The Annual Cycle of the Avadavat Amandava amandava in Fiji

Abstract

The annual cycle of the Avadavat Amandava amandava, an introduced estrildine in the Fiji islands (18°07′5, 178°27′E), is described. The main moult begins in September and ends in February. Except for loss of male nuptial plumage, little moult occurs between March and August. Gonadal development indicates that breeding occurs from March to June when there is no moult of remiges or rectrices. The diet consists almost entirely of grass seeds, Echinochloa spp. Diurnal crop content and lipid weights increase as birds prepare to roost overnight. Highest crop content weights occur in October and November. Dry weight is greatest from November to January in males, and in January and March for females. Lipid content is greatest in December and January for both sexes. Flight muscles contain about 6% of total body lipid and form about 20% of lean dry weight. Lean dry weight of the body is highest in February for males and in March for females. Lean dry weight of flight muscles is greatest in February for males and in January for females. The lean dry weight of juveniles is less than adults in May. The possible influence of changes in daylength initiating an annual moult cycle and the level of protein reserve as a proximate factor initiating breeding in tropical species is discussed.