  One of the best examples of traditional analysis of evolutionary stable
strategies (ESS) is provided by the so called Dove-Hawk model. In this paper we
present several enhancements to the model aimed at describing the evolution of
cooperative behavior. In addition to Doves and Hawks we introduce several
groups of Cooperators, who act as Doves within their own group, but as Hawks
outside it. This allows to study how cooperating groups may grow and achieve
stability within a nonrepeating evolutionary games framework. Depending on
initial conditions, the final stable population may have one, all-encompassing
Cooperator population or several competing cliques. After taking into account
that Cooperators bear costs necessary to recognize members of one's own group
it is possible to see populations where Cooperators eventually lose against
Hawks or populations where several cliques of Cooperators coexist with a Hawk
population.
