During migration, the circannual timing programme instructs birds to become active at night, at the time when wild birds migrate. This actogram shows the activity (black marks) of a hand-raised stonechat in the first spring of its life. Activity is shown over the 24 hour day (plotted twice for better visibility), where each line represents a new day in the year. The bird is normally active in the daytime, but from March, when the wild birds migrate, this captive bird hops and flies in its cage. This night activity, also called Zugunruhe, is used as a measure of migratory inclination.