THE EVOLUTION OF FAMILY LIVING AND COOPERATIVE BREEDING IN BIRDS

Cooperative behaviour among individuals stands in contradiction with the traditional view of natural selection, which states that individuals should behave selfishly. While research the past 60 years has greatly improved our understanding of cooperation, research has not paid sufficient attention to factors which promote social group formation, but rather researched the factors which promote social group maintenance. In birds, a key group used to study the evolution of cooperative breeding, theories and comparative analyses so far came to contrasting conclusions regarding the role of ecological and life-history factors which facilitate the evolution of cooperative breeding. However, all studies so far contrasted cooperative breeders with all other species, which is an erroneous approach. We could show that social evolution in birds is a step-wise sequential process between pair living, family living and cooperative families. I discuss which factors might promote family living, and elucidate what this means for our understanding of cooperative breeding.

Michael’s research tries to understand why family living in birds evolves, and how individuals interact with each other in groups. Using large sets of European bird species, and in collaboration with numerous researchers worldwide, Michael focuses on the link between life-history, ecological factors and family living. The detailed behavioural mechanisms of family living are addressed in Siberian Jays, while we use Brown Thornbills to understand the links between nest-predation and social decisions. Michael specifically researches the influence of individual quality on reproductive investment and the life-history consequences thereof using Siberian Jays, as well as Great Tits. For a more general understanding of group-living, Michael and colleagues look at the mathematical and behavioural processes of grouping decisions in House Sparrows.

Image credits: PedrMichael Griesser