A wide variety of displays are seen, with aggressive behaviours outnumbering pro-social ones. Crouching low and uttering quiet begging calls are common signs of submission. The "manus flutter" is a submissive display where a magpie will flutter the primary feathers in its wings. A magpie, particularly a juvenile, may also fall, roll over on its back and expose its underparts. Birds may fluff up their flank feathers as an aggressive display or preceding an attack. Young birds display various forms of play behaviour, either by themselves or in groups, with older birds often initiating the proceedings with juveniles. These may involve picking up, manipulating or tugging at various objects such as sticks, rocks or bits of wire, and handing them to other birds. A bird may pick up a feather or leaf and flying off with it, with other birds pursuing and attempting to bring down the leader by latching onto its tail feathers. Birds may jump on each other and even engage in mock fighting. Play may even take place with other species such as blue-faced honeyeaters and Australasian pipits.