In an attempt to describe, explain, and show the demographic significance of annual variations in the nesting distribution of Uinta ground squirrels, a study was conducted during the summers of 1964 through 1967 in northern Utah. Procedures included both trapping and direct observation. It was found that females tended to nest in open, previously inhabited, grassy areas. Males resided throughout a variety of habitats. This typical nesting distribution was established initially in the summer by juveniles shortly after they first appeared aboveground. The extent to which the distribution was maintained the following spring depended largely upon the number of female s which emerged from hibernation and the pattern in which they emerged. The number of females which appeared depended upon the previous year's breeding density and productivity. The pattern of emergence appeared to be a function of an inherent pattern of physiological arousal from hibernation and the prevailing weather conditions. The number and sequence of emergence of females in the early spring affected breeding and social organization in a manner which limited the number of females which retained residences in the study area. This determined the actual breeding density. In addition, emergence influenced the production of offspring by altering both the breeding density and the number of non-productive females in the population. The adaptive significance of the system and its applicability to other species are discussed.

The annual demography of a population of antelope ground squirrels in Curlew Valley, Utah was studied by measuring population density, natality, and mortality. Capture- recapture techniques yielded lower estimates than the Hayne strip- census. The estimates suggested 1968 was a year of population decline. One hundred seventy- three squirrels were collected and autopsied to obtain sex ratio , age structure, natality, and mortality data . The seasonal sex ratios for adult and yearling squirrels showed 82 percent females in spring 1968, this gradually changed to 56 percent by winter . The seasonal sex ratios of the young squirrels showed 59 percent females upon emergence from natal burrows in summer 1968, increasing to 79 percent by winter. The squirrels collected were aged by cementum annuli . The oldest were believed to be 5 years old . They composed 1.2 percent of the collection while young- of- the-year composed 38. 7 percent. The estimate of mean corpora lutea was 7.6, the mean embryo count was 7.2, and the mean post-partum placental scar count was 5.8. The mean corpora lutea count for yearlings was statistically lower than the count for adults and the mean ovulation rate for 1968 statistically lower than the rate for 1969. An estimate of litter size from four nests gave a mean of 4.5. In 1968, the conception rate was 91 percent with yearlings comprising 75 percent of those not conceiving. In 1969, the rate was 100 percent. Pre-Emergence mortality of the young was 41 percent. post-emergence mortality was 86 percent, and mortality, March - November, 1968 was 92 percent. Adult and yearling spring-to-spring mortality for study area squirrels calculated from retrap data was 81 percent. Spring-to-spring mortality calulated from age distribution data and Ricker's formula was 71 percent. The spring-to-fall mortality for 1968 calculated from density estimates and age distribution data was 53 percent.

Sound attenuation properties of the habitats occupied by two species of tree squirrels affect whether or not the squirrels will make alarm calls. Sound properties have been compared among habitats, microhabitats, weather conditions and seasons. In each case alarm calling activity is consistent with the hypothesis that calling behavior is acted upon by natural selection: calling occurs when squirrel calls carry well, and thus where the potential for communication is high.

No description available.

Thesis (Ph. D.)--Carleton University, 2002. / Includes bibliographical references (p. 166-178). Also available in electronic format on the Internet.

Thesis (M. Sc.)--Carleton University, 2004. / Includes bibliographical references (p. 119-132). Also available in electronic format on the Internet.

Thesis (M.Sc.) - Carleton University, 2005. / Includes bibliographical references (p. 134-145). Also available in electronic format on the Internet.

Thesis (Ph.D.) - Carleton University, 2006. / Includes bibliographical references (p. 118-138). Also available in electronic format on the Internet.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1959. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 148-162).

Thesis (M. Sc.)--Acadia University, 1997. / Includes bibliographical references. Also available on the Internet via the World Wide Web.