We present a model of two interacting populations using two individual stra
tegies, hawk and dove. Individuals encounter each other frequently and can
change tactics several times in their life. Conflicts occur between individ
uals belonging to the same population and to different populations. The gen
eral model is based on the replicator equations which are used to describe
the variations of the hawk proportions of the two populations. According to
parameter values, namely the gain-, the intra- and inter-population costs,
and the relative intra-population encounter rates, we classify the differe
nt phase portraits. We show that a decrease in the intra-population cost of
a population provokes an increase in the hawk proportion in this populatio
n and of the dove proportion in the other population. An increase in the in
ter-population cost favors hawk strategy in the population which causes mor
e injuries and dove strategy in the other. We also study the effects of the
relative densities of the two populations on,the stability of equilibria.
In most cases, an increase in the relative density of a population leads to
a decrease in hawk proportion in this population and of dove proportion in
the other.