Perception of terrestrial and aerial alarm calls by honeyeaters and falcons

This study tested the responses to aerial and terrestrial alarm and distres s calls in an avian predator, the brown falcon, Falco berigora, and two pot ential avian prey species, the New Holland honeyeater, Philidonyris novaeho llandiae, and noisy miner, Manorina melanocephala. Calls were delivered fro m a computer system at intensities 5-20 dB above background, to birds held in large cages. All birds located the broad-band alarm and distress calls e asily, but they had difficulty locating the narrow-band aerial alarm calls, although they were able to detect most of these. Aerial alarm calls thus r educe risk to the caller. The performance of raptors and songbirds was simi lar. This result suggests that there are no reliable differences in the aud itory characteristics of avian predators and prey, as have been described i n species from the Northern Hemisphere.