Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Wildland Resources

Department name when degree awarded

Wildlife Resources

Committee Chair(s)

David F. Balph


David F. Balph


A marked population of Spermophilus armatus averaging 529 individuals per year was studied for two and a half seasons on a 22-acre tract in northern Utah. The average date of emergence from hibernation of the first squirrel was 9 April. Mating occurred as soon as animals emerged from hibernation. The average date of appearance of the first litter was 31 May. Emergence sizes of litters were from 5.2 for yearling females to 6.3 for adult females. Few instances of predation were observed. Age and sex ratios varied throughout the season and for different portions of the study area. The population increased 22 percent from 1964-1965 and 15 percent from 1965-1966. Juveniles moved more than adults and males moved more than females. In 1964 and 1965, 90 percent of the squirrels had disappeared into hibernation by 1 August. Active periods were from 61 days for juvenile males to 97 days for adult males.