Average percent decline in little brown bat body condition index (BCI; mass/forearm length) and rate of mass loss between swarming (15–19 Sept 2009), early hibernation (28, 29 Nov 2009) and late hibernation (27, 28 April 2010).

*Duration of hibernation season in Ontario (Fenton, 1970). This value has been used by other several other studies of winter energy budgets, although it may be shorter than the duration of hibernation for individuals from our more northerly study site.