Sex ratios and oral flange characteristics of selected genera of Australian honeyeaters in museum collections

Abstract

Well-developed oral flanges, typical of juvenile passerines, persist in adults of several species of Australian honeyeaters. In at least one species, changes in colour of the flange seem to be related to breeding activity. The sex ratios in collections of 19 species ranged from 0.7 to 9.9 ♂:♀. With the highest and lowest excluded to achieve homogeneity of ratios within respective genera, sex ratios of eight genera ranged from 1.3 to 2.8 ♂:♀. These are compared with ratios found by Mayr for Myzomela and with recent findings among passerines in general. It is concluded that they do not differ from other passerines because they are well within the range of ratios reported for many species from many localities, and that Mayr's data do not substantiate his claim that particularly high sex ratios are found in the meliphagid genera Myzomela and Lichmera. Sex ratios from the field, all higher than in museum collections, for Myzantha melanocephala are discussed in relation to the social organization of that species.