Age, Sex, Reproductive Characteristics and Harvest of Wisconsin Red Fox

Abstract

A sample of 203 red fox (Vulpes vulpes) were collected from three ecologically distinct areas of Wisconsin during 1972-73. The sex ratio of the statewide sample is 55 percent males to 45 percent females. Sex ratios (male:female) for the Northern, Southern and Western study areas are 56:44, 54:46 and 56:44 respectively. Mean potential litter size, calculated by counting placental scars and uterine swellings, is 4.5. Comparison between placental scars and uterine swellings indicate a possible 24 percent loss due to interuterine mortality. Mean age of the sample, obtained by cross sectioning the fourth premolar, is 1.6 years with a range of 6 months to 8 years. More foxes were trapped than shot, with a significant difference in age of animals shot. A time-specific life table was constructed which indicates mortality follows a "U" shaped trend with an average expected life span of 1.6 years. The calculated replacement rate of r=0.56 indicates that the population is replacing itself and increasing.