We work on sexual selection, with special emphasis on sperm competition and evolution, mating systems and the evolution of ornaments and plumage coloration in birds. The study of sexual selection has come a long way since Charles Darwin defined it in 1871, but recent advances in molecular techniques, portable spectroradiometry, and instruments for measuring sperm behaviour, as well as some exciting theory make this a vibrant field of scientific enquiry today.

See PUBLICATIONS page for full list of publications.

Bird plumage colours How do colours reflect the phenotypic and genetic quality of individuals? We ask how colours are related to social interactions, reproductive success, mate choice and parental care.

Sperm Competition and sperm evolution We have been studying the structure and behaviour of sperm from birds, fishes, snakes, and frogs to see if intense sperm competition resulted in the evolution of sperm traits that would make individual males more competitive. We ask how sperm structure and behaviour influence male reproductive success.

Human mate choice and attractiveness Using computer-manipulated images and voices, we ask how variation in signal structure influences mate preferences.

History of Science  I am  interested in the interplay between tools and ideas in the development of science, especially with respect to sperm biology and ornithology. Our book on the modern history of ornithology was published early in 2014 by Princeton Univ Press—details here.