David A. Edwards, Jr.
Title of study - Ecological relationships among bobcats, coyotes, and gray foxes in central Mississippi
Date of thesis - May 1996
Little is known about ecological relationships among sympatric bobcats, coyotes, and gray fox. Therefore, 22 bobcats (9 males, 13 females), 19 coyotes (11 males and 8 females), and 8 gray fox (3 males and 5 females) were radio-monitored from July 1993 - July 1995 to investigate movement and activity patterns, home range, habitat use, diet, and interaction on Tallahala Wildlife Management Area, Bienville National Forest, Mississippi. Findings of this study present wildlife managers with a better understanding of how these sympatric predators interact and coexist.
Motion-sensitive transmitters were used to determine activity patterns of predators. Although some statistical differences were detected, activity patterns of these predators were similar throughout the diel period. Predators were most active during crepuscular and night periods. On average, bobcats were more active (57% of locations) than coyotes (51%), and coyotes were more active than gray fox (0.44%).
Movement rates were determined by dividing the straight-line distance by the time interval between consecutive locations. Movement patterns of these predators were similar throughout the diel period with greatest movement rates occurring during crepuscular and night periods, and lowest during mid-day. On average, coyotes moved at a greater rate (0.45 km/hr) than bobcats (0.34 km/hr), and bobcats moved at a greater rate than gray fox (0.20 km/hr). Mean movement rate for all predators was highest during winter. Abiotic factors did not significantly affect predator movement (P > 0.05).
Male bobcat home ranges (674 ha) were larger than female (427 ha). Female coyote home ranges (1,122 ha) were larger than male (744 ha). No differences were observed between male gray fox home ranges (124 ha) and female home ranges (163 ha). Considerable intra- and interspecific home range overlap was observed throughout this study. Habitat use patterns were similar among these predators. Early successional habitats were preferred by all species. However, some habitat partitioning was observed among species.
Mammals, particularly cottonrat, mice, rabbit, and white-tailed deer, were important food items for bobcats and coyotes. However, percentage occurrence of cottonrats and mice was higher in bobcat diets than coyote. Conversely, percentage occurrence of white-tailed deer was higher in coyote diets than bobcat.
No positive dynamic interaction was observed between any sympatric species. Additionally, no dynamic interaction was observed between bobcats. However, positive dynamic interaction was observed among radio-monitored coyotes and gray fox.