Sex Ratios and Seasonal Movements of Gray Bats (Myotis grisescens) in Southwestern Missouri and Adjacent States

Abstract

Banding of 18,768 gray bats (Myotis grisescens) in a hibernaculum in SW Missouri has demonstrated considerable movement to and from this major wintering cave. Bats moved out as far as 640 km, but most were found within a radius of 200 km as shown by 199 recaptures. Of 4700 bats we banded at 11 summer nursery colonies in Missouri, Oklahoma, Kansas and Arkansas, 110 bats from only four of the caves were later found at Marvel Cave. We found an additional 201 banded bats at Marvel Cave that had been banded by other investigators in 10 other nursery colonies. Marvel Cave serves as a hibernaculum for bats from an area ca. 126,000 km2. Half of the 25 bats captured two or more summers were faithful to the same summer cave. Some bats wintered in other hibernacula up to 175 km distant from where banded at Marvel Cave. Most summer colonies were predominantly female; by October some colonies were strictly male. Sex ratios at Marvel Cave varied from 23 51% male and seemingly were influenced by month and technique of collecting.