Humpback whale males produce complex sounds with a hierarchical organisation of 'units' 'phrases', 'themes', and 'songs' (Payne and McVay 1971). On 9 November 2000 the vocalisations of one humpback whale were recorded at Arraial do Cabo (23° 03' S; 42° 02' W), a migratory corridor of baleen whales. The recordings were obtained using a fixed hydrophone (CN 60; 40 m deep) and a Tascam DA-60 MK 11 digital tape recorder. The recordings were analysed with Cool Edit Pro 1.2 (6,000 Hz; 32-bit; mono; 512-pt Hamming windowed time slices with 100% overlap). 19 themes were identified from a song sample of 1h 27min. The units were classified in 3 categories: harmonic, modulated amplitude and impulsive sounds (Maeda et al. 2000). For 22min 66s, there was no repetitions of themes, forming a song cycle of 12 themes. In the remainder of the song, there was a mixture of unprecedented themes with some of the 12 initial themes. The theme 7 repeated three times, theme 5 twice and themes 9, 10, and 11 once each. Theme 7 showed a variation in the repetition rate of its phrase. On the first occurrence, the phrase repeated twice. On the second time, it repeated 12 times. On the third time, it repeated 11, and in the last, 5 times. Theme 5 only had a variation between 10 and 11 repetitions. The impulsive sounds themes 10 and 11 had no phrases. Theme 9 had its phrase repeated 8 and 3 times. Themes 6, 9, 13, and 17 had 8 units; they were the most diverse themes. Razafindrakoto (2001) observed a frequency shift in humpback whale songs when peak frequency was lower than the ambient noise. The singer could shift the frequency to avoid the ambient noise (Maeda et al. 2000). We also found this frequency shift (support: CAPES, CASOP - Brazilian Navy, Redley, Cetacean Society International and Whale and Dolphin Project).
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