In December of each year, flocks of up to 20 Black Oystercatchers return to Race Rocks, having been away since the end of summer. They spend hours in their flocks on the South side of Great Race Rock. If one observes them for awhile they will note some interesting patterns of behaviour: sleep, preening, and alert behaviour when there is a possible danger nearby. This clip can be used as a short version sample for the lab on ethology.