Tinkerbirds are tiny tropical African birds that sing very simple songs. Genetic variation is thought to parallel song variation among populations of birds that do not learn their songs culturally, such as tinkerbirds. The aim of this project is to examine the genetic basis of a pattern of divergence in song between populations of two related species, as well as divergence in body size and beak shape. Such divergence is predicted to occur in order to facilitate coexistence of two species that are so similar in ecology and behavior that individuals of each species could compete with each other as they would with individuals of their own species. If two species fail to recognize each other as different species, they could even mate with each other and produce infertile hybrids. The process of divergence in ecological or behavioral traits that facilitates recognition and coexistence of related species is known as character displacement. Analyses will also account for the possibility that song, body size, and beak shape are adapted to differences in the environment, or vary randomly over geographic distances.
While character displacement is a well-established theory in ecology and evolution, few examples have been found in nature. This study will provide the first unambiguous demonstration of character displacement in bird song, and provide support for it with parallel shifts in body size and beak shape. The project involves working with conservation organizations in Uganda and Cameroon, employing their staff as well as Ugandan university undergraduates as field assistants, thus helping the development of scientists in developing countries.
