Seasonal Populations and Movements of the Gray Bat in the Kentucky Area

Abstract

During studies of bat populations of about 100 caves in the Kentucky area, a hibernating colony of about 100,000 gray bats, Myotis grisescens, was found in a cave in Edmonson County, Kentucky. Summe.r colonies were found in 10 caves in Kentucky, Illinois, and Tennessee. Of 3,072 gray bats banded in the winter colony only 12 were recovered in the summer, with one movement of 102 miles. Of 1,622 banded in six summer colonies in Kentucky and Illinois, 153, or 9.4% we-re recovered in the hibernating colony in Edmonson County, Kentucky. These various summer colonies from which bats moved to the one hibernating colony are scattered over an area of about 10,500 square miles of Kentucky, southern Illinois, and northern Tennessee.. The gray bat, Myotis grisescens, has a limited distribution in eastern and southern United States. It has been collected in the following 11 states: Illinois; southern Indiana; Kentucky; Tennessee; Alabama; northern Florida; northern Arkansas; northwestern Oklahoma; Missouri; eastern Kansas; and southwestern Virginia (Hall and Kelson, 1959; Long, 1961; Holsinger, 1964). Most reports of this species concern summer colonies in caves, usually colonies of females rearing their young. Such colonies have been reported in northwestern Arkansas from Benton and Madison Cos. (Black, 1936), northeastern Oklahoma in Adair Co. (Glass, 1955), central Missouri in Boone Co. (Guthrie, 1933), southeastern Tennessee in Marion Co. (Mohr, 1933), and northern Florida in Jackson Co. (Rice, 1955). The sizes of these summer colonies have been reported either as being large or as containing 1,000 to 6,000 individuals. These authors have also noted seasonal movement. The caves that contain summer colonies usually have been found to contain no bats or only a few individuals in winter. A few winter colonies have been reported: Sealander and Young (1955) found M. grisescens in five caves in Arkansas in winter, in Washington Co. (October), Benton Co. (December), Madison Co. (November, December), and Stone Co. (October). Sizes of these colonies are not reported. Bole (1943) reported that a series of M. grisescens was taken from a cave in Grainger Co., Tennessee, on '24 December 1911. Glass (1955) reported the species present in a cave in Adair Co., Oklahoma, in winter. Guthrie (1933) states that only a few are found in the caves of Boone Co., Missouri, in winter. Jennings and Layne (1957) reported 1,200 M. grisescens in a cave in Jackson Co., Florida, in October 1955 and a smaller number in February 1956. Nothing has been published concerning the size of colonies, sea-