The Swamp Rabbit (Sylvilagus aquaticus) in Indiana

Abstract

Swamp-rabbit (Sylvilagus aquaticus) distribution, habitat, population characters and behavioral traits were studied in Indiana in 1968-69. Swamp rabbits were found in 25 swampy forested tracts in the six most southwestern counties. All sites were within the Southern Swamp Forest type, with the most northern site about 18 km S of Vincennes. The most frequently used winter foods were cross vine (Bignonia capreolata), sedges (Carex spp.) and poison ivy (Rhus radicans). Body characters of swamp rabbits from Indiana, Illinois, Missouri and Georgia probably follow Bergmann's Rule, but the data are not conclusive. Approximately 4050 ha of habitat remain from a presettlement area of 40,500 ha. The state population estimate was 1,000, with a probable annual successful natality of 50-55%, and an annual hunter kill of 40-45%. The mean home range on Cane Ridge was 4.4 ha, with a population density of one rabbit per 2.4 ha. Permanent nonrandom log transects can probablv be used to (1) estimate hunter kill in per cent of the population, ( 2) reveal long-term population trends, and (3) when combined with hunter rabbit-kill data, to calculate the rabbit density. INTRODUCTION The first positively identified swamp rabbits (Syivilagus aquaticus) from Indiana were reported in 1930 when four were shot in the canebrakes in Point Township, Posev Co. (Harrison and Hickie, 1931). Lyon (1936) published records for Posey and Warrick counties. In 1959, Kirkpatrick (1961) collected a swamp rabbit from Spencer Co. Specimens were obtained by T. Tichenor in the Broad Pond Swamp in Gibson Co. in 1966. In 1967, a cooperative program was established between Purdue University's Department of Forestry and Conservation and the Indiana Division of Fish and Game to determine the status of the swamp rabbit in Indiana. The objectives, of the study were: (1) to delineate the distribution of the swamp rabbit in Indiana, (2) to obtain population data and (3) to gain a more complete ecological perspective of the species.