Survival and Movements of Banded Big Brown Bats

Abstract

Between 1932 and 1951, over 67,000 bats have been banded in North America (Mohr, 1952). This gives some idea as to the lack of data for any given species since there are some 36 species of bats found in the United States. The number of big brown bats banded has not been large. The literature based on these banding data contains some instructive information as well as some controversial points. Griffin (1940a) came to the conclusion that big brown bats winter relatively close to their summer quarters while Rysgaard (1942) was of the opinion that they traveled many miles between winter and summer quarters. The greatest distance recorded between summering and wintering localities by Griffin was ten miles while Rysgaard reasoned that since few big brown bats were collected near the wintering quarters in the summer and a few were collected at long distances from known suitable wintering places, they must normally make quite long migrations. Reynolds (1942) recorded one adult female wintering 3.5 miles from the summer roost and Hitchcock (1949) reported two big brown bats banded in winter as being reported at 16 miles and “within a few miles” of the point of banding. Hitchcock also reported that three bats banded in the summer were subsequently recovered in buildings during the winter—all within five miles of the point of banding. All workers will agree with Hitchcock's (1949) statement: “the number of banded bats recaptured away from their places of hibernation has been disappointingly small.” This study of the survival and movements of big brown bats, Eptesicus fuscus (Beauvois), began during the winter of 1940–41 when G. N. Rysgaard and W. H. Elder started banding cave bats in Minnesota and Wisconsin, respectively. Rysgaard examined all of the caves then known in Minnesota and during his one winter's work banded …