Bioacoustics of Ewartia oldfieldi

Distribution and habitat . Ewartia oldfieldi occurs coastally in the southern half of Queensland from Yeppoon south to the New South Wales border and inland to between Alpha and Tambo in central Queensland , and near Goondiwindi in southern Queensland ( Fig. 4 ). Specimens in the ANIC from Annan River, Cooktown and Cairns are, in my opinion, labelled erroneously. Adults of this species are often encountered in association with black wattles (especially Acacia leiocalyx and to some extent A. concurrens ; Mimosaceae ) and sometimes other Acacia spp. with large phyllodes that grow in sandy loam soils, often within open forest or woodland habitats. Singing males sometimes also sit on nearby vegetation, such as eucalypts ( Myrtaceae ) and Hakea spp. Adults are present from September to April, being most common from October to January. This species overlaps in geographical distribution with E. roberti n. sp. and E. lapidosa n. sp. , and sometimes occurs in sympatry with each of these taxa. Calling song . The complex calling song mode of E. oldfieldi ( Figs 1 , 5 ) contains repeated, short subphrases (0.807– 1.393 s duration; all statistics n = 28). Each subphrase is composed of a syllable sequence (0.410– 1.076 s duration) in which the gaps between syllables (initially 0.040– 0.082 s duration) sequentially reduce until the syllables (each 8–11 ms duration) coalesce into an echeme (0.114– 0.446 s duration), which is then followed by a short gap (0.063– 0.104 s duration). The subphrase then either concludes or proceeds into the accentuation, which contains either 1–2 macrosyllables (each comprising 2–4 syllables), each followed by a gap (0.063– 0.144 s ), or a short syllable sequence (2–3, or rarely 1, syllable(s), 0.117– 0.351 s duration, gaps 0.053– 0.117 s duration), which are then followed by a macrosyllable (typically 2 syllables) and another gap (0.062– 0.126 s duration). This calling song mode is typically produced at intervals throughout the day. The simple calling song mode of this species ( Fig. 6 ) contains monotonously repeated phrases (0.761– 1.014 s duration). Each phrase is composed of 1–3 macrosyllables (each comprising 4–8 syllables, 0.063– 0.108 s duration), each separated by a gap of 0.016– 0.064 s , which are then followed by an echeme (0.490– 0.822 s duration) and another gap (0.057– 0.071 s duration). This calling song mode predominates at dusk and is also occasionally produced during the day. Both song modes produce identical frequency spectra, with a highest amplitude frequency plateau typically between 9.5 and 13.5 kHz and a dominant frequency between 10.4 and 11.9 kHz (mean=11.2, n =20; e.g. Fig. 7 A). The structure of the calling song of E. oldfieldi is quite consistent across its distribution. The only remarkable potential variant is illustrated in the complex calling song structure recorded at Blackdown Tableland ( Fig. 5 F). In this recording, the syllables in the syllable sequence in each subphrase have been replaced by macrosyllables (each comprising 2–6 syllables). The recording does, however, contain only a limited sample of the complex song mode and it is possible that the unusual structure may partly be an artefact of the calling song still being in the process of transitioning from the simple mode (which predominates) into the complex mode.