Nodding: an Appeasement Behaviour of Pigeons (Columba Livia)

A variety of displays performed by social animals in agonistic encounters are termed "appeasement behaviours", although experimental proof of the appeasing effect is rare. In pigeons, nodding occurs in both sexes during courtship and pair formation, often in response to an aggressive act of the mate. Tame domestic pigeons (Columba livia) which courted and attacked the human hand, were used to test the effect of imitations of nodding versus two alternative stimuli: the hand held still in front of the bird or waved horizontally. In all six birds (two males and four females) presentation of the nodding hand had two effects: (1) It instantaneously reduced or stopped aggressive pecking (inhibition), and (2) it stimulated-faster than the other stimuli-the occurrence of nest demonstration, a squatting attitude characterizing a non-aggressive state (appeasement). Low correlation between peck rate and time until nest demonstration (latency) suggested that inhibition and appeasement arc based on different motivational processes. The significant decrease of both peck rate and latency over the 20 day testing period probably reflected habituation to the mate's presence. The combined information from this and other studies suggests that short- and long-term processes are both involved in the development of non-aggressive long-term relationships between aggressive conspecifics.