Sex Ratios and Population Density in Hibernating Myotis

Abstract

This study was undertaken as a part of an investigation of the biology, parasites and migration of bats of northwestern Texas supported by the National Institute of Health through a grant to Dr. Russell W. Strandtmann of Texas Technological College. We wish to acknowledge the help of many Texas Technological College faculty and students, but we are particularly indebted to Russell Strandtmann, Jessie Hillman, Colene Amondson, Chester Rowell and John E. George. We wish to thank Messrs. J. A. Hedgecoke of Amarillo, R. W. Walkup of Lazare and F. L. Richardson of Quanah for permission to study caves located on their ranches. The data reported here were obtained in 1958 and 1959 in three gypsum caverns located in Armstrong, Cottle and Hardeman Counties in the Texas Panhandle. These caves lie within the mesquite plains and short grass plains of the Kansas biotic province (Blair, 1954). The major objectives of the investigation were to estimate population density in bats by mark and recapture techniques and to study sex ratios to determine if they fitted the general pattern suggested by previous authors. A total of 3288 Myotis velifer incautus were banded during the course of this study, most of them at three caves. Exact locality data on these and other distributional records have been reported (Milstead and Tinkle, 1959).