Chapter 14: Aggression
Broodmate Aggression
Video by Hugh Drummond
Success or failure in aggressive encounters often has profound effects on an individual’s performance in subsequent interactions with conspecifics, and such effects are termed winner versus loser effects. Here, a second-hatched blue-footed booby (Sula nebouxii) chick (head painted yellow) threatens and ultimately attacks the third-hatched chick (head painted blue) while the first-hatched chick (head painted red) rests. Hatching asynchrony in birds promotes siblicide, and latter-hatched chicks often behave as losers, responding regularly to aggression with submissive behavior, such as the bill-down and face-away posture of the third-hatched chick in this video clip. While the third-hatched chick is rendered a loser, the experience of dominating its younger sibling does not promote the appearance of a winner effect in the second-hatched chick, exemplifying the asymmetrical expression of winner and loser effects in certain species.
See Chapter 4 -- Learning, Chapter 14 – Aggression.
Further reading – Benavides, T. & Drummond, H. (2007). The role of trained winning in a broodmate dominance hierarchy. Behaviour 144: 1133-1146.