredation. As a result, elk abundance is essential information required to successfully manage this population. Improvements on traditional population surveys were needed to account for potential visibility bias to gain more reliable estimates of abundance with increased precision. This project resulted in a sightablility model that is calibrated to the conditions specific to the elk population that resides within the Black Hills of South Dakota. Sightability trials of radio collared individuals were conducted during January and February 2009, 2010, and 2011 using a Robinson R-44 helicopter with 2 observers and pilot. We observed 89 of 152 observations of elk groups containing ≥1 radio-collared individual, for an overall sightability rate of 58.6%. Logistic regression was used to model covariates and information-theoretic methods were used for model selection. The best model for estimating sightability included vegetation (%) + group size + snow cover (%). Fit of the best selected model was excellent with an ROC area under the curve value of 0.807. Model selection uncertainty was addressed by averaging parameter estimates across models. Using the averaged Black Hills sightability model to estimate abundance of two harvest units in the Black Hills resulted in an estimate that agreed favorably with an estimate derived from a method that requires marked individuals. Implementation of improved sightability corrected estimation methods will allow for sound management decisions for all stakeholders of elk in the Black Hills but additional evaluation of the model is recommended.

Library of Congress Subject Headings

Elk populations -- Black Hills (S.D. and Wyo.) -- Mathematical models
Aerial surveys in wildlife management


Includes bibliographical references (page 51-58)



Number of Pages



South Dakota State University


Copyright © 2011 Evan C. Phillips. All rights reserved.