Interspecific Communication and the Evolution of Alarm Calls in Birds

The remarkable similarity among species of aerial alarm calls of some European songbirds is used as a classic, textbook example of the convergent evolution of a signal design to thwart eavesdropping by hawks (Marler 1955). Despite the seminal importance of this work, no one has tested whether aerial alarm calls really are convergent, nor Marler s second functional hypothesis that convergence could be due to benefits of communication among prey species. We will record and compare calls among an Australian group of birds to test whether similarity in aerial alarm calls is due to convergence or shared ancestry. We will also carry out playback experiments to test whether call similarity facilitates communication among prey species.