Phylogenetical Constraints in the Evolution of Parental Care Strategies in Birds

In species with internal fertilization, but without parental care, an evolution of "maternal care" is fundamentally different from an evolution of "parental care". Maternal care should be a pure EES. Paternal care should always be superimposed on a mixed ESS to stay (or not to stay) and to establish some kind of a pair-bond with the female from copulation until egg-laying. This implies that paternal care is less reliable than maternal care. This could have led to the evolution of female strategies and properties which raise the chances for male care. The above considerations offer a framework for the evolutionary pathways between the various parental care strategies and between their associated mating systems. It is advocated that the evolution of parental care in birds was primarily based on a monogamous care systems.