Models of sexual selection generally assume that behavioural courtship displays reflect intrinsic male qualities such as condition, and that males display with maximum intensity to attract females to mate¹. Here we use robotic females in a field experiment to demonstrate that male satin bowerbirds (Ptilonorhynchus violaceus) do not always display at maximum intensity — rather, successful males modulate their displays in response to signals from females. Our results indicate that sexual selection may favour those males that can produce intense displays but which know how to modify these according to the female response.

1. Department of Biology, University of Maryland, College Park, Maryland 20742, USA
2. Present address: Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, California 93106, USA
3. Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20742, USA

Correspondence to: Gerald Borgia¹ e-mail: Email: borgia@umail.umd.edu