Home Range and Activity of a Gray Squirrel Population

Abstract

Home range determinations were made on observation-trapping, trapping, and radiotracking locations for 55 gray squirrels (Sciurus carolinensis). The mean minimum home range for all data was 0.49 ha (1.20 acres); the greatest linear dimension was 136.7 m (448.6 feet). Males had a larger home range than females. Radiotracking produced smaller mean home ranges and greater linear dimension measurements than did observation-trapping. Composite home ranges assumed an elipse shape skewed along the major axis. The 11 environmental variables tested contributed little to describing the variance in squirrel activity; no determination between active and inactive groups was attained using a discriminant function analysis. J. WILDL. MANAGE. 38(4):860-867 Once a better understanding of animal movements has been attained, such problems as predator and disease control, food and cover production and manipulation, censusing, and movements beyond management areas may be approached more intelligently. This study was conducted to determine the size and shape of gray squirrel home ranges within a population; also analyzed were the effects of various environmental factors on squirrel winter activity. Home ranges determined by trapping and direct observation were compared with ranges determined by telemetry and trapping on the same site one year apart. The availability and adaptability of the gray squirrel made it an excellent subject for movement investigations. Many data concerning home range of the gray squirrel have been collected incidental to larger studies (Seton 1928, Goodrum 1940, Brown and Yeager 1945, Allen 1952, Moran 1953, Uhlig 1955). On the present study area, Pack (1966) determined an average home range of 0.50 ha (1.24 acres) and 0.59 ha (1.45 acres), depending on the sample on which the calculation was based. Flyger (1960), working in two Maryland woodlots which were comparable to the present study area, calculated an average home range of 0.57 ha (1.40 acres). Little can be found in the literature concer ing the consistent response of gray squi rels to various weather conditions. Hicks (1949) reported on fox squirrel (Sciurus niger) activity, but no statistical analysis was attempted. Most of the information on gray squirrel activity has been obtained by casual observation. The most consistent factors affecting activity which have been reported are low temperatures when accompanied by high winds (Bakken 1959, Sharp 1959, Pack 1966). This combination tended to reduce squirrel activity. Use of the data from the thesis of J. C. Pack is gratefully acknowledged. Special thanks are extended to H. S. Mosby and H. E. Burkhart for review and criticism of the