Temporal Vocalization Patterns in Members of a Eucalypt Forest Bird Community: the Effects of Weather on Song Production

Abstract

A survey of diel temporal vocalisation patterns in nine members of a eucalypt forest bird community in mid-breeding season (October) showed that in five (Yellowfaced Honeyeater, Little Wattlebird, Rufous Whistler, Striated Thornbill and Superb Fairy-wren) peak singing was from about 30, to 5 minutes pre-sunrise; in one (Grey Shrikethrush) it extended from about 25 minutes pre- to 25 minutes post-sunrise; and in three (Spotted Pardalote, Common Bronzewing and Magpie Lark) it began only about sunrise. In all species there was an initial 20-40 minute period of peak singing followed by a sharp curtailment. The timing and patterns differed between species. Only three species sang regularly through the middle of the day and these vocalisation rates were only about 1/10 to 1/100 of the early morning maximum. The broad similarity of the species' patterns provided no support for the Cody & Brown (1969) suggestion that species vocalisation times have evolved to minimise interspecific acoustical interference. An independent analysis of the effects of weather on temporal vocalisation patterns showed that rain delayed morning song and depressed vocal activity in all species except the Kookaburra, fog had no effect and that dull weather depressed it in only one species, the Rufous Whistler.