RITUALIZED AGGRESSION AND UNSTABLE DOMINANCE IN BROODS OF CRESTED IBIS (NIPPONIA NIPPON)

In broods of Crested Ibis (Nipponia nippon), aggressive dominance was unstable over time, even within feeding sessions. All chicks took turns pecking aggressively while broodmates hung their heads submissively, although roles were contested at the start of feeding bouts when chicks were 11-17 days old. In all broods, at least half of all pecks were false pecks, which did not strike broodmates even when within reach. False pecks seem to be ritualized displays that function to solicit food from parents and possibly to threaten rivals.