The male song of the Javan silvery gibbon (Hylobates moloch)

24 T. Geissmann et al. – The Male Song of the Javan Silvery GibbonAppendixConsecutive sonagrams of a complete (andrelatively short) male solo song bout of male“Paul”. This is the song bout identified as Munich1a in Table 1. The song bout has a duration ofabout 12 minutes. It begins with simple, very softsingle hoots (oo notes). Later in the song bout,starting with line 3, the oo notes are graduallyreplace by louder wa notes. By the end of part 1,wa notes are gradually combined to phrases, andother note types are added. In lines 11-14, thegibbon’s song motivation appears to declinetemporarily. After this, the male builds up hisphrases anew, starting with soft hoots again (lines15-17). This second build-up phase proceedsfaster than at the beginning of the song bout. Thesong bout ends abruptly as a great-call phrase of afemale white-cheeked crested gibbon (Nomascusleucogenys) begins in the background (this is thebegin of a duet song bout of the crested gibbons).The female phrase is blurred in the sonagrambecause of echo effects occurring in the indoorcage. (The crested gibbon pair is kept in an indoorcage adjacent to the island inhabited by the silverygibbon pair.)Whenever the intensity of the gibbon calls wasvery low, the sensitivity of the tape-recorder wasincreased during the recording. As a result, thebackground noise increases in some sections ofthe tape-recording, resulting in a grey backgroundin some of the sonagrams.kHz2101010101010101010100 2 4 6 8 10 12 14 16 sAppendix part 1kHz2101010101010101010100 2 4 6 8 10 12 14 16 sAppendix part 2