Discriminating by Tagging: Artificial Distinction, Real Discrimination

We introduce a new variation of the hawk-dove game suggested by an experiment that studies the behavior of a group of domestic fowls when a subgroup has been marked. Speci cally we consider a population formed by two types of individual that fail to recog- nize their own type but do recognize the other type. In this game we find two evolutionarily stable strategies. In each of them, individuals from one type are always attacked more, whatever proportion of the population they represent. Our theoretical results are consistent with the conclusions drawn from experimental work, where marked fowls received more pecks than their unmarked counterparts.