Behavioural Ecology and Evolutionary Genetics
Every individual of a species is unique. Individual variation can be discovered in morphology (for example in body size, in plumage and beak colour), but also in behaviour such as mate choice strategies or competitive behaviour. What are the causes of this variation in natural populations and what maintains the variation? What is the role of sexual selection? Which information is contained in the variation? How important is individual recognition? Our research focuses on the evolution of mate choice and sexual ornaments in birds. Which criteria do individuals use to select a short- or long-term partner? Why do birds divorce and why do they engage in copulations with multiple partners? Which signals are used in mate choice? Do they reflect individual quality? What are the costs for an individual to develop such signals? What is the importance of individual genetic diversity (heterozygosity-fitness correlations)? To answer these questions, we study birds in their natural habitat, as well as in captivity. We use a combination of behavioural observations and molecular methods, including microsatellite analysis and a candidate gene approach. Our main study is on blue tits (Cyanistes caeruleus), a small songbird that breeds in nestboxes and remains resident in winter. Our study area is a protected oak-rich forest in Bavaria. For the next decades, we plan to monitor the life-history of all individuals in the population, using advances in transponder technology. We also work with a variety of other species, including house sparrows, red queleas and zebra finches. In the tundra near Barrow (Alaska), we work on mating strategies of two shorebirds: the monogamous semipalmated sandpiper (Calidris pusilla) and the polygynous pectoral sandpiper (Calidris melanotos).