Brood parasitism and the evolution of cooperative breeding in birds: Part 1

Cooperatively breeding passerines are targeted by parasitic species more frequently and due to their heavy cost, defense mechanisms in the form of mobbing have also evolved in response to this.  Feeny and his team initially began their study due to the overlapping concentrations of cooperatively breeding passerine species and parasitic species in australian and african regions.Furthermore, the driving force between these interactions is unclear and they note that this may be a coincidence secondary to the unpredictable environments they both inhabit. They proposed that 3 non mutually exclusive theories that could have driven the evolution of this behavior: 1. The parasitic offspring receive the greatest care, cooperative nests are more easily visible due to their activity and finally cooperative breeding may be selected for as they can better defend their nests from parasites.