Winter activity patterns of northern flying squirrels in sub-boreal forests

We described autumn-winter activity patterns of northern flying squirrels (Glaucomys sabrinus) in northwestern British Columbia during 1996-1997 and 1997-1998. Nineteen flying squirrels (12 males and 7 females) were fitted with temperature-sensitive radio collars. We located animals in 82 daytime nests using radiotelemetry techniques and monitored 268 nights of activity using data-logging receivers placed at the base of nest trees. The average temperature of the animals, as determined by the collar sensors while the animals were in nests, was 39.2 ± 0.1°C, with no significant differences among animals, tree species, or tree sizes. Activity periods in a mild field season followed a dusk- and dawn-activity pattern, but activities in harsh winter conditions shifted towards a shorter single activity bout or two very short activity bouts in the middle of the night. No long activity bouts (>1.9 h) were observed at temperatures below -20°C. This reduction in time spent active and adjustment of the timing of activity during extremely low temperatures likely serve as an energy-conservation strategy.