Evaluation of Methodology Use to Estimate Population Size, Sex and Age Ratios, and Mortality of White-tailed and Mule Deer in the Missouri River Breaks Region of South Dakota

Methods used to estimate population size, sex and age ratios, and mortality of white-tailed (Odocoileus virginianus) and mule deer (0. hemionus) were evaluated on the= Lower Brule Sioux Reservation, South Dakota. Thirty-three white-tailed and 19 mule deer were radio-collared from 1997-1999 to assess visibility factors associated with winter aerial deer surveys. Radiotelemetry was used to determine if radio-collared deer were observed during aerial surveys. One hundred three radio-collared deer were observed during aerial surveys from 1998-2000. Stepwise logistic regression indicated that sightability was influenced by deer group size (e < 0.046) and deer behavior (.e <0.001). The independent variables percent snow cover (f=0.698), percent tree cover (e = 0.308), topography (f = 0.831), deer species (f = 0.882), and survey area (e = 0.801) did not influence the probability of observing deer. A model containing group size and deer behavior to predict the sightability of deer was developed. The linear regression portion of the model was: y = -2.055 +Group Size (0.211) - Behavior (2.869). Dusk and dawn surveys were conducted to compare fawn:doe and buck:doe ratios estimated from spotlight surveys. Number of deer observed during spotlight and dusk/dawn surveys were different for white-tailed deer (P= 0.025) and all deer combined (P=0.018); the number of mule deer observed differed at£= 0.058 between spotlight and dusk/dawn surveys. The percentage of males, females, and fawns observed during spotlight and dusk/dawn surveys did not differ for white-tailed deer (P= 0.857) or mule deer (P= 0.255); percentages differed for total deer at e = 0.092. Thirty-nine structures that resembled deer eyeshine were placed randomly along spotlight survey routes to estimate the probability of seeing deer within the survey area. Observers were unaware of the location and number of these structures. Observers saw 88% of the reflectors. Mean summer and winter 95% adaptive kernel home ranges were determined for 13 female and 5 male mule deer and 17 female and 7 male white-tailed deer. Summer home ranges were larger than winter home ranges for mule deer, whereas winter home ranges were larger than summer home ranges for white-tailed deer. Summer home ranges for male and female mule deer averaged 1,212 ± 146 and 624 ± 74 ha, respectively. Winter home ranges for male and female mule deer averaged 428 ± 207 and 431 ± 81 ha, respectively. Summer home ranges for male and female white-tailed deer averaged 603 ± 131 and 330 ± 74 ha, respectively. Winter home ranges for male and female white-tailed deer averaged 1, 118 ± 131 and 616 ± 73 ha, respectively. Natural mortality was the only cause of mortality for female white-tailed and female mule deer. Natural mortality (67%) was the primary cause of mortality for male white-tailed deer, followed by accidental causes (33%). Harvest mortality was the only cause of mortality of male mule deer. Survival rates for all deer by year were 0.7380 ± 0.0071 in 1997, 0.8485 ± 0.0033 in 1998, and 0.9371 ± 0.0020 in 1999; which differed (P< 0.0001) across years.

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Thesis - University Access Only

Discipline thesis:degree_discipline

Wildlife and Fisheries Science

Year

2000

Author dc:creator

• Grassel, Shaun M.

Contributors dc:contributor

• Jonathan A. Jenks

• south dakota
• white-tailed deer
• mule deer
• missouri river region
• mortality
• population
• Natural Resources and Conservation

Statement dc:rights

• Copyright © 2000 Shaun M. Grassel. All rights reserved.

Language dc:language

en

Repository record dc:identifier

https://openprairie.sdstate.edu/etd/440

OAI identifier oai:identifier

oai:openprairie.sdstate.edu:etd-1440