Perception of terrestrial and aerial alarm calls by honeyeaters and falcons

This study tested the responses to aerial and terrestrial alarm and distress calls in an avian predator, the brown falcon, Falco berigora, and two potential avian prey species, the New Holland honeyeater, Philidonyris novaehollandiae, and noisy miner, Manorina melanocephala. Calls were delivered from 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 easily, but they had difficulty locating the narrow-band aerial alarm calls, although they were able to detect most of these. Aerial alarm calls thus reduce risk to the caller. The performance of raptors and songbirds was similar. This result suggests that there are no reliable differences in the auditory characteristics of avian predators and prey, as have been described in species from the Northern Hemisphere.