Variation in vocalisations of the ground parrot at its northern range

Abstract

The eastern ground parrot, Pezoporus wallicus wallicus, is a vulnerable and elusive species whose ecology is little known. We recorded and analysed calls from the northern distributional range of the species. Eleven call types were identified in mainland Queensland, 10 of which were common to three study sites located within Noosa National Park. One call type was absent 50 km to the north in Cooloola National Park, where a call type not heard in Noosa was found instead. There may be less mixing of individuals between Noosa and Cooloola areas than within Noosa. Analysis of sonagrams showed that all calls are structurally simple, and generally lie within a frequency band of 2–6 kHz. There were calls with gradually ascending notes and syllables, and calls with monotone notes within syllables. The Step Ascending call is common to both Noosa and Cooloola, and modifications were detected in Yuraygir National Park and Fraser island. These call types could have derived from the same ancestral call, which may have been modified over time, with isolation maintaining the modified calls within populations. Analysis of call patterns has much potential as a conservation tool in uncommon and elusive birds, but research is required to determine the functions of various call types.