Graduate Program
Biological Sciences
Degree Name
Master of Science (MS)
Semester of Degree Completion
2007
Thesis Director
Thomas Nelson
Thesis Committee Member
Paul Switzer
Thesis Committee Member
James Novak
Abstract
The North American red squirrel (Tamiasciurus hudsonicus) is a species of special concern in Illinois due to its restricted geographic range and low numbers. This species occupies a broad geographic range in North America and is usually associated with the boreal forests of Canada and coniferous forests in the Rocky Mountain range. The squirrels also occupy deciduous and mixed deciduous-coniferous forests in the eastern U.S. In Illinois, available habitat is suboptimal, and limited to pine plantations and small tracts of deciduous forest embedded in an agricultural matrix landscapе. Information on the spatial distribution of red squirrels in northeastern Illinois was lacking until this study. In addition, little research had quantified resource selection of red squirrels in these habitat types. My study was designed to investigate and quantify summer habitat use of red squirrels at multiple spatial scales, ultimately contributing to the successful management of this population. The main research objectives for my study were to: (1) determine habitat use and preferences of Illinois red squirrels, and (2) delineate the current distribution of this species in the state.
Trapping and radiotelemetry occurred from May-August 2006 and 2007 at Iroquois County State Wildlife Area in northeastern Illinois. Home ranges were calculated and habitat preferences determined for 38 individual squirrels. The size of home ranges for all squirrels averaged 1.7 ha (SE = 0.24) and mean core area size was 0.4 ha (SE = 0.06). A X² goodness-of-fit test and compositional analysis were performed at both the 2nd_ and 3rd-order selection levels. Results indicate that within the study site, deciduous forest was preferred and within home ranges, pines were used frequently. Key habitat components appear to be mast-producing walnut or pine trees, a dense understory, snags, and downed wood. Red squirrels in this region did not exhibit territorial behavior and scatterhoarded their food items. These animals also spent considerable time on the ground foraging in thickets and dense understory.
To better delineate the current geographic range of red squirrels in Illinois, I conducted extensive phone and email interviews, posted public notices, and conducted acoustic point count (playback) surveys. My research suggests that Illinois red squirrels have a broader distribution than previously documented. In addition to inhabiting large tracts of deciduous forest, red squirrels were also found in small, isolated patches surrounded by grassland and agricultural fields. Results indicate that on a regional scale, highways, rivers, cities, cropfields, and grasslands are not barriers to the dispersal of red squirrels. Primary movement corridors appear to be along the Kankakee and Iroquois rivers and their tributaries.
Recommended Citation
Hanson, Corinna, "Red Squirrel Distribution And Habitat Use In Illinois" (2007). Masters Theses. 37.
https://thekeep.eiu.edu/theses/37
