Hybridization of 'White-headed' and 'Orange-winged' VAried Sittellas, Daphoenositta chrysoptera leucocephala and D.c. chrysoptera (Aves: Neosittidae), in Eastern Australia

Abstract

Hybridization between the sittellas Daphoenositta chrysoptera leucocephala and D.c. chrysoptera is analysed and defined from 59 recently obtained specimens of the two forms and their hybrids in south-eastern Queensland and north-eastern New South Wales, and from older museum specimens from those areas and adjacent regions. Characteristics of age and sexual variation are identified and taken into account in the analysis. A character index for crown colour plus supplemental traits affected by hybridization shows that a true, 250-km-wide hybrid zone connects chrysoptera and leucocephala, and that there is a graded shift in the features of sittellas across the Lone. The historical factors likely to have affected the distributional history and hybridization of the two taxa are reviewed.