Breeding Seasons of Waterbirds in South-western Australia — the Importance of Rainfall

Abstract

Breeding seasons are documented for forty-nine species of waterbird in south-western Australia and factors determining time of breeding are examined using data from the RAOU survey of waterbird usage of nature reserves (1981-85) and the RAOU Nest Record Scheme. Most breeding occurs in spring and regression analyses suggest that rainfall is the most important proximate cue stimulating gonadal recrudescence. Few species appear to use photoperiod and those that do nest late in the year. Although comparison of waterbird breeding seasons in various regions of Australia suggests rain-related factors are the most important proximate cues everywhere, the particular rain-related factors used may vary.