U.S. Department of Agriculture: Animal and Plant Health Inspection Service


Date of this Version

May 1983


Published by JOURNAL OF MAMMALOGY Vol. 64, No. 2.


A 13-year study of an isolated red squirrel (Tamiasciurus hudsonicus) population in Montana has provided the data necessary to analyze their survival. Such long-term, intensive studies of wild populations are rare. When reported, derived (ratio) estimates are used to develop survival information as Gross et al. (1974), and Keith and Windberg (1978) did in respective 9- and 15-year lagomorph studies. A more accurate method, following cohorts, was used by Armitage and Downhower (1974) and Mosby (1969), who presented results for six or more year-classes of sciurids in actuarial tables (Deevey, 1947; Allee et al., 1949).