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. Received 9 July 2002. accepted 24 March 2004.
We describe an extraordinary form of agonistic interaction between broodmates of the Crested Ibis (Nipponia nippon), a critically endangered ciconiiform (Liu 1981). Aggression among altricial broodmates occurs in a variety [...]