The flight season of Sympetrum striolatum in NW Germany extends into the beginning of winter. To understand behavioural thermoregulation we studied the body posture of females and males on cool (T_a <10°C) and overcast days. Although this species typically roosts in treetops, we discovered a few individuals perching on birch stems or roosting low on birch twigs. In both situations the wings were held predominantly horizontal relative to the dragonfly's body, the legs were moderately stretched and the body axis was positioned parallel to but distant from the support. When the surface temperature of the bark was cooler than the ambient air, the individuals changed their perching angle to maximize the distance of pterothorax and abdomen from the support.