Nick Davies is a zoologist, whose books with John Krebs helped to define the field of behavioural ecology. He is well known for his long-term field studies of birds. His studies of mating systems in dunnocks linked detailed observations of individual behaviour to reproductive success, using DNA profiles to assess parenthood. He showed how sexual conflict led to variable mating system outcomes, including monogamy, polygyny, polyandry and polygynandry.
He currently studies the interactions between cuckoos and their hosts, and his field experiments have revealed a continuing evolutionary ‘arms race’ of adaptation and counter-adaptation between these brood parasites and their foster parents.