Gretchen Wagner

I am interested in the evolution and ecology of social systems. For my PhD studies I am investigating the evolution of delayed dispersal in birds, particularly how ecology and life-history traits contribute to the formation of family groups. My research is based on comparative studies and field experiments with several species of birds to determine how family formation strategies (young delay dispersal past independence, parents prolong investment in young) have evolved in some species, while other species promptly disperse and parental investment ceases after reaching independence. By using a comparative method, I hope to determine what ecological pressures as well as life-history traits contribute to the formation of these different social strategies, and why delayed dispersal may be an optimal strategy for some species while prompt dispersal may be optimal for others.

Past research has largely focused on evolutionary differences between cooperative breeding birds and non-cooperative breeding birds, while little attention has been paid to those in which juveniles stay with their parents beyond independence but do not actually help with breeding. I believe this distinction is an important one, as the costs and benefits of cooperative breeding differ from the costs and benefits of remaining with parents without helping to raise subsequent broods. Similarly, the costs and benefits of prompt dispersal differ from the costs and benefits of delayed dispersal. Therefore species that exhibit family living without cooperative breeding should not be clumped together with those of either of the other strategies, as it is clear that there are evolutionary differences between these systems and this seemingly intermediate strategy should not be ignored.

Other research that I have been involved with includes investigating several facets of social behavior in cetaceans (under the supervision of Dr. Michael Noonan, Canisius College, New York), exploration of the ecology (with M Noonan) and cognition (under the supervision of Dr. Diana Reiss, CUNY Hunter College, New York) of Asian elephants, as well as studying patterns of brown-headed cowbird brood parasitism on eastern phoebes (under the supervision of Dr. Mark Hauber, CUNY Hunter College, New York).