| In temperate-zone mammals, decisions about energy allocation are often governed by seasonal changes in weather and food availability. In addition, energy allocation strategies usually differ between males and females. The study of energy allocation is challenging for bats, especially those that do not roost in areas known or accessible to humans. We evaluated year-round changes in body condition for three species of bats in northern California: silver-haired bat (Lasionycteris noctivagans), California myotis (Myotis californicus), and Yuma myotis (Myotis yumanensis). The two species of myotis are considered resident species that do not migrate. Silver-haired bats are considered migratory species, with females likely migrating farther than males. Body mass of all species peaked in late autumn and were at a minimum during spring. There were significant differences in body mass between sexes and among seasons in all three species. We used sex- and season-specific multiple linear regression models of change in body condition to quantify these changes. Interspecific comparisons provided valuable insights into the energy allocation and overwintering strategies of these species and are important first steps toward understanding their ecology over the full annual cycle. |